The Popular Science Monthly Volume LXXXVI July to September, 1915 The Scientific Monthly Volume I October to December, 1915Part 3 out of 8
BY W. A. HAMOR MELLON INSTITUTE OF INDUSTRIAL RESEARCH, UNIVERSITY OF PITTSBURGH THE aim of all industrial operations is toward perfection, both in process and mechanical equipment, and every development in manufacturing creates new problems. It is only to be expected, therefore, that the industrial researcher is becoming less and less regarded as a burden unwarranted by returns. Industrialists have, in fact, learned to recognize chemistry as the intelligence department of industry, and manufacturing is accordingly becoming more and more a system of scientific processes. The accruement of technical improvements in particularly the great chemical industry is primarily dependent upon systematic industrial research, and this is being increasingly fostered by American manufacturers. Ten thousand American chemists are at present engaged in pursuits which affect over 1,000,000 wage-earners and produce over $5,000,000,000 worth of manufactured products each year. These trained men have actively and effectively collaborated in bringing about stupendous results in American industry. There are, in fact, at least nineteen American industries in which the chemist has been of great assistance, either in founding the industry, in developing it, or in refining the methods of control or of manufacture, thus ensuring profits, lower costs and uniform outputs. At the recent symposium on the contributions of the chemist to American industries, at the fiftieth meeting of the American Chemical Society in New Orleans, the industrial achievements of that scientific scout, the chemist, were brought out clearly.[1] [1] In this connection, see Hesse, J. Ind. Eng. Chem., 7 (1915), 293. The chemist has made the wine industry reasonably independent of climatic conditions; he has enabled it to produce substantially the same wine, year in and year out, no matter what the weather; he has reduced the spoilage from 25 per cent. to 0.46 per cent. of the total; he has increased the shipping radius of the goods and has made preservatives unnecessary. In the copper industry he has learned and has taught how to make operations so constant and so continuous that in the manufacture of blister copper valuations are less than $1.00 apart on every $10,000 worth of product and in refined copper the valuations of the product do not differ by more than $1.00 in every $50,000 worth of product. The quality of output is maintained constant within microscopic differences. Without the chemist the corn-products industry would never have arisen and in 1914 this industry consumed as much corn as was grown in that year by the nine states of Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, New York, New Jersey and Delaware combined; this amount is equal to the entire production of the state of North Carolina and about 80 per cent. of the production of each of the states of Georgia, Michigan and Wisconsin; the chemist has produced over 100 useful commercial products from corn, which, without him, would never have been produced. In the asphalt industry the chemist has taught how to lay a road surface that will always be good, and he has learned and taught how to construct a suitable road surface for different conditions of service. In the cottonseed oil industry, the chemist standardized methods of production, reduced losses, increased yields, made new use of wastes and by-products, and has added somewhere between $10 and $12 to the value of each bale of cotton grown. In the cement industry, the chemist has ascertained new ingredients, has utilized theretofore waste products for this purpose, has reduced the waste heaps of many industries and made them his starting material; he has standardized methods of manufacture, introduced methods of chemical control and has insured constancy and permanency of quality and quantity of output. In the sugar industry, the chemist has been active for so long a time that "the memory of man runneth not to the contrary." The sugar industry without the chemist is unthinkable. The Welsbach mantle is distinctly a chemist's invention and its successful and economical manufacture depends largely upon chemical methods. It would be difficult to give a just estimate of the economic effect of this device upon illumination, so great and valuable is it. In the textile industry, he has substituted uniform, rational, well-thought out and simple methods of treatment of all the various textile fabrics and fibers where mystery, empiricism, "rule-of-thumb" and their accompanying uncertainties reigned. In the fertilizer industry, it was the chemist who learned and who taught how to make our immense beds of phosphate rock useful and serviceable to man in the enrichment of the soil; he has taught how to make waste products of other industries useful and available for fertilization and he has shown how to make the gas works contribute to the fertility of the soil. In the soda industry, the chemist can successfully claim that he has founded it, developed it and brought it to its present state of perfection and utility, but not without the help of other technical men; the fundamental ideas were and are chemical. In the leather industry, the chemist has given us all of the modern methods of mineral tanning, and without them the modern leather industry is unthinkable. In the case of vegetable-tanned leather he has also stepped in, standardized the quality of incoming material and of outgoing product. In the flour industry the chemist has learned and taught how to select the proper grain for specific purposes, to standardize the product, and how to make flour available for certain specific culinary and food purposes. In the brewing industry, the chemist has standardized the methods of determining the quality of incoming material and of outgoing products, and has assisted in the development of a product of a quality far beyond that obtaining prior to his entry into that industry. In the preservation of foods, the chemist made the fundamental discoveries; up to twenty years ago, however, he took little or no part in the commercial operations, but now is almost indispensable to commercial success. In the water supply of cities, the chemist has put certainty in the place of uncertainty; he has learned and has shown how, by chemical methods of treatment and control, raw water of varying quality can be made to yield potable water of substantially uniform composition and quality. The celluloid industry and the nitro-cellulose industry owe their very existence and much of their development to the chemist. In the glass industry the chemist has learned and taught how to prepare glasses suitable for the widest ranges of uses and to control the quality and quantity of the output. In the pulp and paper industry, the chemist made the fundamental observations, inventions and operations and to-day he is in control of all the operations of the plant itself; to the chemist also is due the cheap production of many of the materials entering into this industry, as well as the increased and expanding market for the product itself. Sufficient has been presented to show that certain industries of the United States have been elevated by an infusion of scientific spirit through the medium of the chemist, and that manufacturing, at one time entirely a matter of empirical judgment and individual skill, is more and more becoming a system of scientific processes. The result is that American manufacturers are growing increasingly appreciative of scientific research, and are depending upon industrial researchers--"those who catalyze raw materials by brains"--as their pathfinders. It is now appropriate to consider just how industrialists are taking advantage of the universities and the products of these. THE METHODS EMPLOYED IN THE ATTACK OF INDUSTRIAL PROBLEMS[2] [2] See also Bacon, Science, N. S., 40 (1914), 871. When an industry has problems requiring solution, these problems can be attacked either inside or outside of the plant. If the policy of the industrialist is that all problems are to be investigated only within the establishment, a research laboratory must be provided for the plant or for the company. At present, in the United States, probably not more than one hundred chemical manufacturing establishments have research laboratories or employ research chemists, although at least five companies are spending over $100,000 per year in research. In Germany, and perhaps also in England, such research laboratories in connection with chemical industries have been much more common. The great laboratories of the Badische Anilin und Soda Fabrik and of the Elberfeld Company are striking examples of the importance attached to such research work in Germany, and it would be difficult to adduce any stronger argument in support of its value than the marvelous achievements of these great firms. A frequent difficulty encountered in the employment of researchers or in the establishment of a research laboratory, is that many manufacturers have been unable to grasp the importance of such work, or know how to treat the men in charge so as to secure the best results. The industrialist may not even fully understand just what is the cause of his manufacturing losses or to whom to turn for aid. If he eventually engages a researcher, he is sometimes likely to regard him as a sort of master of mysteries who should be able to accomplish wonders, and, if he can not see definite results in the course of a few months, is occasionally apt to consider the investment a bad one and to regard researchers, as a class, as a useless lot. It has not been unusual for the chemist to be told to remain in his laboratory, and not to go in or about the works, and he must also face the natural opposition of workmen to any innovations, and reckon with the jealousies of foremen and of various officials. From the standpoint of the manufacturer, one decided advantage of the policy of having all problems worked out within the plant is that the results secured are not divulged, but are stored away in the laboratory archives and become part of the assets and working capital of the corporation which has paid for them; and it is usually not until patent applications are filed that this knowledge, generally only partially and imperfectly, becomes publicly known. When it is not deemed necessary to take out patents, such knowledge is often permanently buried. In this matter of the dissemination of knowledge concerning industrial practice, it must be evident to all that there is but little cooperation between manufacturers and the universities. Manufacturers, and especially chemical manufacturers, have been quite naturally opposed to publishing any discoveries made in their plants, since "knowledge is power" in manufacturing as elsewhere, and new knowledge gained in the laboratories of a company may often very properly be regarded as among the most valuable assets of the concern. The universities and the scientific societies, on the other hand, exist for the diffusion of knowledge, and from their standpoint the great disadvantage of the above policy is this concealment of knowledge, for it results in a serious retardation of the general growth and development of science in its broader aspects, and renders it much more difficult for the universities to train men properly for such industries, since all the text-books and general knowledge available would in all probability be far behind the actual manufacturing practice. Fortunately, the policy of industrial secrecy is becoming more generally regarded in the light of reason, and there is a growing inclination among manufacturers to disclose the details of investigations, which, according to tradition, would be carefully guarded. These manufacturers appreciate the facts that public interest in chemical achievements is stimulating to further fruitful research, that helpful suggestions and information may come from other investigators upon the publication of any results, and that the exchange of knowledge prevents many costly repetitions. INDUSTRIAL FELLOWSHIPS If the manufacturer elects to refer his problem to the university or technical school--and because of the facilities for research to be had in certain institutions, industrialists are following this plan in constantly increasing numbers--such reference may take the form of an industrial fellowship and much has been said and may be said in favor of these fellowships. They allow the donor to keep secret for three years the results secured, after which they may be published with the donor's permission. They also secure to him patent rights. They give highly specialized training to properly qualified men, and often secure for them permanent positions and shares in the profits of their discoveries. It should be obvious at the outset that a fellowship of this character can be successful only when there are close confidential relations obtaining between the manufacturer and the officer in charge of the research; for no such cooperation can be really effective unless based upon a thorough mutual familiarity with the conditions and an abiding faith in the integrity and sincerity of purpose of each other. It is likely to prove a poor investment for a manufacturer to seek the aid of an investigator if he is unwilling to take such expert into his confidence and to familiarize him with all the local and other factors which enter into the problem from a manufacturing standpoint. THE MELLON INSTITUTE OF INDUSTRIAL RESEARCH[3] [3] For a detailed description of the Mellon Institute and its work, see Bacon and Hamor, J. Ind. Eng. Chem., 7 (1915), 326-48. According to the system of industrial research in operation at the Mellon Institute of Industrial Research of the University of Pittsburgh, which is not, in any sense of the word, a commercial institution, a manufacturer having a problem requiring solution may become the donor of a fellowship; the said manufacturer provides the salary of the researcher selected to conduct the investigation desired, the institute furnishing such facilities as are necessary for the conduct of the work. The money paid in to found a fellowship is paid over by the institute in salary to the investigator doing the work. In every case, this researcher is most carefully selected for the problem in hand. The institute supplies free laboratory space and the use of all ordinary chemicals and equipment. The chemist or engineer who is studying the problem works under the immediate supervision of men who are thoroughly trained and experienced in conducting industrial research. At the present time, the Mellon Institute, which, while an integral part of the University of Pittsburgh, has its own endowment, is expending over $150,000 annually for salaries and maintenance. A manufacturer secures for a small expenditure--just sufficient to pay the salary of the fellow, as the man engaged on the investigation is called--all the benefits of an organization of this size, and many have availed themselves of the advantages, twenty-eight companies maintaining fellowships at the present time. Each fellow has the benefit of the institute's very excellent apparatus, chemical and library equipment--facilities which are so essential in modern research; and because of these opportunities and that of being able to pursue post-graduate work for higher degrees, it has been demonstrated that a higher type of researcher can be obtained by the institute for a certain remuneration than can be generally secured by manufacturers themselves. There is a scarcity of men gifted with the genius for research, and it requires much experience in selecting suitable men and in training them to the desirable degree of efficiency, after having determined the special qualities required. Important qualifications in industrial researchers are keenness, inspiration and confidence; these are often unconsidered by manufacturers, who in endeavoring to select, say, a research chemist, are likely to regard every chemist as a qualified scientific scout. All researches conducted at the Mellon Institute are surrounded with the necessary secrecy, and any and all discoveries made by the fellow during the term of his fellowship become the property of the donor. When the Mellon Institute moved into its $350,000 home in February, 1915, the industrial fellowship system in operation therein passed out of its experimental stage. During the years of its development no inherent sign of weakness on the part of any one of its constituent factors appeared; in fact, the results of the fellowships have been uniformly successful. While problems have been presented by companies which, upon preliminary investigation, have proved to be so difficult as to be practically impossible of solution, there have been so many other problems confronting these companies that important ones were found which lent themselves to solution; and often the companies did not realize, until after investigations were started, just what the exact nature of their problems was and just what improvements and savings could be made in their manufacturing processes. Fellowships at the Mellon Institute are constantly increasing in the amounts subscribed by industrialists for their maintenance and, as well, in their importance. The renewal, year after year, of such fellowships, as those on baking, petroleum and ores, goes to show the confidence which industrialists have in the Mellon Institute. Again, the large sums of money which are being spent by companies in bringing small unit plants to develop the processes which have been worked out in the laboratory, demonstrate that practical results are being secured. Where there have been sympathy and hearty cooperation between the Mellon Institute and the company concerned, the institute has been able to push through to a successful conclusion large scale experiments in the factory of the company, which in the beginning of the fellowship seemed almost impossible: it may be said that the results of the fellowships at the Mellon Institute indicate that a form of service to industry has been established, the possibilities of which no man can say. A FEW CLASSIC UNKNOWNS IN MATHEMATICS BY PROFESSOR G. A. MILLER UNIVERSITY OF ILLINOIS KING HIERO is said to have remarked, in view of the marvelous mechanical devices of Archimedes, that he would henceforth doubt nothing that had been asserted by Archimedes. This spirit of unbounded confidence in those who have exhibited unusual mathematical ability is still extant. Even our large city papers sometimes speak of a mathematical genius who could solve every mathematical problem that was proposed to him. The numerous unexpected and far-reaching results contained in the elementary mathematical text-books, and the ease with which the skilful mathematics teachers often cleared away what appeared to be great difficulties to the students have filled many with a kind of awe for unusual mathematical ability. In recent years the unbounded confidence in mathematical results has been somewhat shaken by a wave of mathematical skepticism which gained momentum through some of the popular writings of H. Poincare and Bertrand Russell. As instances of expressions which might at first tend to diminish such confidence we may refer to Poincare's contention that geometrical axioms are conventions guided by experimental facts and limited by the necessity to avoid all contradictions, and to Russell's statement that "mathematics may be defined as the subject in which we never know what we are talking about nor whether what we are saying is true." The mathematical skepticism which such statements may awaken is usually mitigated by reflection, since it soon appears that philosophical difficulties abound in all domains of knowledge, and that mathematical results continue to inspire relatively the highest degrees of confidence. The unknowns in mathematics to which we aim to direct attention here are not of this philosophical type but relate to questions of the most simple nature. It is perhaps unfortunate that in the teaching of elementary mathematics the unknowns receive so little attention. In fact, it seems to be customary to direct no attention whatever to the unsolved mathematical difficulties until the students begin to specialize in mathematics in the colleges or universities. One of the earliest opportunities to impress on the student the fact that mathematical knowledge is very limited in certain directions presents itself in connection with the study of prime numbers. Among the small prime numbers there appear many which differ only by 2. For instance, 3 and 5, 5 and 7, 11 and 13, 17 and 19, 29 and 31, constitute such pairs of prime numbers. The question arises whether there is a limit to such pairs of primes, or whether beyond each such pair of prime numbers there must exist another such pair. This question can be understood by all and might at first appear to be easy to answer, yet no one has succeeded up to the present time in finding which of the two possible answers is correct. It is interesting to note that in 1911 E. Poincare transmitted a note written by M. Merlin to the Paris Academy of Sciences in which a theorem was announced from which its author deduced that there actually is an infinite number of such prime number pairs, but this result has not been accepted because no definite proof of the theorem in question was produced. Another unanswered question which can be understood by all is whether every even number is the sum of two prime numbers. It is very easy to verify that each one of the small even numbers is the sum of a pair of prime numbers, if we include unity among the prime numbers; and, in 1742, C. Goldbach expressed the theorem, without proof, that every possible even number is actually the sum of at least one pair of prime numbers. Hence this theorem is known as Goldbach's theorem, but no one has as yet succeeded in either proving or disproving it. Although the proof or the disproof of such theorems may not appear to be of great consequence, yet the interdependence of mathematical theorems is most marvelous, and the mathematical investigator is attracted by such difficulties of long standing. These particular difficulties are mentioned here mainly because they seem to be among the simplest illustrations of the fact that mathematics is teeming with classic unknowns as well as with knowns. By classic unknowns we mean here those things which are not yet known to any one, but which have been objects of study on the part of mathematicians for some time. As our elementary mathematical text-books usually confine themselves to an exposition of what has been fully established, and hence is known, the average educated man is led to believe too frequently that modern mathematical investigations relate entirely to things which lie far beyond his training. It seems very unfortunate that there should be, on the part of educated people, a feeling of total isolation from the investigations in any important field of knowledge. The modern mathematical investigator seems to be in special danger of isolation, and this may be unavoidable in many cases, but it can be materially lessened by directing attention to some of the unsolved mathematical problems which can be most easily understood. Moreover, these unsolved problems should have an educational value since they serve to exhibit boundaries of modern scientific achievements, and hence they throw some light on the extent of these achievements in certain directions. Both of the given instances of unanswered classic questions relate to prime numbers. As an instance of one which does not relate to prime numbers we may refer to the question whether there exists an odd perfect number. A perfect number is a natural number which is equal to the sum of its aliquot parts. Thus 6 is perfect because it is equal to 1 + 2 + 3, and 28 is perfect because it is equal to 1 + 2 + 4 + 7 + 14. Euclid stated a formula which gives all the even perfect numbers, but no one has ever succeeded in proving either the existence or the non-existence of an odd perfect number. A considerable number of properties of odd perfect numbers are known in case such numbers exist. In fact, a very noted professor in Berlin University developed a series of properties of odd perfect numbers in his lectures on the theory of numbers, and then followed these developments with the statement that it is not known whether any such numbers exist. This raises the interesting philosophical question whether one can know things about what is not known to exist; but the main interest from our present point of view relates to the fact that the meaning of odd perfect number is so very elementary that all can easily grasp it, and yet no one has ever succeeded in proving either the existence or the non-existence of such numbers. It would not be difficult to increase greatly the number of the given illustrations of unsolved questions relating directly to the natural numbers. In fact, the well-known greater Fermat theorem is a question of this type, which does not appear more important intrinsically than many others but has received unusual attention in recent years on account of a very large prize offered for its solution. In view of the fact that those who have become interested in this theorem often experience difficulty in finding the desired information in any English publication, we proceed to give some details about this theorem and the offered prize. The following is a free translation of a part of the announcement made in regard to this prize by the Konigliche Gesellschaft der Wissenschaften, Gottingen, Germany: On the basis of the bequest left to us by the deceased Dr. Paul Wolskehl, of Darmstadt, a prize of 100,000 mk., in words, one hundred thousand marks, is hereby offered to the one who will first succeed to produce a proof of the great Fermat theorem. Dr. Wolfskehl remarks in his will that Fermat had maintained that the equation x z could not be satisfied by integers whenever prime number. This Fermat theorem is to be proved either generally in the sense of Fermat, or, in supplementing the investigations by Kummer, published in Crelle's Journal, volume 40, it is to be proved for all values of is actually true. For further literature consult Hibert's report on the theory of algebraic number realms, published in volume 4 of the Jahreshericht der Deutschen Mathernatiker-Vereinigung, and volume 1 of the Encyklopadie der mathematischen Wissenschaften. The prize is offered under the following more particular conditions. The Konigliche Gesellschaft der Wissenschaften in Gottingen decides independently on the question to whom the prize shall be awarded. Manuscripts intended to compete for the prize will not be received, but, in awarding the prize only such mathematical papers will be considered as have appeared either in the regular periodicals or have been published in the form of monographs or books which were for sale in the book-stores. The Gesellschaft leaves it to the option of the author of such a paper to send to it about five printed copies. Among the additional stipulations it may be of interest to note that the prize will not be awarded before at least two years have elapsed since the first publication of the paper which is adjudged as worthy of the prize. In the meantime the mathematicians of various countries are invited to express their opinion as regards the correctness of this paper. The secretary of the Gesellschaft will write to the person to whom the prize is awarded and will also publish in various places the fact that the award has been made. If the prize has not been awarded before September 13, 2007, no further applications will be considered. While this prize is open to the people of all countries it has become especially well known in Germany, and hundreds of Germans from a very noted university professor of mathematics to engineers, pastors, teachers, students, bankers, officers, etc., have published supposed proofs. These publications are frequently very brief, covering only a few pages, and usually they disclose the fact that the author had no idea in regard to the real nature of the problem or the meaning of a mathematical proof. In a few cases the authors were fully aware of the requirements but were misled by errors in their work. Although the prize was formally announced more than seven years ago no paper has as yet been adjudged as fulfilling the conditions. It may be of interest to note in this connection that a mathematical proof implies a marshalling of mathematical results, or accepted assumptions, in such a manner that the thing to be proved is a NECESSARY consequence. The non-mathematician is often inclined to think that if he makes statements which can not be successfully refuted he has carried his point. In mathematics such statements have no real significance in an attempted proof. Unknowns must be labeled as such and must retain these labels until they become knowns in view of the conditions which they can be proved to satisfy. The pure mathematician accepts only necessary conclusions with the exception that basal postulates have to be assumed by common agreement. The mathematical subject in which the student usually has to contend most frequently with unknowns at the beginning of his studies is the history of mathematics. The ancient Greeks had already attempted to trace the development of every known concept, but the work along this line appears still in its infancy. Even the development of our common numerals is surrounded with many perplexing questions, as may be seen by consulting the little volume entitled "The Hindu-Arabic Numerals," by D. E. Smith and L. C. Karpinski. The few mathematical unknowns explicitly noted above may suffice to illustrate the fact that the path of the mathematical student often leads around difficulties which are left behind. Sometimes the later developments have enabled the mathematicians to overcome some of these difficulties which had stood in the way for more than a thousand years. This was done, for instance, by Gauss when he found a necessary and sufficient condition that a regular polygon of a prime number of sides can be constructed by elementary methods. It was also done by Hermite, Lindemann and others by proving that epsilon and rho are transcendental numbers. While such obstructions are thus being gradually removed some of the most ancient ones still remain, and new ones are rising rapidly in view of modern developments along the lines of least resistance. These obstructions have different effects on different people. Some fix their attention almost wholly on them and are thus impressed by the lack of progress in mathematics, while others overlook them almost entirely and fix their attention on the routes into new fields which avoid these difficulties. A correct view of mathematics seems to be the one which looks at both, receiving inspiration from the real advances but not forgetting the desirability of making the developments as continuous as possible. At any rate the average educated man ought to know that there is no mathematician who is able to solve all the mathematical questions which could be proposed even by those having only slight attainments along this line. THE ABORIGINAL ROCK-STENCILLINGS OF NEW SOUTH WALES BY DR. CHAS. B. DAVENPORT COLD SPRING HARBOR, N. Y. IN a number of places in eastern Australia curious aboriginal markings are found on the faces of the sandstone cliffs. A good idea of them is given by the photographs. These came from Wolgan Gap near Wallerang in the Blue Mountain region of New South Wales. They are found on overhanging rocks that have served as shelters or camping places for the aborigines and which doubtless have protected their works of art. These stencillings are made by a sort of spatter work, something like that in vogue a generation ago in this country, using leaves, etc., as forms. The rocks at Wolgan Gap are a coarse sandstone stained almost black by an iron oxide derived from included bands of ironstone. These black surfaces were selected by the artists. Nearby in the rock is a band of shale which had disintegrated at its exposed edge to a white powder. The native artist put some of this white powder in his mouth, placed his hand or foot upon the rock, and blew the moistened powder upon and around his outstretched fingers or toes. When he removed them they were outlined on the rock. Since the sandstone is coarse and deeply pitted, the moist powder was blown into minute cavities where it has remained despite the erosive activities of some generations. The presence of the powder is shown on the photographs as a sort of halo around the object. The hands are either right or left, and, in some cases, both hands seem to have been stencilled at once. Sometimes the whole arm and hand are stencilled together, and in one of the photographs a boomerang is shown. The age of these stencils is not known. They were first discovered at Wolgan Gap about sixty years ago, but others have been known for a longer time, for instance, those at Greenwich, Parametta River, near Sydney. The significance of these stencillings has been the subject of some controversy. The natives may have been induced to make them as boys carve their names on benches or even rocks. The materials for making the stencillings were present and, the example once having been set, others would emulate it. It is interesting that similar stencillings of the hands were made by cave men on the walls of some of the European caves, as, for instance, those of Aurignac in southern France. Evidently spatter work is no modern pastime. THE PROGRESS OF SCIENCE SUBSTITUTES FOR WAR THIS war, beyond measure disastrous to civilization, is a trial also of our democracy. We may hope that it is an old-world war and an old-men's war, repugnant to the genius of our newer life. The statements of some of our public men and the contents of some of our newspapers can not be read without discouragement. But it is also true that there has perhaps not appeared a cartoon in any American newspaper tending to glorify war, and no legislation has so far been enacted in preparation for war. There is good reason to believe that the people have not been infected by the contagion of blood. As Professor Patrick argued in a recent issue of the Monthly, man is by genetic inheritance a fighting and a playing animal, not an animal delighting in steady work. The ape and the tiger will be exterminated elsewhere in nature before they will be suppressed in man. It is a slow process, but surely proceeding. The writer of this note has determined the proportion of each century in which the leading nations have been engaged in war. The curve thus found has no great reliability; for it does not take into account the percentages of the peoples concerned, but its course clearly indicates that even under circumstances as they have been, wars will come to an end. And there is good reason to believe that the newer condition--universal education and universal suffrage, democratic control, improved economic conditions of living for the people, the scientific attitude--will tend to bend the curve more rapidly toward the base line of permanent "peace on earth and good will to men." While man has inherited instincts which exhibit themselves in playing and fighting, the same instincts may by social control be diverted to playing the games of art or science, to fighting disease and vice. It is rarely wise or feasible to attempt to suppress instincts; they should be directed so as to provide desirable conduct. Loyalty to family, to group, to neighborhood and to nation can not be lightly cast away for an abstract cosmopolitanism. But it can be expressed otherwise than by seizing everything in sight by cunning or by violence. William James, the great psychologist, in one of his brilliant essays published in The Popular Science Monthly for October, 1910, tells us that history is a bath of blood; we inherit the war-like type; our ancestors have bred pugnacity into our bone and marrow; showing the irrationality and horror of war does not prevent it; but a moral equivalent can be found by enlisting an army to toil and suffer pain in doing the hard and routine work of the world. It is doubtful, however, if the "gilded youths" to whom James refers would accept "dish-washing, clothes-washing and window-washing, road-building and tunnel-making, foundries and stoke-holes," as a substitute for war, and for the great mass of the people there is more than enough of these things. It is to escape from them that we seek excitement and adventure, intoxication by drugs and war. Professor Cannon, of Harvard University, proposes international football and other athletic contests as substitutes for war. The adrenal glands, whose secretions excite the combative and martial emotions, must function, and their activity, he argues, can be directed in this way. Mr. Bryan has just now made the proposal that we build six great national roads by which armies might be collected for defence; the secretary of the navy has founded a Naval Inventions Board; the postmaster general has suggested that aeroplanes be used to deliver mail in order that we may have an aerial corps ready for service. There may be an element of the absurd in some of these proposals, as there would be in using submarines to catch cod fish, so that there might be practise in building and managing such crafts for peaceful pursuits. There is, however, psychological justification for aiming to direct the emotions so that their discharge is not destructive, but of benefit to the nation and to the world. Such would be the development of our national resources, the construction of railways, roads, waterworks and the like; social and political reforms; progress in the care of public health, in education and in scientific research. It is proposed that the next congress should spend half a billion dollars on the army and navy. It is possible that on a plebiscite vote, exactly under existing conditions, a majority would vote to make the department of war a department of public works, military defence being only one of its functions, and to spend the sum proposed on public works useful in case of war, but not an incitement to war. NATIONAL WEALTH AND PUBLIC INDEBTEDNESS WHILE the lives and the wealth of the European nations are being sacrificed on a scale hitherto unparalleled, it is well in the interests of those nations, as well as of our own, that we conserve the lives and wealth of our own people. The greatest wealth of a nation is its children, its productive workers, its scientific men and other leaders, its accumulated knowledge and social traditions. These are immeasurable, but the Bureau of the Census has recently prepared a report on the material wealth and indebtedness, according to which it is estimated that the total value of all classes of property in the United States, exclusive of Alaska and the insular possessions, in 1912, was $187,739,000,000, or $1,965 per capita. This estimate is presented merely as the best approximation which can be made from the data available and as being fairly comparable with that published eight years ago. The increase between 1904 and 1912 was 75 per cent., for the total amount and 49 per cent. for the per capita. Real estate and improvements, including public property, alone constituted $110,677,000,000, or 59 per cent. of the total, in 1912. The next greatest item, $16,149,000,000, was contributed by the railroads; and the third, $14,694,000,000, represented the value of manufactured products, other than clothing and personal adornments, furniture, vehicles and kindred property. The net public-indebtedness in 1913 amounted to $4,850,461,000. This amount was made up as follows: National debt, $1,028,564,000, or $10.59 per capita; state debt, $345,942,000, or $3.57 per capita; county debt, $371,528,000, or $4.33 per capita; and municipal debt, $2,884,883,000, or $54.27 per capita. Thus the average urban citizen's share of the net federal, state, county and municipal debt combined was $72.76; and the average rural citizen's share of the net federal, state and county debt combined was $18.49. The total federal debt in 1910 was $2,916,205,000, of which amount $967,366,000 was represented by bonds, $375,682,000 by non-interest-bearing debt (principally United States notes or "greenbacks"), and $1,573,157,000 by certificates and notes issued on deposits of coin and bullion. Against this indebtedness there was in the treasury $1,887,641,000 in cash available for payment of debt, leaving the net national indebtedness at $1,028,564,000, or $10.59 per capita. The increase in the net indebtedness between 1902 and 1913 amounted to 6 per cent., but for the per capita figure there was a decrease of 13 per cent. The burden due to the national debt is thus very light in comparison with that imposed by the indebtedness of other great nations. The state debt, however, rests still more easily on the shoulders of the average citizen, being only one third as great as that of the nation. The total state indebtedness in 1913 was $422,797,000, and the net debt--that is, the total debt less sinking-fund assets--was $345,942,000, or $3.57 per capita. The net debt increased by 44.5 per cent. between 1902 and 1913, and the per capita net debt by 18 per cent. The total county debt in 1913 amounted to $393,207,000, of which amount $371,528,000, or $4.33 per capita, was net debt. The net indebtedness increased by 89 per cent. between 1902 and 1913, and the per capita net indebtedness by 55 per cent. By far the greatest item of indebtedness in this country is that of municipalities. This amounted in 1913 to an aggregate of $3,460,000,000, of which $2,884,883,000, or $54.27 per capita, represented net indebtedness. The rate of increase in net indebtedness between 1902 and 1913 was 114 per cent. While the nations of Europe are involving themselves in the toils of debts, we should use our vast surplus wealth to pay the national, state and municipal debts, even those contracted for public improvements. We save every year about $100 for each adult and child of the country and waste about an equal sum. It would be well if this wealth could be invested for the benefit of each, and education and scientific research are the most productive of all investments. SCIENTIFIC ITEMS WE record with regret the death of Karl Eugen Guthe, professor of physics in the University of Michigan and dean of the Graduate School, in Hanover, Germany; of John Howard Van Amringe, long dean of Columbia College and professor of mathematics; of Carlos J. Finlay, known for his advocacy of the theory that yellow fever is transmitted by mosquitoes; of A. J. Herbertson, of Wadham College, Oxford, professor of geography in the university; of Julius von Payer, the distinguished polar explorer and artist, of Vienna, and of Guido Goldsehmiedt, professor of chemistry in the University of Vienna. DR. JACQUES LORE, of the Rockefeller Institute for Medical Research, has been elected a foreign fellow of the Linnean Society, London.--Dr. David Bancroft Johnson, president of Winthrop Normal and Industrial College, of Rockhill, S. C., has been elected president of the National Education Association, in succession to Dr. David Starr Jordan, chancellor of Stanford University. A MEMORIAL to Johann C. Reil, the anatomist, has been erected in Halle. It stands in front of the university clinic, the seat of his labors until called to Berlin in 1810. He died in 1813, aged fifty-five years.--A bronze bas-relief--the work of Mr. S. N. Babb--is about to be erected in St. Paul's Cathedral in memory of Captain Scott and his companions who perished in the Antarctic. At the request of the committee responsible for the memorial an inscription has been written by Lord Curzon, which reads as follows: "In memory of Captain Robert Falcon Scott, C.V.O., R.N., Dr. Edward Adrian Wilson, Captain Lawrence E. G. Oates, Lieut. Henry R. Bowers and Petty Officer Edgar Evans, who died on their return journey from the South Pole in February and March, 1912. Inflexible of purpose, steadfast in courage, resolute in endurance in the face of unparalleled misfortune. Their bodies are lost in the Antarctic ice. But the memory of their deeds is an everlasting monument." THE SCIENTIFIC MONTHLY NOVEMBER, 1915 PAPUA, WHERE THE STONE-AGE LINGERS BY DR. ALFRED GOLDSBOROUGH MAYER WITH their undaunted spirit for braving the wilds, the English entered New Guinea in 1885. For centuries the great island had remained a mere outline upon the map the fever-haunted glades of its vast swamps and the broken precipices of its mountain ranges having defied exploration, more than the morose and savage character of its inhabitants. Even in the summer of 1913, Massy Baker the explorer, discovered a lake probably 100 miles or more in shore-line, which had remained hidden in the midst of the dark forests of the Fly and Strickland River regions, and here savages still in the stone age, who had never seen a white man, measured the potency of their weapons against the modern rifle. To-day there are vast areas upon which the foot of the white man has not yet trodden, and of all the regions in the tropical world New Guinea beckons with most alluring fascination to him to whom adventure is dearer than life. Far back in the dawn of European exploration, the Portuguese voyager Antonio de Abreu, may have seen the low shores of western New Guinea, but it is quite certain that sixteen years later, in 1527, Don Jorge de Meneses cruised along the coast and observed the wooly-headed natives whom he called "Papuas." The name "New Guinea" was bestowed upon the island by the Spanish captain, Ynigo Ortz de Retes, in 1515, when he saw the negroid natives of its northern shores. Then there came and passed some of the world's greatest navigators. Torres wandering from far Peru, to unknowingly discover the strait which bears his name; Dampier, the buccancer-adventurer, and, in 1768, the cultured, esthetic Bougainville, who was enraptured by the beauty of the deep forest-fringed fjords of the northeastern coast. Cook, greatest of all geographers, mapped the principal islands and shoals of the intricate Torres Strait in 1770; and a few years later came Captain Bligh, the resourceful leader of his faithful few, crouching in their frail sail boat that had survived many a tempest; since the mutineers of the Bounty had cast them adrift in the mid-Pacific. In the early years of the nineteenth century the scientifically directed Astrolabe arrived, under the command of Dumont D'Urville, and, later, Captain Owen Stanley in the Rattlesnake, with Huxley as his zoologist, Then, in 1858, came Alfred Russel Wallace, the codiscoverer of Darwinism, who, by the way, is said to have been the first Englishman who ever actually resided in New Guinea. The daring explorers and painstaking surveyors came and went, but the great island remained a land of dread and mystery, guarded by the jagged reefs of its eastern shores, and the shallow mud flats, stretching far to sea-ward beyond the mouths of the great rivers of its southern coast. So inaccessible was Papua that even the excellent harbor of Port Moresby, the site: of the present capital, was not discovered until 1873. One has but to stifle for a while in the heavy air that flows lifeless and fetid over the lowlands as if from a steaming furnace, or to scent the rank odors of the dark swamps, where for centuries malaria must linger, to appreciate the reason for the long-delayed European settlement of the country. But those who blaze the path of colonial progress are not to be deterred by temperatures or smells; let us remember that Batavia, "the white man's graveyard," is now one of the world's great commercial centers; and Jamaica, the old fever camp of the British army, is now a health resort for tourists. Papua, the land of the tired eyes and the earnest face, of the willing spirit and the weary body, waning as strength fails year by year in malaria and heat, the land wherein the heart aches for the severed ties of wife and home; its history has hardly yet begun, but the reward of generations of heroism will be the conquest of another empire where England's high standards of freedom are to he raised anew. A victory of peace it is to be, as noble as any yet achieved in war; and great through its death roll, and forgotten though the workers be, the fruits of their labors will bless that better world Great Britain is preparing for those of ages yet to come. There are great resources in Papua with its area of 90,500 square miles. Untrodden forests where the dark soil moulders beneath the everlasting shade; swamps bearing a harvest of thousands of sago and nipa palms, and mountains in a riot of contorted peaks rising to a height of 13,200 feet in the Owen Stanley range. It is still a country of surprises, as when petroleum fields, probably 1,000 square miles in area, were discovered only about four years ago along the Vailala River, the natives having concealed their knowledge of the bubbling gas springs through fear of offending the evil spirits of the place. It is evident that although the country has been merely glanced over, there are both agricultural and mineral resources of a promising nature in Papua. It remains but for modern medicine to over-come the infections of the tropics for the region to rise into prominence as one of the self-supporting colonies of the British empire. The early history of British occupation centers around the striking personality of James Chalmers, the great-hearted, broad-minded, missionary, one of the most courageous who ever devoted his life to extending the brotherhood of the white man's ideals. Chafing, as a young man, under the petty limitations of his mission in the Cook Islands, he sought New Guinea, as being the wildest and most dangerous field in the tropical Pacific. Here, for twenty-five years, he devoted his mighty soul to the work of introducing the rudiments of civilization and Christianity to the most sullen and dangerous savages upon earth. Scores of times his life hung in the balance of native caprice; wives and friends died by his side, victims to the malignant climate and to native spears, while he seemed to possess a charmed life; until, true to his prediction, he was murdered by the cannibals of Dopina at the mouth of the Fly River in 1901. Hundreds of scattered tribes had learned to revere their great leader "Tamate," as they called him, who brought peace and prosperity to his followers. Yet a danger to Papua that he himself foresaw and did all in his power to avert came as a result of the introduction of the very civilization of which he was the champion, for with peace came new wants that the most unscrupulous of traders at once sought to supply at prices ruinous to the social and moral welfare of the natives. Also, the proximity of Queensland threatened to become a menace; for Chalmers himself was well aware of the dark history of the "blackbird trade" wherein practical slavery was forced upon the indentured laborers, lured from their island homes to toil as hopeless debtors upon the Australian plantations. A government of the natives for the native interests he desired; not one administered from the Australian mainland in the interest of alien whites. The hopes of Chalmers were only partially realized, for Papua is still only a territory of Australia. In most respects this condition appears to be unfortunate. The crying needs of a new country are usually peculiarly local and not likely to be appreciated by a distant ruling power. Moreover, Australia is itself an undeveloped land and requires too large a proportion of its own capital for expansion at home to be a competent protector of a colony across the sea. One feels that Papuan development might have proceeded with greater smoothness had the colony been more directly under the British empire, rather shall an Australian dependency. The strategic necessity that Australia should command both the northern and the southern shores of Torres Straits might still have been secured without the sacrifice of any important initiative in matters of government upon the part of Papua. The cardinal evil that Chalmers feared has, however, been averted. The natives still own 97 1/2 per cent. of the entire land area, and wise laws guard them in this precious possession, and aim to protect them from all manner of unjust exploitation. It is much to the credit of the government that the cleanest native villages and the most healthy, ambitious and industrious tribes, are those nearest the white settlements. Contact between the races has resulted in the betterment, not in the degradation, of the Papuan natives. The touch of a master hand is apparent in a multitude of details in managing the natives of Papua; and it is of interest to see that in broad essentials the plan of government is adapted from that which the English have put to the test of practice in Fiji; the modifications being of a character designed to meet the conditions peculiar to Melanesia, wherein the chiefs are relatively unimportant in comparison with their role in the social systems of the Polynesians and Fijians. Foremost in the shaping of the destiny of Papua stands the commanding figure of Sir William Macgregor, administrator and lieutenant governor from 1888 to 1898. As a young man Macgregor was government physician in Fiji, where he became prominent not only as a competent guardian of the health of the natives, but as a leader in the suppression of the last stronghold of cannibalism along the Singatoka River. In Papua his tireless spirit found a wide field for high endeavor, and upon every department of the government one finds to-day the stamp of his powerful personality. Nor did he remain closeted in Port Moresby, a stranger to the races of his vast domains, for over the highest mountains and through the densest swamps his expeditions forced their way; the Great Governor always in the van. It was thus that he conquered the fierce Tugeri of the Dutch border, who for generations had been the terror of the coasts; and wherever his expeditions passed, peace followed, and the law of the British magistrate supplanted the caprice of the sorcerer. But his hardest fight was not with the mountain wilds or the malarious morasses. It was to secure from the powerful ones of his own race the privileges of freemen for the natives of Papua. In his youth he had seen the blessings that came with the advent of British rule in Fiji; and here, in broad New Guinea, upon a vaster scale, he strove to make fair play the dominant note in the white man's treatment of a savage race. Arrayed against Chalmers and Macgregor were conservatism and suspicion founded in ancient precedent, and a commercial avarice that saw in native exploitation the readiest means to convert New Guinea into a "white man's country." Aversion there was also in high places to embarking upon a possibly fruitless experiment, involving generations of labor and expense for a remote and uncertain harvest. Chalmers and Macgregor, however, through the force of their high convictions and the wisdom of their wide experience, won the great fight for fairness; for civilization's cardinal victories are those, not of the soldier, but of the civil servant who dares risk his reputation and his all for those things he deems just and generous; and when Papua comes to erect statues to her great leaders, those of these two patriots must surely occupy the highest places, as champions of the liberties of the weak. The noble policy of Macgregor is still, and let us hope it long may be, the keynote of the administration in Papua, which to-day is being ably carried forward under the great governor's disciple, the Honorable John H. P. Murray. The proclamation given by Captain Erskine in 1884 declared that a British Protectorate had become essential for the safeguarding of the lives and property of the natives of New Guinea and for the purpose of preventing the occupation of the country by persons whose proceedings might lead to injustice, strife and bloodshed, or whose illegitimate trade might endanger the liberties and alienate the lands of the natives. It is, however, one thing for a government to declare its altruistic intentions, but often quite another to carry them into effect. In Papua, every effort has been made to prevent robbery of the natives by unscrupulous whites. The natives are firmly secured in the possession of their lands, which they can neither sell, lease nor dispose of, except to the government itself. Thus the natives and the government are the only two landlords in the country. To acquire land in Papua, the European settler must rent it from the government, for he is not permitted to acquire fee simple rights. The whites are thus tenants of the government, and are subject to such rules and regulations as their landlord may decree. The tenant is, however, recognized as the creator and owner of any improvements he may erect upon the land, and, at the expiration of his lease, the government undertakes to pay him a fair compensation for such improvements, provided he has lived up to the letter of regulations respecting his tenure. For agricultural land a merely nominal rental is demanded, ranging from nothing for the first ten years to a final maximum of six pence per acre; yet this system has had the effect of retarding European settlement, for, although its area is twice that of Cuba, Papua had but 1,064 whites in 1912, and only one one hundred and seventy-fourth of the territory is held under lease. Men of the type who can conquer the primeval forests and create industries prefer to own their land outright, and are apt to resent the restrictions of complex government regulations, however wisely administered. Socialism, while it may in some measure be desirable in old and settled communities, serves but to dull that sense of personal freedom which above all spurs the pioneer onward to success in a wild and dangerous region. Possibly in the end, the government may find it advantageous to permit certain lands to be acquired by Europeans, in fee simple; for until this is done the settlement of the country must proceed with extreme slowness. Moreover, mere tenants owning nothing but their improvements, and even these being subject to government appraisement, may be unduly tempted to drain, rather than to develop, the resources of the land they occupy. But the chief aim of the Papuan government is to introduce civilization among the natives, and a slow increase in the European population is of primary necessity to the accomplishment of this result. At present the natives are not taxed, the chief sources of revenue being derived from the customs duties upon imports, the bulk of which are consumed by the Europeans, and this source of income is supplemented by an annual grant of about 25,000 pounds from the Australian Commonwealth, but, due to the duties upon food and necessities, the cost of living is higher than it should be in a new country. Judging, however, from the experience of the English in Fiji and of the Dutch in Java, the natives would be benefited rather than oppressed by a moderate poll tax to be paid in produce, thus developing habits of industry, and in some measure offsetting the evil effects of that insidious apathy which follows upon the sudden abolition of native warfare. Every effort should also he made to encourage and educate the Papuans in the production and sale of manufactured articles. One must regret the loss of many arts and crafts among the primitive peoples of the Pacific, which, if properly fostered under European protection to insure a market and an adequate payment for their wares, would have been a source of revenue and a factor of immeasurable import in developing that self respect and confidence in themselves which the too sudden modification of their social and religious Systems is certain to destroy. The ordinary mission schools are deficient in this respect, devoting their major energies to the "three R's" and to religious instruction, and, while it is pleasing to observe a boy whose father was a cannibal extracting cube roots, one can not but conclude that the acquisition of some money-making trade would be more conducive to his happiness in after life. It is not too much to say that the chief problem in dealing with an erstwhile savage race is to overcome the universal loss of interest and decline in energy which inevitably follows upon the development of that semblance of civilization which is enforced with the advent of the white man. The establishment of manual training schools wherein arts and crafts which may be profitably practiced by the natives as life-professions, is a first essential to the salvation of the race. These schools should and would in no manner interfere with the religious teaching received from missionaries, but would indeed be a most potent factor in the spread of true Christianity among the natives. Whether Christianity be true or false does not affect the case, for the natives are destined to be dominated by Christian peoples, and it primarily essential that they should understand at least the rudiments of Christian ideals and behavior. The realization of the importance of training them to the pursuit of useful arts and trades, which would enable the natives to become self-supporting in the European sense, has been perceived by certain thinkers among the missionaries themselves, and in certain regions efforts are being made the success of which should revolutionize our whole method of dealing with the problem of introducing civilization among a primitive people. Keep their minds active and their hands employed in self-supporting work and their morals and religion will safely fall into accord with Christian standards. Up to the present native education has been left to the devoted efforts of the missionaries, who have more than 10,000 pupils under their charge, but the time is coming when the government should cooperate in establishing trade schools wherein crafts, providing life-vocations to the natives, may be taught. There may be more than 275,000 natives in Papua, but, due to lack of knowledge of the country, the actual number is unknown. Among the mountain fastnesses, defending themselves in tree-houses, one finds a frizzly-headed black negrito-like race hardly more than five feet in height. These are probably remnants of the "pigmy" pre-Dravidian or Negrito-Papuan element, which constituted the most ancient inhabitants of the island and who long ago were driven inland from the coveted coast. The burly negroid Papuans of the Great River deltas of western Papua differ widely from the lithe, active, brown-skinned, mop-headed natives of the eastern half of the southern coast; and Professors Haddon and Seligmann have decided that in eastern New Guinea many Proto-Polynesian, Melanesian and Malayan immigrants have mingled their blood with that of the more primitive Papuans. Thus there are many complexly associated ethnic elements in New Guinea, and often people living less than a hundred miles apart can not understand one another; in fact, each village has its peculiar dialect. Social customs and cultural standards in art and manufacture vary greatly from the same cause, and each tribe has some remarkable individual characteristics. In the Fly-River region, the village consists of a few huge houses with mere stalls for the families, which crowd for defence under the shelter of a single roof. Along the southern side of the eastern end of the island, however, each family has its own little thatched hut, and these are often built for defense upon piling over the sea, reminding one of the manner of life of the prehistoric Swiss-lake dwellers. Nearly 12,000 natives are at present employed by the whites as indentured laborers in Papua, their terms of service ranging from three years, upon agricultural work, to not more than eighteen months in mining. Their wages range from about $1.50 to $5.00 per month, and all payments must be made in the presence of a magistrate and in coin or approved bank notes. At every turn both employer and employed are wisely safeguarded; the native suffering imprisonment for desertion, and the employer being prohibited from getting the blacks into debt, or from treating them harshly or unjustly. Their enlistment must be voluntary and executed in the presence of a magistrate, and, after their term of service, the employer is obliged to return them to their homes. One is impressed with the many manifestations of a fair degree of efficiency on the part of the native laborers, who are really good plantation hands and resourceful sailors. In fact, trade has always been practiced to a considerable extent by the shore tribes, the pottery of the eastern end of the coast being annually exchanged for the sago produced by the natives of the Fly River Delta. It is a picturesque sight to see the large lakatois, or trading canoes, creeping along in the shadow of the palm-fringed shores under the great wall of the mountains, the lakatoi consisting of a raft composed of six or more canoes lashed together side by side, and covered by a platform which bears a thatched hut serving to house the sailors and their wares. The craft is propelled by graceful crescent-shaped lateen sails of pandanus matting and steered by sweeps from the stern. Trading voyages of hundreds of miles are often undertaken, the lakatois starting from the east at the waning of the southeast trade wind in early November and returning a month or two later in the season of the northwest monsoon. The Papuan is both ingenious and industrious when working in his own interest, and with tactful management he becomes a faithful and fairly efficient laborer. Perhaps the most serious defect in the present system of employment in Papua is the usually long interval between payments. The natives are not paid at intervals of less than one month and, often, not until the expiration of their three-year term of service. With almost no knowledge of arithmetic and possessed of a fund which seems large beyond the dreams of avarice, he is practically certain to be cheated by the dishonest tradesmen who flock vulture-like to centers of commercial activity. This evil might be in large measure prevented were the natives to be paid at monthly intervals, for they would then gradually become accustomed to the handling of money and would gain an appreciation of its actual value. Generations must elapse before more than a moderate degree of civilization is developed in Papua, but the foundations are being surely and conservatively laid, and already in the civilized centers natives respect and loyally serve their British friends and masters. In common with many another British colony, the safeguard of Papua lies not in the rifles of the whites, but in the loyal hearts of the natives themselves, and in Papua, as in Fiji, the native constabulary under the leadership of a mere handful of Europeans may be trusted to maintain order in any emergency. As Governor Murray truly states in his interesting book "Papua, or British New Guinea," the most valuable asset the colony possesses is not its all but unexplored mineral wealth or the potential value of its splendid forests and rich soil, but it is the Papuans themselves, and let us add that under the leadership of the high-minded, self-sacrificing and well-trained civil servants of Great Britain the dawn of Papuan civilization is fast breaking into the sunlight of a happiness such as has come to but few of the erstwhile savage races of the earth. Without belittling the nobility of purpose or disregarding the self-sacrificing devotion of the missionary for his task, let us also grant to the civil servant his due share of praise. His duty he also performs in the dangerous wilds of the earth; beset with insidious disease, stifling in unending heat, exiled from home and friends, with suspicious savages around him, he labors with waning strength in that struggle against climate wherein the ultimate ruin of his body is assured. Yet in his heart there lives, growing as years elapse, the English gentleman's ideal of service, and for him it is sufficient that, though he is to be invalided and forgotten even before he dies, yet his will have been one of those rare spirits who have extended to the outer world his mother country's ideal of justice and fair play. CONTACT ELECTRIFICATION AND THE ELECTRIC CURRENT BY PROFESSOR FERNANDO SANFORD STANFORD UNIVERSITY IN a previous paper in this journal, entitled "The Discovery of Contact Electrification" (November, 1913), it was shown that the production of electric charges by the mere contact of two dissimilar metals was first discovered by Rev. Abraham Bennett, in 1789, and that it was verified by a different method by Tiberius Cavallo, in 1795. Meantime, in 1791, Dr. Galvani discovered the twitching of a frog's muscle, due to electrical stimulus. Galvani's discovery was described by himself as follows:[1] [1] Translation from "Makers of Electricity," p 143. 'I had dissected a frog and had prepared it, as in Figure 2 of the fifth plate, and had placed it upon a table on which there was an electric machine, while I set about doing certain other things. The frog was entirely separated from the conductor of the machine, and indeed was at no small distance away from it. While one of those who were assisting me touched lightly and by chance the point of his scalpel to the internal crural nerves of the frog, suddenly all the muscles of its limbs were seen to be so contracted that they seemed to have fallen into tonic convulsions. Another of my assistants, who was making ready to take up certain experiments in electricity with me, seemed to notice that this happened only at the moment when a spark came from the conductor of the machine. He was struck by the novelty of the phenomenon, and immediately spoke to me about it, for I was at the moment occupied with other things and mentally preoccupied. I was at once tempted to repeat the experiment, so as to make clear whatever might be obscure in it. For this purpose I took up the scalpel and moved its point close to one or the other of the crural nerves of the frog, while at the same time one of my assistants elicited sparks from the electric machine. The phenomenon happened exactly as before. Strong contractions took place in every muscle of the limb, and at the very moment when the sparks appeared, the animal was seized as it were with tetanus.' Following this original observation, Galvani made a great many experiments on the effect of electric stimulus upon the nerves of frogs and other animals. He found that the twitching of the frog's muscles could be produced by atmospheric electricity, both at the time of lightning and at other times when no lightning was visible. During these investigations he observed that when the legs of the frog were suspended from an iron railing by a hook through the spinal cord, and when this hook was of some other metal than iron, the muscles would twitch whenever the feet touched the iron railing. He tried out a number of pairs of metals, and found that when the nerve was touched by one metal and the muscle or another point on the nerve was touched by another metal and the two metals were then brought into contact or were connected through another metal or through the human body, the muscles would contract as they would when stimulated by electricity. Galvani concluded that the contraction in this case, as in the earlier experiments, was produced by an electric stimulation, and since the metals seemed to him to serve merely as the conductors of the electric discharge, he concluded that the source of the electricity must be in the tissues of the animal body. This seemed all the more probable since it was known that certain fishes and an electric eel were capable of giving violent electric shocks. This electricity of the eels and fishes had been named animal electricity, and Galvani concluded that all animals were capable of producing this electricity in the tissues of their bodies. He believed this electricity was to be found in various parts of the body, but that it was especially collected in the nerves and muscles. The especial property of this animal electricity seemed to be that it discharged from the nerves into the muscles, or in the contrary direction, and that to effect this discharge it would take the path of least resistance through the metal conductor or through the human body. Since during this discharge the muscle was caused to contract, Galvani concluded that the purpose of this animal electricity was to produce muscular contractions. Galvani seems to have concerned himself principally with the physiological processes which he believed gave rise to the electric charges, but physicists began immediately to seek for other sources of the electricity. The one observation which seemed to offer a definite suggestion as to the possible source of the electrical charge was the fact that, in general two different metals must be used to connect the muscle and nerve before a discharge would take place from the one to the other. This made Galvani's theory that the metals served merely as conductors seem improbable. On the other hand, it was sometimes possible to get the muscular contractions by using a single bent wire or rod to connect the nerve and muscle, especially if the two ends were of different degrees of polish, or if one end was warmer than the other. Volta was apparently the first to suggest that the electricity which seemed to be generated in Galvani's experiments might have its source in the contact of the two metals. Several writers called attention to an apparent relation between Galvani's experiments and a phenomenon announced by J. G. Sulzer, in 1760. Sulzer found that if pieces of lead and silver were placed upon the tongue separately no marked taste was produced by either, but that if while both were on the tongue the metals were brought into contact a strong taste was produced which he compared to the taste of iron vitriol. Here was a case of undoubted stimulation of the nerves of taste by the contact of two metals, and it seemed not improbable that other nerves might be stimulated in the same manner. In the meantime Mr. John Robison had increased the Sulzer effect greatly by building up a pile of pieces of zinc with silver shillings and placing these in contact with the tongue and the cheek. It was the question as to the possibility of producing the electric charge by mere metallic contact which led Cavallo to make his experiments upon contact electrification. Thus Cavallo says in Volume III. of "A Complete Treatise on Electricity," published in 1795: 'The above mentioned singular properties, together with some other facts, which will be mentioned in the sequel induced Mr. Volta, to suspect that possibly in many cases the motions are occasioned by a small quantity of electricity produced by the mere contact of two different metals; though he acknowledges that he by no means comprehends in what manner this can happen. This suspicion being entertained by so eminent a philosopher as Mr. Volta, induced Dr. Lind and myself to attempt some experiment which might verify it; and with this in view we connected together a variety of metallic substances in diverse quantities, and that by means of insulated or not insulated communications; we used Mr Volta's condenser, and likewise a condenser of a new sort; the electrometer employed was of the most sensible sort; and various other contrivances were used, which it will be needless to describe in this place; but we could never obtain the smallest appearance of electricity from those metallic combinations. Yet we can infer to no other conclusion, but that if the mere combination, or contact, of the two metals produces any electricity, the quantity of it in our experiments was too small to he manifested by our instruments.' Later, on page 111 of the same volume, he says: 'After many fruitless attempts, and after having sent to the press the preceding part of this volume, I at last hit upon a method of producing electricity by the action of metallic substances upon one another, and apparently without the interference of electric bodies. I say apparently so, because the air seems to be in a great measure concerned in those experiments, and perhaps the whole effect may be produced by that surrounding medium. But, though the irregular, contradictory, and unaccountable effects observed in these experiments do not as yet furnish any satisfactory theory, and though much is to be attributed to the circumambient air, yet the metallic substances themselves seem to be endowed with properties peculiar to each of them, and it is principally in consequence of those properties that the produced electricity is sometimes positive, at other times negative, and various in its intensity.' Cavallo then proceeds to describe the experiments on contact electrification which were described in the previous paper referred to at the beginning of the article. Cavallo's experiments were evidently made in 1795. In the following year Volta announced the discovery of the electrical current. In a letter written to Gren's Neues Journal der Physik, August, 1796, Volta says: 'The contact of different conductors, particularly the metallic, including pyrites and other minerals as well as charcoal, which I call dry conductors, or of the first class with moist conductors, or conductors of the second class, agitates or disturbs the electric fluid, or gives it a certain impulse. Do not ask in what manner: it is enough that it is a principle and a great principle.' It will be seen that at this stage of his discovery Volta was inclined to attribute tho origin of the current to the contact between the metals and his moist "conductors of the second class," though later in the same article he says it is impossible to tell whether the impulse which sets the current in motion is to be attributed to the contact between the metals themselves or between the two metals and the moist conductor, since either supposition would lead to the same results. Later, as was shown in the previous paper by the present writer Volta came to regard the metallic contact as the cause of the electromotive force. In a letter written to Gren in 1797 and published as a postscript to his letter of August, 1796, Volta says: 'Some new facts, lately discovered, seem to show that the immediate cause which excites the electric fluid, and puts it in motion, whether it be an attraction or a repulsive power, is to be ascribed much rather to the mutual contact of two different metals, than to their contact with moist conductors.' The new facts, "lately discovered," to which Volta attributes his change of view were his repetitions of Bennett's experiments of 1789. Volta apparently thought that the current was not only set up by the contact of the two metals of a pair, but that it was kept up by the mutual action of the metals on each other. He accordingly made no attempt to discover whether any changes took place in his circuit while the current was being generated. The chemical action on his metals and the dissociation in his electrolyte seem to have entirely escaped his attention. At least, he did not attach enough importance to them to mention them anywhere in his description of his apparatus. In the meantime a chemical explanation of the phenomena observed by Galvani had been proposed in 1792 by Fabroni, a physicist of Florence. After discussing the Sulzer phenomenon already mentioned in this paper, Fabroni argues that the peculiar taste caused by bringing the two metals into contact while on the tongue is due to a chemical, rather than to an electrical, action. He then discusses the different chemical behavior of metals when taken singly and when placed in contact with other metals. He says:[2] [2] The following quotations from Fabroni have been translated by the present writer from the German of Ostwald's "Elektrochemie," pp. 103, ff. I have already frequently observed that fluid mercury retains its beautiful metallic luster for a long time when by itself; but as soon as it is amalgamated with any other metal it becomes rapidly dim or oxidized, and in consequence of its continuous oxidation increases in weight. I have preserved pure tin for many years without its changing its silvery luster, while different alloys of this metal which I have prepared for technical purposes have behaved quite otherwise. I have seen in the museum at Cortonne Etrusean inscriptions upon plates of pure lead which are perfectly preserved to this day' although they date from very ancient times; on the other hand, I have found with astonishment in the gallery of Florence that the so-called "piombi" or leaden medallions of different popes, in which tin and possibly some arsenic have been mixed to make them harder and more beautiful, have fallen completely to white powder, or have changed to their oxides, though they were wrapped in paper and preserved in drawers. In the same way I have observed that the alloy which was used for soldering the copper plates upon the movable roof of the observatory at Florence has changed rapidly and in places of contact with the copper plates has gone over into a white oxide. I have heard also in England that the iron nails which were formerly used for fastening the copper plates of the sheathing of ships were attacked on account of contact, and that the holes became enlarged until they would slip over the heads of the nails which held them in position. It seems to me that this is sufficient to show that the metals in these cases exert a mutual influence upon each other, and that to this must be ascribed the cause of the phenomena which they show by their combination or contact. After discussing some of the experiments on nerve stimulation which had been made by Galvani and others, Fabroni argues that these are principally, if not wholly, due to chemical action, and that the undoubted electrical phenomena which sometimes accompany them are not the cause of the muscular contractions. In discussing the nature of the chemical changes produced in two metals by their mutual contact, Fabroni says: 'Since the metals have relationships with each other, the molecules must mutually attract each other as soon as they come into contact. One can not determine the force of this attraction, but I believe it is sufficient to weaken their cohesion so that they become inclined to go into new combinations and to more easily yield to the influence of the weakest solvents.' In order to further show the weakening of cohesion by the contact of two metals, Fabroni describes the results of some experiments which he has made. He says: 'In order to assure myself of the truth of my assumptions, I put into different vessels filled with water: (1) Separate pieces, for example, of gold in one, silver in another, copper in the third, likewise tin, lead, etc. (2) In other similar vessels I put pieces of the same metals in pairs, a more oxidizable and a less oxidizable metal in each pair' but separated from each other by strips of glass (3) Finally, I put in other vessels pairs of different metals which were placed in immediate contact with each other. The first two series suffered no marked change, while in the latter series the more oxidizable metal became visibly covered with oxide in a few instants after the contact was made.' Fabroni found that under the above circumstances his oxidizable metals dissolved in the water, and in some cases salts were formed which crystallized out. He then compares the metals in contact with each other in water with the metals on the tongue when brought into contact, as in Sulzer's experiment, and the two metals touching each other by which different points on a nerve were touched to produce the muscular twitchings in Galvani's experiments, and concludes that the chemical action upon the metals was the same in each case, and that the other phenomena observed must have resulted from this chemical action. It is not strange that when Volta showed later that an electric current passed between the metals in all of tho above cases Fabroni should regard the chemical action which he had previously observed as the cause of this current. Ten years after the publication of Fabroni's original paper, Volta wrote a letter to J. C. Delamethrie which was published in Vol. I of Nicholson's Journal. This letter was written after the chemical changes in the voltaic cell had received a great deal of attention by many experimenters, the most prominent of whom was Davy. To show that Volta's theory as to the source of the current was not affected by these investigations, a quotation from this letter is given below. 'You have requested me to give you an account of the experiments by which I demonstrate, in a convincing manner, what I have always maintained, namely, that the pretended agent, or GALVANIC FLUID, is nothing but common electrical FLUID, and that this fluid is incited and moved by the simple MUTUAL CONTACT OF DIFFERENT CONDUCTORS, particularly the metallic; strewing that two metals of different kinds, connected together, produce already a small quantity of true electricity, the force and kind of which I have determined; that the effects of my new apparatus (which might be termed electromotors), whether consisting of a pile, or in a row of glasses, which have so much excited the attention of philosophers, chemists, and physicians; that these so powerful and marvelous effects are absolutely no more than the sum total of the effects of a series of several similar metallic couples or pairs; and that the chemical phenomena themselves, which are obtained by them, of the decomposition of water and other liquids, the oxidation of metals, &c., are secondary effects; effects, I mean, of this electricity, of this continual current of electrical fluid, which by the above mentioned action of the connected metals, establishes itself as soon as we form a communication between the two extremities of the apparatus, by means of a conducting bow; and when once established, maintains itself, and continues as long as the circuit remains interrupted.'[3] [3] This seems to be a misprint for uninterrupted. Further along in the same letter Volta reiterates his conviction that the contact of the two metals furnishes the true motive power of the current. Thus he says (p. 138): 'As to the rest, the action which excites and gives motion to the electric fluid does not exert itself, as has been erroneously thought, at the contact of the wet substance with the metal, where it exerts so very small an action, that it may be disregarded in comparison with that which takes place, as all my experiments prove, at the place of contact of different metals with each other. Consequently the true element of my electromotive apparatus, of the pile, of cups, and others that may be constructed according to the same principles, is the simple metallic couple, or pair, composed of two different metals, and not a moist substance applied to a metallic one, or inclosed between two different metals, as most philosophers have pretended. The humid strata employed in these complicated apparatus are applied therefore for no other purpose than to effect a mutual communication between all the metallic pairs, each to each, ranged in such a manner as to impel the electric fluid in one direction, or in order to make them communicate, so that there may be no action in a direction contrary to the others.' At the end of the above letter as published in Nicholson's Journal, the editor, William Nicholson, comments at length on Volta's theory of the source of current in the cell and calls attention to the fact that Davy had already made cells by the use of a single metal and two different liquids. At the conclusion of his comments he calls attention to the fact that Bennett and Cavallo had performed experiments with contact electrification prior to Volta's experiments, and says in conclusion, after referring to Bennett, 'This last philosopher, as well as Cavallo, appears to think that different bodies have different attractions or capacities for electricity; but the singular hypothesis of electromotion, or a perpetual current of electricity being produced, by the contact of two metals is, I apprehend, peculiar to Volta.' This peculiar theory of Volta's probably never gained many adherents and was necessarily abandoned as soon as the energy relations of the current were considered, but the controversy as to whether the electrical current or the accompanying chemical changes was the primary phenomenon soon became transferred to a quite different field, viz., to the origin of the electrical charges which Bennett had shown resulted from the contact of different metals. Bennett attempted to account for the phenomena which he had observed on the hypothesis that different substances "have a greater or less affinity with the electric fluid," and Cavallo says: 'I am inclined to suspect that different bodies have different capacities for holding the electric fluid.' Volta reaches a similar conclusion after repeating some of Bennett's experiments. In referring to this decision of Volta as to the origin of the electric charge in contact electrification, Ostwald says: 'We stand here at a point where the most prolific error of Electrochemistry begins, the combating of which has from that time on occupied almost the greater part of the scientific work in this field.' The error, from Ostwald's point of view, lies in the assumption that the transference of electricity from the one metal to the other is a primary phenomenon of metallic contact. He, with many others, including some of the most distinguished physicists and chemists of the past century, regard the electrical transference as a secondary phenomenon resulting from the previous oxidation of one of the metals. Thus Lodge, in discussing the opposite electrification of plates of zinc and copper when brought into contact says: 'The effective cause of the whole phenomenon in either case is the greater affinity of oxygen for zinc rather than copper.' The apparent conflict of opinion between those who hold that the different affinities of the metals for oxygen is the cause of the rearrangement of their electrical charges when brought into contact and those who hold with Bennett and Cavallo that the metals in their natural state have different affinities for the electrical fluid must disappear when we recognize that all affinity, and consequently the affinity for oxygen, must be an electrical attraction. If zinc has an affinity for oxygen, it must be because the zinc is either electropositive or electronegative to oxygen. If it has a greater affinity for oxygen than copper has, then the zinc must be either electropositive or electronegative to copper. This being the case, and both being conductors, it is not surprising that some electricity will flow from one to the other when the two metals are brought into contact. Those writers who attribute the oxidation theory of contact electrification to Fabroni apparently overlook the fact that not oxidation, but the weakening of the cohesion of at least one of the metals due to their contact, was the primary phenomenon in Fabroni's theory. When this is remembered, it is seen that the observations of Bennett and Fabroni, instead of furnishing arguments for two conflicting theories, actually serve, as all true scientific observations must, to supplement each other. Thus we now know that cohesion or affinity is an electrical attraction between the atoms or molecules of a body. The only known methods of changing the electrical attraction between two bodies whose distances and directions from other bodies remain constant is by varying the magnitude of their charges or by changing the specific inductive capacity of the medium between them. Bennett observed that when two pieces of different metal in their normal electrical condition are placed in contact, there is a redistribution of the charges of their surface atoms. Fabroni observed under the same conditions a change in the surface cohesion of the two metals. To the present writer this seems the actual sequence of phenomena, viz., a redistribution of the charges of the surface atoms of the metals, a consequent change in surface cohesion and a resultant oxidation of one of the metals. ON CERTAIN RESEMBLANCES BETWEEN THE EARTH AND A BUTTERNUT BY PROFESSOR A, C. LANE TUFTS COLLEGE THE drama of the earth's history consists in the struggle between the forces of uplift and the forces of degradation. The forces of uplift are mainly the outward expression of the inner energy and heat of the earth, whether they be the volcano belching its ashes thousands of meters into the air, or the earthquake, with the attendant crack or fault in the earth's crust, leading to a sudden displacement, and sending, far and wide, a death-dealing shock, or those mountain-building actions, which, though they may be as gentle and gradual as might be produced by the breathing of mother earth and the uplifting of her bosom thereby, nevertheless, end in the huge folds of our mountain ranges. Against these, there are always working the forces of degradation--the slow rotting of weathering caused by the direct chemical action of the moist atmosphere or the alternation of hot and cold which crumbles rocks far above the line where rain never falls. Once the rock is rotten and decayed, it yields readily to the forces of degradation, which drag it down--the beating of the rain, the rush of the avalanche or of the landslide, the tumult of the torrent, the quieter action of the muddy river in its lower reaches or the mighty glacier which transfers fine and coarse material alike toward the sea. These actions are always going on. Are they always equally balanced, or are there periods when the forces of elevation are more active, the forces of degradation not so powerful, as against other times in which the forces of degradation alone are at work? If there is inequality in the balance and struggle of these contending forces, the great periods or acts in the geologic drama might thus be marked off as Chamberlin suggests. Newbery, Schuchert and others have pointed out that there seem to have been great cycles of sedimentation which may be interpreted as due to the alternate success, first of the factors of elevation, then of those of degradation. Suppose, for instance, that there has been an epoch of elevation, that mountain chains have been lifted far into the sky and volcanoes have sent their floods of lava forth, and fault-scarped cliffs run across the landscape and that then, for a while, the forces of elevation cease their work. Little by little, the mountains will be worn down to a surface of less and less relief, approaching a plain as a hyperbola approaches its asymptote--a surface which W. M. Davis has called peneplain. But where will the material thus worn go? Into the sea. Going into the ocean it will raise the level of the sea slowly but surely. At present, for every four feet of elevation taken off the land, there will be something like one foot rise of the ocean level, and this rise may take only thirty thousand years--a long time in human history, but not so long in the history of the earth. All the time, then, that the forces of the atmosphere are wearing down the surface of the earth to the sea level the sea is rising and its waves are producing a plain of marine denudation which rises slowly to meet the peneplain which is produced by degradation. In the beginning of this cycle, where the forces of degradation have their own way, coarse material may be brought down by torrents from the mountains, and the glaciers, which find their breeding place in these high elevations, may drag down and deposit huge masses of boulder clay. But, little by little as the mountains are lowered, the sediments derived from them will become finer and finer and glaciers will find fewer and fewer sources. Not only that, but the growth of seas extending over the continents will tend to change the climate, we shall have a moister, more insular climate, we shall have a greater surface of evaporation, and thus, on the whole, a more equable temperature throughout the world. We know that, at present, the extremes of cold and hot are found far within the interior of the continents. Continental climates are the climates of extremes, and on the whole extremes are hurtful to life. So then as the forces of degradation tend to lower the continents beneath the sea level glaciers and deserts and desert deposits alike must also disappear. Vegetation will clothe the earth, and marine life swarm in the shallow seas of the broadening continental shelf. Under the mantle of vegetation, mechanical erosion will be less, that is, the breaking up of rocks into small pieces without any very great change, but the rich soil will be charged with carbon dioxide, and chemical activity will still go on. Rivers will still contain carbonates, even though they carry very little mud, and in the oceans the corals and similar living forms will deposit the burden of lime brought into the sea by the rivers. Thus, if forces of degradation have their own way, in time there will be a gradual change in dominant character, from coarse sediments to fine, from rocks which are simply crumbled debris to rocks that are the product of chemical decay and sorting, so that we have the lime deposited as limestone in one place and the alumina and silica, in another. We shall have a change from local deposits, marine on the edges of large continents, or land deposits, very often coarse, with fossils few and far between, to rocks in which marine deposits will spread far over the present land in which will appear more traces of that life that crowded in the shallow warm seas which form on the flooded continents. We shall have a transition from deposits which may be largely formed on the surface of the continents. lakes, rivers, salt beds and gypsum beds, due to the drying up of such lakes and the wind-blown deposits of the steppes, to deposits which are almost wholly marine. Now, I need not say (to those who are familiar with geology) that we have indications of just such alternations in times passed. There are limestones abounding in fossils, with a cosmopolitan life very wide spread to be recognized in every continent, such as used to be known as the Trenton limestone, the mountain limestone, the chalk. Perhaps every proper system and period should be marked by such a limestone in the middle. The time classed as late Permian and Triassic on the other hand was one of uplift, disturbance, volcanic action and extreme climates, which gave us the traps of Mt. Tom, the Palisades of the Hudson, the bold scenery of the Bay of Fundy and the gypsum and red beds which are generally supposed to be quite largely formed beneath the air and beds of tillite formed beneath glaciers. Then in the times succeeding, in many parts of the world, degrading forces were more effective than uplifting so that the mountains became lower, and the seas extended farther over the continents. Then the prevalence of lime sediments was so great that the "chalk" was thought to be characteristic everywhere. And about the time the "chalk" the land was reduced to a peneplain. A similar cycle may be traced from the Keweenawan rocks to the group of limestones so widespread over the North American continent and so full of fossils, which to older geologists and oil drillers have been known, in a broad way, as Trenton. All this introduces a question--to which I wish to suggest an answer--How is it that these cycles came to be? Were the outer rock crust of the earth perfectly smooth the oceans would cover it to the depths of thousands of feet and it is only by the wrinkling of such a crust that any part of it appears above the ocean. If the earth had a cool thin crust upon a hot fluid interior, and that thin crust were able to sustain itself during geologic ages so that the shrinkage should accumulate within, until finally collapse came, giving an era of uplift, it is obvious that we could account for such cycles. There is very clear evidence that the outermost layer of the earth's crust is but a thin shell like the outer shuck or exocarp of a butternut, so thin that it is not at all possible that it can sustain itself for more than a hundred miles or so, or for more than a very few years at the outside. Hayford's[1] investigations are the latest that show that the continents project because, on the whole, they are lighter, they float, that is, above the level of the oceans because there is a mass of lighter rock below, like an iceberg in the sea. Here the likeness between nut and earth fails and it would be more like the earth if the outer shuck were thicker in certain large areas. If this extra lightness or "isostatic compensation" is equally distributed, Hayford finds[2] that the most probable value of the limiting depth is 70 (113 km.) miles, and practically certain that it is somewhere between 50 (80 km.) and 100 (150 km.) miles; if, on the other hand, this compensation is uniformly distributed through a stratum 10 (16 km.) miles thick at the bottom of the crust so that there is a bulging of the crust down into a heavier layer below to balance the projection of the mountains above, as I think much more likely, then the most probable depth for the bottom of the outer layer is 37 (60 km.) miles. This layer is much thinner than the outer layer of the figure and is supposed to yield to weight placed as, though more slowly than, new thin ice bends beneath the skater. [1] The figure of the earth and isostasy from measurements in the U.S. Dept. of Commerce and Labor, 1909, p. 175. [2] loc. cit., p. 175. There are a number of facts which support this so-called theory of isostasy, according to which the crust of the earth is not capable of sustaining any very great weight, though it may be at the outside rigid, but is itself essentially like a flexible membrane resting on a layer of viscous fluid. However viscous this fluid may be and rigid to transitory quickly shifting strains like those produced by the earth's rotation, it does NOT REMAIN AT REST in a state of strain (at any rate if this strain passes limits which are relatively quite low). Not only are, according to Hayford's observations, the inequalities of the North American continent compensated for by lighter material below, so that the plumb- bob deflections are only one
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