Let me pass from these generalities, which have been suggested to my mind by the consideration of some of the scientific changes that have taken place during the last hundred years, and let me refer briefly to some of the changes and advances which appear to me to be most characteristic of that period. It is not that I am concerned with a selection of the most important researches of the period. Estimates of relative importance are often little more than half-concealed expressions of individual preferences or personal enthusiasms; and though each enthusiastic worker, if quite frank in expressing his opinion, would declare his own subject to be of supreme importance, he would agree to a compromise that the divergence between the different subjects is now so wide as to have destroyed any common measure of comparison. My concern is rather with changes, and with tendencies where these can be discerned. The growth of astronomy has already occupied so large a share of my remarks that few more words can be spared here. Not less, but more, remarkable than the preceding centuries in the actual exploration of the heavens, which has been facilitated so much by the improvements in instruments and is reinforced to such effect by the cooperation of an ever-growing band of American astronomers, it has seen a new astronomy occupy regions undreamt of in the older days. New methods have supplemented the old; spectroscopy has developed a science of physics within astronomy; and the unastronomical brain reels at the contents of the photographic chart of the heavens which is now being constructed by international cooperation and will, when completed, attempt to map ten million stars (more or less) for the human eye. Nor has the progress of physics, alike on the mathematical side and the experimental side, been less remarkable or more restricted than that of astronomy. The elaborate and occasionally fantastic theories of the eighteenth century, in such subjects as light, heat, even as to matter itself, were rejected in favor of simpler and more comprehensive theories. There was one stage when it seemed as if the mathematical physicists were gradually overtaking the experimental physicists; but the discoveries in electricity begun by Faraday left the mathematicians far behind. Much has been done towards the old duty, ever insistent, of ́explaining new phenomena; and the names of Maxwell, Weber, Neumann, and Hertz need only to be mentioned in order to suggest the progress that has been made in one subject alone. We need not hesitate to let our thoughts couple, with the great physicists of the century, the leaders of that brilliant band of workers upon the properties of matter who carry us on from wonder to wonder with the passage of each successive year. Further, it has been an age when technical applications have marched at a marvelous pace. So great has been their growth that we are apt to forget their comparative youth; yet it was only the middle of the century which saw the awakening from what now might be regarded as the dark ages. Nor is the field of possible application nearing exhaustion: on the contrary, it seems to be increasing by reason of new discoveries in pure science that yet will find some beneficent outcome in practice. Invisible rays and wireless telegraphy may be cited as instances that are occupying present activities, not to speak of radium, the unfolding of whose future is watched by eager minds. One gap, indeed, in this subject strikes me. There are great histories of mathematics and great histories of astronomy; I can find no history of physics on the grand scale. Some serviceable manuals there are, as well as monographs on particular topics; But, as you hear me thus referring to astronomy and to physics, some of you may think of the old Roman proverb which made the cobbler not to look above his last; so I take the opportunity of referring very briefly to my own subject. One of the features of the century has been the continued development of mathematics. As a means of calculation the subject was developed as widely during the earlier portion of the century as during the preceding century; it soon began to show signs of emergence as an independent science, and the later part of the century has witnessed the emancipation of pure mathematics. It was pointed out, in connection with the growth of theoretical astronomy, that mathematics developed in the direction of its application to that subject. When the wonderful school of French physicists, composed of Monge, Carnot, Fourier, Poisson, Poinsot, Ampère and Fresnel (to mention only some names), together with Gauss, Kirchhoff and von Helmholtz in Germany, and Ivory, Green, Stokes, Maxwell and others in England, applied their mathematics to various branches of physics, for the most part its development was that of an ancil lary subject. The result is the superb body of knowledge that may be summarized under the title of mathematical physics '; but the final interest is the interest of physics, though the construction has been the service of mathematics. Moreover, this tendency was deliberate, and was avowed in no uncertain tone. Thus Fourier could praise the utility of mathematics by declaring that there was no language more universal or simpler, more free from errors or obscurity, more worthy of expressing the unchanging relations of natural entities'; in a burst of enthusiasm he declares that, from the point of view he had indicated, mathematical analysis is as wide as nature herself,' and it increases and grows incessantly stronger amid all the changes and errors of the human mind.' Mathematicians might almost blush with conscious pleasure at such a laudation of their subject from such a quarter, though it errs by both excess and defect; but the exultation of spirit need not last long. The same authority, when officially expounding to the French Academy the work of Jacobi and of Abel upon elliptic functions, expressed his chilling opinion (it had nothing to do with the case) that 'the questions of natural philosophy, which have the mathemathical study of all important phenomena for their aim, are also a worthy and principal subject for the meditations of geometers. It is to be desired that those persons who are best fitted to improve the science of calculation should direct their labors to these important applications.' Abel was soon to pass beyond the range of admonition; but Jacobi, in a private letter to Legendre, protested that the scope of the science was not to be limited to the explanation of natural phenomena. I have not quoted these extracts by way of even hint of reproach against the author of such a wonderful creation as Fourier's analytical theory of heat; his estimate could have been justified on a merely historical review of the circumstances of his own time and of past times; and I am not sure that his estimate has not its exponents at the present day. But all history shows that new discoveries and new methods can spread to issues wider than those of their origins, and that it is almost a duty of human intelligence to recognize this possibility in the domain of progressive studies. The fact is that mathematical physics and pure mathematics have given much to each other in the past and will give much to each other in the future; in doing so, they will take harmonized action in furthering the progress of knowledge. But neither science must pretend to absorb the activity of the other. It is almost an irony of circumstance that a theorem, initiated by Fourier in the treatise just mentioned, has given rise to a vast amount of discussion and attention, which, while of supreme value in the development of one branch of pure mathematics, have hitherto offered little, if anything, by way of added explanation of natural phe nomena. The century that has gone has witnessed a wonderful development of pure mathematics. The bead-roll of names in that science-Gauss; Abel, Jacobi; Cauchy, Riemann, Weierstrass, Hermite; Cayley, Sylvester; Lobatchewsky, Lie-will on only the merest recollection of the work with which their names are associated show that an age has been reached where the development of human thought is deemed as worthy a scientific occupation of the human mind as the most profound study of the phenomena of the material universe. The last feature of the century that will be mentioned has been the increase in the number of subjects, apparently dissimilar from one another, which are now being made to use mathematics to some extent. Perhaps the most surprising is the application of mathematics to the domain of pure thought; this was effected by George Boole in his treatise Laws of Thought,' published in 1854; and though the developments have passed considerably beyond Boole's researches, his work is one of those classics that mark a new departure. Political economy, on the initiative of Cournot and Jevons, has begun to employ symbols and to develop the graphical methods; but there the present use seems to be one of suggestive record and expression, rather than of positive construction. Chemistry, in a modern spirit, is stretching out into mathematical theories; Willard Gibbs, in his memoir on the equilibrium of chemical systems, has led the way; and, though his way is a path which chemists find strewn with the thorns of analysis, his work has rendered, incidentally, a real service in coordinating experimental results belonging to physics and to chemistry. A new and generalized theory of statistics is being constructed; and a school has grown up which is applying them to biological phenomena. Its activity, however, has not yet met with the sympathetic good-will of all the pure biologists; and those who remember the quality of the discussion that took place last year at Cambridge between the biometricians and some of the biologists will agree that, if the new school should languish, it will not be for want of the tonic of criticism. If I have dealt with the past history of some of the sciences with which our section is concerned, and have chosen particular epochs in that history with the aim of concentrating your attention upon them, you will hardly expect me to plunge into the future. Being neither a prophet nor the son of a prophet, not being possessed of the knowledge which enabled Halley to don the prophet's mantle with confidence, I shall venture upon no prophecy even so cautious as Bacon's-'As for the mixed mathematics, I may only make this prediction, that there can not fail to be more kinds of them as nature grows further disclosed '-a declaration that is sage enough, though a trifle lacking in precision. Prophecy, unless based upon confident knowledge, has passed out of vogue, except perhaps in controversial politics; even in that domain, it is helpless to secure its own fulfilment. Let me rather exercise the privilege of one who is not entirely unfamiliar with the practice of geometry, and let me draw the proverbial line before indulgence in prophetic estimates. The names that have flitted through my remarks, the discoveries and the places associated with those names, definitely indicate that, notwithstanding all appearance of divergence and in spite of scattered isolation, the sum of human knowledge, which is an inheritance common to us all, grows silently, sometimes slowly, yet (as we hope) safely and surely, through the ages. You who are in South Africa have made an honorable and an honored contribution to that growing knowledge, conspicuously in your astronomy and through a brilliant succession of astronomers. Here, not as an individual, but as a representative officer of our brotherhood in the British Association, I can offer you no better wish than that you may produce some men of genius and a multitude of able workers who, by their researches in our sciences, may add to the fame of your country and will contribute to the intellectual progress of the world. A. R. FORSYTH. SCIENTIFIC BOOKS. Catalogue of the Lepidoptera Phalene in the British Museum, London. Vol. IV., Noctuida (part), 1903; Vol. V., Noctuidae (continued), 1905. By Sir GEORGE F. HAMPSON, Bart. This is a continuation of the monographs of the moths of the world, of which Vol. III. was noticed in SCIENCE, N. S., XV., 99, 1901. A notice of Vol. IV. will be found in the Canadian Entomologist, XXXVI., 27, 1904. Volume V., now before us, consists of 634 pages and treats of 2,073 species of Noctuidæ, comprising the subfamily Hadeninæ. These moths have unspined hind tibiæ and hairy eyes, and are familiar to us under the name Mamestra and allies. But these familiar names are again largely changed, unavoidably, no doubt, but we fear that the changes are not permanent. Even if subsequent authors can be induced to respect Sir George Hampson's selections of the types of the older genera, we doubt if he will be generally followed in defining no genera on secondary sexual characters. This is done generally in other families of Lepidoptera and the characters prove very useful. We think some of the genera as used in the volume before us would stand subdivision, Polia, for example, which contains 209 species. This would save the old genus Mamestra, which now sinks as a synonym of Polia. These remarks apply to the other volumes as well and are a criticism on the general system adopted. It is not to be expected that the system could be changed during the progress of the work. A number of our North American species, particularly those recently described, sink as synonyms. This is mostly perfectly justified, as there has been a tendency recently to describe too many forms as species in the Noctuidæ. This tendency has received a just rebuke. On page 24, Scotogramma is marked as a 'new' genus, no doubt by an oversight. On page 178 all the forms of comis and olivacea fall together into the synonymy. I believe this is going a little too far, as I think there can be distinguished two species, though closely allied. Otherwise my contention about these forms is sustained. On page 267 the name Chabuata velutina is used. It should be Chabuata lutina. Velutina was preoccupied when described and the author very properly changed the name. The fact that Hampson has removed it to another genus does not invalidate the change, which was proper when made. He has here violated the rule Once a synonym, always a synonym.' Page 366. The distribution of the genus Morrisonia is remarkable. Twenty-eight species are known, twenty-two in New Zealand, six in the United States, and none anywhere else in the world. Of the United States species, five are eastern, only one being western (Arizona). Morrison's species peracuta, described as from the United States, is removed to the next genus and becomes a synonym of a New Zealand species, the United States locality being regarded as erroneous. Page 403, my species Perigrapha achsha is omitted (Can. Ent., XXXVI., 32, 1904). On page 596, Leucania rubripallens is credited to Kaslo, British Columbia. I did not find the species there (Proc. U. S. Nat. Mus., XXVII., 863, 1894), and I believe that this is a case of misidentification. The synoptic table on page 594 is bad, the contrasts given under a and b3 are variable and valueless. L. rubripallens separates from oxygale and minorata by the redder color of the fore wings only, not by the degree of black shading on the hind wings. It occurs in the dry regions of Colorado and Utah and I believe does not occur in the wet wooded district of Kaslo. On page 610, Himella infidelis is made synonymous with Eriopyga conar and marked non descr.' I do not object to the synonym, even if I do not agree to it, but the species certainly was described (Can Ent., XXXVI., 32, 1904). HARRISON G. DYAR. SCIENTIFIC JOURNALS AND ARTICLES. THE leading article in the June number of the American Geologist is entitled 'The Fossil Turtles of the Bridger Basin,' by O. P. Hay, who states that hitherto geologists Cope, Powell, Emerson and King considered these beds as lake deposits, but his own conclusion is that they have been made almost wholly through river action.' Professor S. W. Williston says, concluding his article On the Lansing Man,' 'I am only confident that the skeleton dates from Pleistocene times-and is old.' Professor Warren Upham contributes an article on the 'Age of the St. Croix Dalles,' and G. A. Waring one on 'The Pegmatyte Veins of Pala, San Diego County, California,' which is illustrated by five plates and two figures. Professor J. A. Bownocker in discussing The Salt Deposits of Northeastern Ohio,' concludes that Ohio contains enough salt to supply the entire country for an indefinite period.' A paper on 'Mineralogical Synonyms' is inserted, taken from the Mineralogical Magazine for May. The number concludes with an interesting editorial by Dr. G. P. Merrill on The New Building for the National Museum, at Washington, D. C.,' which is illustrated by a plate presenting the central plan. SOCIETIES AND ACADEMIES. CLEMSON COLLEGE SCIENCE CLUB. THE 54th regular meeting of the club was held in the lecture room of the electrical laboratory, April 28, at 8 P.M. It was the occasion of the ninth annual meeting and banquet. There were present, in addition to the regular members of the club, delegates from other colleges in South Carolina and from the U. S. Department of Agriculture. The program consisted of numbers taken from the preceding programs of the club during the current year, and an informal address on certain phases of agricultural education by Assistant Secretary of Agriculture W. H. Hays. After the regular meeting, the annual banquet was served in the new museum in agricultural hall, and the banquet was made the occasion of the dedication of the museum. The 55th regular meeting of the club was held in the lecture room of the electrical laboratory at 8:30 P.M., May 19. Professor J. S. Newman, under the title of Fifty Years of Agriculture,' discussed the advances in practical agriculture within that time, taking a somewhat pessimistic attitude in regard to what had actually been accomplshed. Professor F. T. Dargan, under the title of An Indescribed Method of Demonstrating Horizontal Objects,' made a demonstration of his |