It is a matter of measurement that but one fourth of the water in the Niagara River passes over the American Falls. The sill of the falls is ten feet higher on the American side than on the Canadian. How easily the water is driven entirely out of the American channel is seen by the ice dams of the past few years, which, gorging the stream from the upper end of Goat Island to the American side, have turned the water from that channel so that one can cross the bed of the river dry-shod. Let then, from one fourth to one third of the water be permanently abstracted from the river, and the American Falls will be permanently dry. The production of power actual and immediately contemplated by the five companies within their charters will consume 48,400/224,000 of the water, or 1/5 – With the estimated abstraction of water by the sixth (American) company this fraction becomes 58,400/224,000 or 1/4-. Should the proposed additional Canadian plans be effected the proportion will become 88,396/224,000 or 1/3. In any one of these cases the danger limit is reached and the perpetuity of the American Falls now hangs by the slender thread of improbability that these companies shall produce to their statutory limitations or find a market for their product.

It is authentically stated that 800,000 tourists visit Niagara annually, bringing an enormous revenue to the place. As soon as the world learns that New York and Canada have shorn this famous place of its beauties, this source of industrial prosperity will be gone. While these magnificent schemes of power development are putting to shame a sentiment of proper pride which should be national rather than local, unlimited horsepower lies idle in the region where these companies hope to find their market and in the development of this none of the finer manifestations of natural power and none of the finer sentiments of mankind would be assailed.

The address was a strong presentation of the subject and the press of the city joined in the protest against the destruction of the falls. J. E. KIRKWOOD, Corresponding Secretary.

DISCUSSION AND CORRESPONDENCE.

CONSULTING EXPERTS IN LIBRARIES.

TO THE EDITOR OF SCIENCE: Dr. Francis B. Sumner's letter, published in SCIENCE, January 13, seems to offer an appropriate opportunity for calling attention to certain noteworthy developments at the Library of Congress during the administration of Dr. Herbert Putnam. Dr. Sumner urges the desirability of employing, in connection with one. of our great libraries, a staff of consulting experts, men of the rank of college professors, whose duty it should be to furnish definite bits of information in response to legitimate questions, or, at least, to guide the seeker on his way *** the establishment of a sort of human encyclopedia as an adjunct to the library.'

While this ideal has not yet been attained at the Library of Congress, a remarkable development in this direction has taken place during the last few years. It is the function

of the Division of Bibliography, established in 1900, not only to prepare and publish lists of references on special topics, principally those of current political interest, but also to supply bibliographical information in reply to inquiries received by mail. The reference work of this character has been mainly in the fields of social and political science and history.

As, however, the collection of scientific literature has recently been reclassified and is now in process of being recatalogued, it has become possible to undertake similar work in science. There are on the staff of the library at the present time several specialists representing different sciences, and it is always possible to consult others associated with various branches of the government service. Furthermore, it being part of the policy of the Librarian of Congress to make the collection of bibliographies, indexes, library catalogues, etc., as complete as possible, unusual resources in the way of bibliographical tools are available at the library. A Science Section of the library, in charge of the undersigned, has accordingly been organized recently and one of its functions is to carry on the reference work in this field, both for investigators at the scientific bureaus in Wash

ington and in answer to legitimate inquiries by mail.

Under these circumstances it seems that the facilities now offered by the Library of Congress meet the need indicated in Dr. Sumner's letter to a very considerable extent, and further advances in this direction will occur if it appears that valuable service can be rendered.

I conclude by inviting the readers of SCIENCE to make use of these new facilities whenever the library resources to which they have access are inadequate to the needs of the investigations which they have in hand. Communications should be addressed to the Librarian of Congress, and should be marked 'Science Section if they are inquiries referring to the mathematical, physical or natural sciences. J. DAVID THOMPSON.

THE STORAGE OF MICROSCOPIC SLIDES.

TO THE EDITOR OF SCIENCE: In your issue of December 30 you published an article by C. L. Marlatt, of the U. S. Department of Agriculture, describing a method of storing and indexing microscopic slides.

The Bausch and Lomb Optical Company have designed and are selling an excellent cabinet with card system which has all the advantages claimed by Mr. Marlatt for his and lacking only the envelopes, which I can not but think must be somewhat inconvenient.

These cabinets are made in three sizes, holding 500, 1,500 and 3,000 slides respectively. Tiers of trays, each running in its own groove, are constructed to take slides of various sizes. At the bottom are drawers (one, two or three) containing separate cards for every slide, on each of which is printed a form for registering the slide: Tray No.-Series No.-Name of Slide-Stain-Mounted in- and two lines for other data. There are also printed guide cards from A to Z.

The objects being recorded on separate cards, the removal of slides necessitates simply the removal of its corresponding card, while the addition of slides requires only the filling out and insertion of new cards. fication thus, it will be seen, becomes exceedingly simple. The slides may be rearranged

Classi

and the collection increased or diminished with the least possible amount of trouble. JOSEPHINE SHATZ.

ROCHESTER, N. Y., January 8, 1905.

SPECIAL ARTICLES.

DOPPLER'S PRINCIPLE AND LIGHT-BEATS. THERE is a beautiful lecture experiment in illustration of Doppler's principle due, I believe, to Koenig. A vibrating tuning fork of high pitch, say 2,000 vibrations per second, is moved to and fro near, and at right angles to, a reflecting wall. The waves coming from the fork and (virtually) from its image back of the wall are changed in length by the opposite motions of fork and image with the result that very audible beats are heard. With a fork of the pitch mentioned, a speed of three feet per second gives beats at the rate of about eleven per second. Although special forks are made for this experiment, they are quite unnecessary. An ordinary C 512 fork of Koenig's pattern gives a very shrill tone when strongly bowed near the shank and answers the purpose admirably. If the fork is held stationary and the reflecting surface is moved, the effect is the same on account of the motion of the fork's image.

Attempts to secure visible beats by means of light waves of slightly different wave-length have met with no success, partly on account of rapid changes of phase, and partly because of the difficulty of securing two sources whose vibration frequencies are nearly enough equal. Thus if we assume (what is most likely not true) that the failure to observe interference fringes with differences of path greater than, say, 30 cm. indicates a change of phase, this would indicate 10° or more changes of phase per second. On the other hand, should we take the two D lines as sources there would be about 1012 beats per second. It is evidently almost hopeless to attempt to secure visible light-beats in this manner. If we consider Doppler's effect, however, the case is quite otherwise. The second form of Koenig's experiment, viz., that in which the reflector is moved, is in principle almost exactly analogous to Professor Michelson's interferometer.

NOTE ON THE BROAD WHITE FISH.

IN the Proceedings of the American Philosophical Society of Philadelphia, XLIII., 1904, p. 451, plates VIII. and IX., I have wrongly identified the broad white fish, or Coregonus kennicotti Jordan and Gilbert, as the humpback, or Coregonus nelsonii Bean. My error was due largely to lack of material, ignorance of the species from autopsy, and the fact, as I have since discovered, that C. nelsonii does not always exhibit the well-developed hump like that of the type. Possibly when the Siberian forms are carefully studied the nomenclatures of these fishes will be more stable.

HENRY W. FOWLER. ACADEMY OF NATURAL SCIENCES, PHILADELPHIA, February 5, 1905.

RECENT ZOOPALEONTOLOGY.* DURING the past thirteen years great advances have been made in our knowledge of the ancient mammalian life of North America, especially through the explorations in the Rocky Mountain region carried on by the Carnegie, Field Columbian and American Natural History Museums. The long Tertiary period has been clearly subdivided into a series of stages and substages. This enables paleontologists to record more accurately than ever before the time of arrival and departure of the larger and smaller quadrupeds from North and South America, Asia, Europe, Africa, and to determine more precisely when the connection of North and South America was interrupted by a gulf flowing between the Atlantic and Pacific Oceans, and when the connection was again made by the elevation

Abstract of a lecture delivered by Professor Osborn before the Society of Naturalists at the Philadelphia meeting.

of the Isthmus of Panama; this demonstrates also that a very much closer connection existed between the animal life of Europe and of North America through continuous intermigration over the broad land area now submerged beneath the Behring Straits. A series of six world maps prepared by Dr. W. D. Matthew clearly exhibit this submergence and emergence of the isthmuses between these great continents.

Of especial interest is the recent discovery by the Geological Survey of Egypt that the whole race of mastodons and elephants originated in Africa, entered Europe in the middle of the Tertiary and soon afterward found their way into North America and somewhat later into South America. We have now been able to fix very positively the date of actual arrival of these animals in North America. It appears probable that successive waves of migrations of European and Asiatic species of elephants and mammoths came to this country. In the meantime there survived here from one of the earliest African migrants the eastern American forest mastodon which lived until comparatively recent times.

The theory of multiple races or polyphyletic evolution not only of elephants but of horses, rhinoceroses, camels and titanotheres appears to be clearly established through these recent discoveries. It was formerly believed, for example, that the modern horse had a single line of ancestors extending back into the Eocene period; now it appears that in North America there were always four to six entirely different varieties of the horse family living contemporaneously, including slow-moving, forest-living horses with broader feet, and very swift plains-living horses with narrow feet fashioned more like the deer. Intermediate between these arose the variety which survived and gave rise to the true modern horse. Furthermore, it appears that the modern horses separated from the asses and zebras at a much more remote period than has been generally supposed, and we are now endeavoring to ascertain accurately when this separation occurred.

The same discovery of multiple races has been made among the rhinoceroses. In Eu

rope and in North America instead of forming a single line of evolution there were at least seven or eight nearly contemporary but distinct lines of rhinoceros succession, some of which can be traced back as far as the base of the middle Tertiary. The truly American rhinoceroses which appear to have branched out into several water-living, forest-living and plains-living types, were reinforced by the sudden appearance of the extremely shortlimbed rhinoceroses which had evolved in Europe and came over to this country simultaneously with the earliest elephants or mastodons.

Another remarkable feature of this law of multiple evolution is that even where these varieties have evolved quite separately and independently, they still have inherited from remote common ancestors certain tendencies or potentialities of evolution which were latent but not expressed in the ancestral forms but which find a more or less simultaneous expression in the derived forms. Thus, among the rhinoceroses and titanotheres the rudiments of horns begin to appear more or less simultaneously in several of these multiple independent races or varieties, indicating a hereditary predisposition toward the development of certain organs quite unsuspected in the earlier evolutionary writings of Lamarck and Darwin. This predisposition to evolve certain structures tends to establish the idea that the laws of development are not controlled solely by the survival of the fittest as according to the original Darwinian theory, nor by the inherited effects of use and disuse as according to the Lamack-Spencer theory, but represent the budding out or expression of certain innate or inherited ancestral tendencies.

Among the greatest surprises in recent discovery has been the finding of armadillo-like edentates in the Rocky Mountain region near Ft. Bridger, Wyo., from rocks of the lower Tertiary period. These armadillos certainly bore a leathery if not a bony shield. Some ossicles indicating the presence of the bony shield are reported to be present in the collections of the Yale Museum; the remains thus far found by the American Museum exploring parties show a provision for the shield in the

structure of the backbone but do not exhibit the bony elements of the shield itself.

Almost equally surprising results of ten years' exploration are the tracing back of the dog family into the Lower Eocene, of the sabertooth tiger family into the Middle Eocene, of the camel family into the Upper Eocene, of the hedge-hogs (now extinct in this country) into the Lower Oligocene, of the raccoons into the Lower Miocene. The camel family, like the horses and the rhinoceroses, branched out into a great many varieties, short- and long-limbed, most remarkable among the latter being the giraffe-camel (Alticamelus), which, although a true camel, was closely similar in build to the giraffe. With these discoveries the names of Scott, Wortman and Matthew are honorably associated.

It has long been known that the deer, bear. moose, the oxen and sheep families did not appear in this country until very late in geological times, shortly before the Ice Age.

Among the many difficult and still unsolved problems is the cause of the total extinction of the horse in North and South America while it survived and multiplied in Europe. Asia and Africa. Just before the time of the extinction of the horse, America exhibited the greatest beauty and variety in the development of this family. As studied by Gidley, there were horses exceeding in size the enormous Percherons of to-day and there were also varieties smaller than the most diminutive Shetlands. Yet with all this wide range of variation all became extinct.

The elephants also exhibited three great varieties, the true mammoth (E. primigenius) to the north, the Columbian elephant in the central states, and the gigantic Imperial mammoth to the south, forms shown to be quite distinct by Lucas and undoubtedly adapted to various kinds of climate; yet all died out with the great wave of death which swept off the camels, horses and the giant South American sloths, just before or during the first advance of the Glacial period. H. F. O.

SCIENTIFIC NOTES AND NEWS. THE senate of the University of Edinburgh has voted to confer its honorary doctorate of

laws on Dr. Alexander Graham Bell, of Washington, and on Dr. W. W. Keen, professor of surgery at Jefferson Medical College, Philadelphia.

DR. S. WEIR MITCHELL, the eminent physiologist, physician and author, celebrated his seventy-fifth birthday on February 15. Dr. Weir Mitchell will present candidates for honorary degrees at the celebration of the University of Pennsylvania on February 22. Degrees will be conferred on President Roosevelt and on the Emperor of Germany.

On the occasion of the opening of the new public health laboratory of the Victoria University, Manchester, honorary doctorates of science were conferred upon Professor Calmette, Lille University; Professor Perroncito, Turin University; Professor Salomonsen, Copenhagen University, and Captain R. F. Scott, R.N.

PROFESSOR K. MÖBIUS has retired from the directorship of the Berlin Museum of Natural History. The position has been offered to Professor H. H. Schauinsland, director of the museum at Bremen.

DR. FRIEDRICH PAULSEN, professor of philosophy at Berlin and known also for his works on education, will lecture at Harvard University during the first half of next year in accordance with the plan for an exchange of professors. As already noted, Professor Francis G. Peabody will lecture at Berlin.

VICE-ADMIRAL HUMAN has been elected president of the French Society of Geography.

DR. GEORGE BRUCE HALSTED has been made foreign associate and honorary professor of mathematics in the popular university of Tempio, Italy, and a fellow of the Royal Astronomical Society.

THE Relation of Graduate Study to General Culture' was the subject of a lecture, given on February 3, at the University of Chicago, by Professor Josiah Royce, of Harvard University.

A CONFERENCE on school hygiene, arranged by the Royal Sanitary Institute, was held in the University of London, under the presidency of Sir Arthur W. Rücker, on February 7-10.

DR. MURGOCI, professor of geology at Bucharest, is carrying on research work in California.

DR. BURTON E. LIVINGSTON, of the department of botany of the University of Chicago, has been appointed to the staff of the Bureau of Soils in the United States Department of Agriculture, and will begin his new work at the close of the winter quarter.

DR. D. T. MACDOUGAL has started on an expedition to lower Colorado and the upper portion of California to collect botanical specimens for the New York Botanical Garden and to study the flora of that region.

MISS VERA K. CHARLES, scientific assistant in the Bureau of Plant Industry, U. S. Department of Agriculture, has recently returned from the Isle of Pines, where she was collecting in the interest of the herbarium connected with the office of vegetable pathological and physiological investigations.

THE SAMUEL D. GROSS prize of the Philadelphia Academy of Surgery, for the year 1905, amounting to $1,200, has been awarded to Dr. James Homer Wright, of Boston, Mass., for his essay, 'The Biology of the Microorganism of Actinomycosis.'

THE Wilde medal of the Manchester Literary and Philosophical Society has been awarded to Professor C. Lapworth, F.R.S., professor of geology at Birmingham.

THE St. Petersburg Academy of Sciences. has awarded the Lomonosoff prize of $500 to Professor N. A. Menschutkin for his researches in theoretical chemistry, and the Ivanoff prize to Professor P. N. Lebedeff, of Moscow, for his experimental researches on the pressure of light.

AT a meeting of the trustees of the Percy Sladen fund, held recently at the rooms of the Linnean Society, London, grants were made to Mr. W. R. Ogilvie Grant towards the expenses of a collector for the British Museum in Central Africa; to Miss Alice L. Embleton to enable her to continue her investigations in insect cytology; and to Mr. J. Stanley Gardiner towards the expenses of an expedition to the Indian Ocean.