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men in the service for temporary duty for the education of these men and give them one month or two months of lectures, and without disorganization we could give our surgeons the absolutely necessary instruction and all around service we have been trying to develop in a more or less haphazard way.

THE INTERALLIED SCIENTIFIC FOOD COM

MISSION

AT an interallied conference, which was held last November in Paris, it was agreed, according to the British Medical Journal, that a Scientific Food Committee should be formed containing two delegates from each of the following countries: Great Britain, France, Italy and America. This committee was to have its permanent seat in Paris, and was to meet periodically in order to examine, from the scientific point of view, the interallied program for food supplies. It was empowered to make any propositions to the allied governments which it thought fit. The delegates appointed from the various countries were: Great Britain: Professor E. H. Starling and Professor T. B. Wood; France: Professor Ch. Richet and Professor E. Gley; Italy: Professor Bottazzi and Professor Pagliani; America: Professor R. H. Chittenden and Professor Graham Lusk. The first meeting of this Commission was held in Paris on March 25, and the following days. At their first sitting the commission was received by M. Victor Boret, minister of agriculture and food. In his opening address M. Boret pointed out that the object of the conference was to study the best means of utilizing the very small food resources at the disposal of the allies so as to effect an equitable distribution of the available food supplies among the allies, having proper regard to the facts of physiology and political economy. He sketched shortly the work of the commission, and his suggestions were embodied later in a series of questions which were adopted by the commission as the problems that would immediately occupy its attention. The commission agreed to establish a permanent central secretariat in Paris, M. Alquier being appointed secretary. In addition to the central secretariat it was agreed that a secretary to the commission should be

appointed in each of the allied countries. At its meetings, which lasted till March 29, the commission considered many important questions relating to the minimum food requirements of man, and to the production and distribution of food supplies. The commission will reassemble at intervals, in Paris or in some other of the allied capitals. Professor Gley has stated that it will probably meet next at Rome towards the end of this month.

SCIENTIFIC NOTES AND NEWS PROFESSOR DUGALD C. JACKSON, of the department of electrical engineering of the Massachusetts Institute of Technology, has been called to France as a major in the Engineer Reserve Corps.

PROFESSOR PHILIP B. WOODWORTH, dean of electrical engineering of Lewis Institute, Chicago, has entered the government service as a major in the aviation section of the Signal Corps.

DR. H. E. WELLS, professor of chemistry at Washington and Jefferson College, has been commissioned captain in the Chemical Service Section of the National Army.

DR. GEORGE WINCHESTER, professor of physics of Washington and Jefferson College, has been commissioned first lieutenant in the aviation section of the Signal Corps, and is now in France.

MR. LAWRENCE ERICKSON has resigned an instructorship in botany in the New York State College of Agriculture and has enlisted in the Coast Artillery.

DR. LEWIS KNUDSON, professor of botany in the New York State College of Agriculture, has obtained a leave of absence and is now in Y. M. C. A. work in France.

CALVIN H. CROUCH, who for seventeen years has been at the head of the mechanical engineering in the University of North Dakota, has accepted a position at Mt. Holyoke, Mass., with the Deane Plant of the Worthington Pump and Machinery Corporation, which is making war material for the government.

J. ANSEL BROOKS, professor of mechanics and mechanical drawing at Brown University, has

entered the engineering section of the aviation service, and is stationed at Lake Charles, La. MR. WATSON BAIN, professor of applied chemistry at the University of Toronto, has been granted leave of absence for the duration of the war. He is going to Washington, D. C., where he will be on the staff of the Canadian mission.

E. A. RICHMOND, instructor in physiology at Simmons College, has joined the Signal Corps. At present he is doing research work in physiology at the Medical Research Laboratory in Mineola, N. Y.

DR. WALTER M. MITCHELL, formerly of the astronomical department of the University of Michigan, and recently mechanical engineer with the Midvale Steel Co., Philadelphia, has received an appointment in the Signal Corps, U. S. A. Dr. Mitchell is stationed at Rochester, N. Y., and is placed in charge of the inspection of equipment for the Signal Corps in that district.

DR. A. D. BROKAW, assistant professor of mineralogy and chemical geology at the University of Chicago, has been called to Washington to take charge of the oil production east of the Rocky Mountains.

DR. E. B. SPEAR, professor of chemistry of the Massachusetts Institute of Technology, has been appointed consulting chemist to the Bureau of Mines in connection with the gas warfare work.

P. W. MASON, assistant professor of entomology in Purdue University, has resigned to accept a position in the Bureau of Entomology, U. S. Department of Agriculture, Washington, D. C.

R. V. MITCHELL, professor of poultry husbandry at Delaware College, has been granted leave of absence to do work with the U. S. Food Research Laboratory along the line of poultry and egg handling.

DR. C. L. REESE, of E. I. du Pont de Nemours & Co., has been named chairman of the committee on dyestuffs and intermediates of the Chemical Alliance.

DR. CHARLES KEYES, Consulting mining engineer and geologist of Des Moines, has been

chosen by the Democrats of Iowa for candidate for United States senator, to succeed Senator W. S. Kenyon, whose term expires shortly.

DR. ROYAL S. COPELAND has been appointed by Mayor Hylan to be health commissioner of New York City.

DR. H. E. DUBIN has resigned as chemist to the Montefiore Home and Hospital to accept the appointment of research chemist with the Herman A. Metz Laboratories, Inc., New York City.

AFTER thirty-eight years' service, Mr. Richard Hall has retired from the staff of the geological department of the British Museum.

CAPTAIN ROALD AMUNDSEN proposes to leave Norway this summer in his new Arctic vessel, the Maud, which has been specially built for this attempt to reach the North Pole. The vessel is to be provisioned and fitted out for a seven years' stay in the ice, but Captain Amundsen hopes to be back within four years.

PROFESSOR J. H. JEANS, the physicist, has been elected a member of the Athenæum Club for distinction in science.

PHILIP E. EDELMAN, of St. Paul, Minn., has been awarded the Research Corporation fellowship in applied science on competition by a jury consisting of the president of the National Academy of Sciences, the secretary of the Smithsonian Institution, the president of the American Chemical Society, the president of the Research Corporation and the chairman of the Engineering Foundation, upon evidence of scientific attainments, inventions and special fitness for advanced work. Mr. Edelman is an electrical engineering graduate of the University of Minnesota and has served as electrical engineer for radio-communication interests. He is the author of "Experimental Wireless Stations" and other popular technical books, and has since February, 1917, devoted his time principally to research work for the govern

ment.

DR. RAYMOND PEARL, of the United States Food Administration, lectured on May 9 at the Washington Academy of Sciences, the subject of the lecture being "Biology and War."

DR. F. G. Novy, professor of bacteriology and director of the hygienic laboratory, University of Michigan, addressed the Cincinnati Research Society, in the surgical amphitheatre of the Cincinnati General Hospital, on May 1, on "Blood Changes and Anaphylaxis," and on May 2, on "Blood Parasites."

Ar the meeting of the Chemical Society at London, on April 18, the first of the Hugo Müller lectures was delivered by Sir Henry Miers, whose subject was "The Old and the New Mineralogy."

GIRTON COLLEGE, Cambridge, plans to found a fellowship for the encouragement of research in natural science, and especially in botany, as a memorial of Miss Ethel Sargant.

A BRONZE bust of the late Dr. Daniel Giraud Elliot, mammalogist and ornithologist, is installed on the second floor of the American Museum, in the hall devoted to birds of the world. The bust, which is the work of Mr. Chester Beach, is the gift of Miss Margaret Henderson Elliot, daughter of Dr. Elliot.

DR. EPHRAIM FLETCHER INGALS, professor of diseases of the chest, throat and nose in the Rush Medical College, Chicago, and active in medical research and organization, died on April 30, aged seventy years.

DR. ARMAND THEVENIN, of the Sorbonne, known for his work in paleontology, died on March 7, aged forty-eight years. He had been experimenting with poisonous gases and in the course of his work contracted the illness which proved fatal.

MR. W. HAGUE HARRINGTON, one of the best known of the older Canadian entomologists, died on March 13 at Ottawa, Canada, at the age of sixty-six years. Mr. Harrington was born in Novia Scotia, and entered the federal civil service at Ottawa in November, 1870, eventually reaching the rank of superintendent of the Savings Bank Branch. He was one of the founders of the Ottawa Field Naturalists' Club, and at one time was president of the Entomological Society of Ontario. In 1894, he was elected a fellow of the Royal Society of Canada. For many years his main interest in life was entomology, and he brought together

a large collection of Canadian Coleoptera and Hymenoptera. He was a systematist of recognized standing, and was probably the highest authority on Hymenoptera in the Dominion of Canada. He was a striking example of that class of men who have done pioneer work in natural history in Canada and the United States, while pursuing this work as a hobby rather than as a vocation.

UNIVERSITY AND EDUCATIONAL
NEWS

THE Kentucky legislature in the session ending on March 15 made a notable change in the laws providing for the support of institutions of higher education. In view of the material increase in the state's property assessment by the tax commission the legislature passed the reapportionment tax bill and gave the university a rate of 134 cents on each hundred dollars of the assessment. This provision will give the university an increase of $200,000 annually over the income it has had in previous years. Plans are now under way for a material increase in the teaching staff and the undertaking of extensive repairs in the plant of the university. Olmstead Brothers, of Brookline, Mass., have been employed to work out plans for campus improvements. Due to war conditions, no new buildings will be constructed at present. President McVey, formerly of the University of North Dakota, began his service with the University of Kentucky last September.

ANNOUNCEMENT is made of the completion of the diamond jubilee fund of $800,000 for the Ohio Wesleyan University.

A NEW chemistry building is to be erected on the campus of the University of North Dakota. The ground has already been broken and contracts for the construction of the building have been let by the State Board of Regents, at a cost of $62,483.

AT a recent meeting of the council of the University College of Wales, Aberystwyth, it was reported that an anonymous donor was prepared to transfer the sum of £10,500 to the college for the purpose of endowing a chair in geography and anthropology. Herbert John

Fleure, who was appointed professor of zoology at the college ten years ago, will now devote all his energies to the department of geography.

DR. R. H. JESSE, JR., head of the department of chemistry at the Montana State University at Missoula, has been appointed dean of men for the institution.

DISCUSSION AND CORRESPONDENCE ASTIGMATISM AND COMA

PERHAPS the clearest statement of the prevailing theoretical distinction between the five spherical aberrations is that given in the last edition of the Encyclopedia Britannica by Dr. Eppenstein of the Zeiss factory.

The differentiation there made between astigmatism and coma is not, however, in strict conformity with the facts. The term astigmatism" as applied to lenses has always referred to the increasing lack of sharpness in the image towards the edge of the field in an uncorrected or poorly corrected lens system and coma" to the peculiar radial flare sometimes very evident in the outer portions of the field.

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The explanation given in the article just referred to is that astigmatism is the aberration due to obliquity and is therefore fully shown by very narrow bundles of rays, while coma can not be shown at all except with a wide bundle.

This explanation is the result of reasoning from the theory of astigmatism devised by Sturm, who assumed a behavior of oblique rays completely at variance with the facts. By the use of a method developed by the writer it is possible to calculate with strict. accuracy the path and focal point of any ray through a lens surface from any point of the field by the use of which it became at once evident that the two foci calculated by Sturm's method locating the position of the two astigmatic surfaces are pure fictions, though this calculation is nevertheless a rough numerical approximation of this aberration. The detail of the new method of calculation will be presented elsewhere.

As a matter of fact only distortion and curvature are independent of the bundle width,

and both coma and astigmatism are increased with increase in the width of the ray bundles, and it is not true, as stated in this article, that coma alone is the result of the width of the ray bundle. This can be very easily proven without recourse to mathematical calculations by the use of a poorly corrected photographic lens, examining the images on the ground glass or making photographs of a grating, using a wide and a narrow stop.

The best known test for astigmatism is the fact that where this aberration is uncorrected one of two crossing lines may be very vague, while the other is sharp and distinct. This is best seen with the wide stop. The effect is usually explained according to the Sturm theory by saying that only one of these lines can be in focus at a time and that either may be brought into focus. If one will shift the ground glass he can easily prove that only radial lines can be sharply focused by an uncorrected lens, and that towards the edge of the field lines at right angles to these radial lines can not be brought into focus at all and are in fact most nearly in focus on the same plane as the radial lines.

When the grating is rotated 90° the lines that were vague may become sharp but only when a line is approximately radial is the effect of astigmatism nullified.

Both astigmatism and coma consist in a longitudinal spreading out of the image produced by the zones of the lens. The radial lines remain sharp because the shifting is radial and the shifted images of a radial line are superimposed, the line remaining sharp because its width is not increased to an appreciable extent.

Instead therefore of making the distinction expressed by Dr. Eppenstein that the features of lateral aberration due to obliquity constitute astigmatism, and that those dependent on difference of zones produce coma, the writer would suggest that the former be defined as the difference of focus produced by the median region of the lens and that of the most distant marginal point while the latter represents the focal difference of the nearest marginal point of the lens.

The reasons for these new suggestions are: (1) That the sharpest focus is normally produced by the central portion of the lens and lateral aberrations depend on differences of focus that may result from the passage of light rays through a marginal region of the lens; (2) that the best measure of lateral aberrations are the extreme deviations, and these are those of a point at the edge of the object field through the nearest and through the most distant marginal point of the lens; (3) that the greatest difference of focus of a lateral object between the central image and that produced through an edge point is the one produced by the most distant point on the lens surface and therefore this may most appropriately be designated astigmatism; (4) that the focus through the nearest marginal point of the lens may lie on either side of the median focus and if on the same side as that of the distant marginal point there is produced the characteristic optical effect called coma, and finally (5) that these two measurements are strictly comparable with the measurement always made to determine the longitudinal aberration of the axial rays and are therefore the only consistent methods of determining the two lateral aberrations.

C. W. WOODWORTH

UNIVERSITY OF CALIFORNIA

OBSERVATIONS ON THE AURORAL CONVERGENT, APRIL 5, 1918

AN auroral display of more than usual interest occurred on Friday evening, April 5, 1918, and was observed by the writer from a point about one and a half miles southeast of the Dominion Observatory, Ottawa.

At about 10.30 P.M. the rays seemed to be converging at a more or less well-defined point approximately half way between Saturn and the "Big Dipper." For all that the writer knew the position or path of the point of auroral convergence and its height above the earth's surface had been subject to such frequent observation that any measurements he might make on this particular evening would be superfluous, but they seemed to him more worthy of record for a scientific magazine than

the random descriptions of color, play of light and duration which have recently appeared and he decided to see whether or not the position of the point of convergence could be determined with any degree of accuracy.

Exact Western Union time was obtained from "central," but the rough nature of the observations makes the times recorded below approximate only, say within one minute, the fact that they are recorded as 11.20 and 11.40 being due not to rough estimation but to choice. The writer used a clothes reel with taut wires, revolving it so that one of the wires intersected both Saturn and the point of convergence. Three small markers (inch wide) were hung on the wire and moved about until they covered Saturn, the point of convergence (convergent), and another known point or star, all in line.

The following observations were made:

10.55 P.M. Saturn, convergent, and Mizar in line. Saturn to convergent: convergent to Mizar :: 112: 101.

11.20 P.M. Saturn, convergent, and star at end of handle of "Big Dipper" in line. Saturn to convergent: convergent to star

:: 113:8ğ

11.40 P.M. Saturn, convergent, and point in sky on line from Mizar through end of "Big Dipper" handle and the barest fraction (say one sixth) farther from the end of the handle than that is from Mizar, all in line. Saturn to convergent: convergent to point :: 131:7

11.55 P.M. Saturn, convergent, and Gamma of Bootes in line.

Saturn to convergent: convergent to Gamma

::15:71

For the last observation (11.55 P.M.) the rays of light had become faint enough to make the exact position of the convergent somewhat doubtful and measurements were discontinued. In fact the latter observation was taken at 11.55 instead of at midnight, which would have preserved the 20-minute interval, because of a fear that the position of the convergent would become too indistinct for observation.

There was a perceptible tendency for the

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