bear. Four kinds of ground sloths have been obtained in Cuba and one in Porto Rico; all are related to the large extinct North American ground sloth Megalonyx. There are also several kinds of rodents, all of them distantly related to South American groups, chinchillas, spiny rats and perhaps agoutis, and a very remarkable little insectivore which is in a family by itself, and is found both in Porto Rico and Cuba. A giant tortoise, very thin-shelled like the tortoises of other oceanic islands but in some respects very peculiar, a terrapin which still lives on the islands and is closely related to species of the southeastern United States, and a crocodile also still living and near to a Central American species, are the principal fossil reptiles. Although the collections are large, no trace of any kinds of hoofed animals or carnivora have been found, nor any other kinds of rodents save the above South American groups, or of edentates except the one family of ground sloths. The characters of the fauna are believed to prove that the islands have been isolated for a long time, at least since the early Pliocene, and have never had any direct connection with North America; and to indicate that they have probably never had any land connection with South or Central America. There is little question that during the Pliocene or Pleistocene the islands were elevated to or near the borders of their submarine shelves, enlarging and connecting them to some extent, and there is some evidence, but not conclusive, for union of the greater Antilles and as far east as the Anguilla bank.

Characters and restoration of the Sauropod genus Camarasaurus Cope, from the type-material in the Cope collection of the American Museum of Natural History: HENRY FAIRFIELD OSBORN, research professor of zoology, Columbia University, and CHARLES C. MOOK.

Energy conception of the cause of evolution: HENRY FAIRFIELD OSBORN.

The parasitic Aculeata, a study in evolution (illustrated): WILLIAM M. WHEELER, professor of economic entomology, Bussey Institution, Harvard University.

Two recent entomological problems—the pink bollworm and the European corn borer: L. O. HOWARD, chief of Bureau of Entomology, U. S. Dept. of Agriculture, Washington.

Hydration and growth: D. T. MACDOUGAL, director of the department of botanical research, Carnegie Institution of Washington, Tucson, Arizona.

Hydration of agar and agar-protein in propionic acid and its amino-compounds: D. T. MACDOUGAL, director of the Desert Laboratory, Tucson, Arizona, and H. A. SPOEHR. Sterility and self-and-cross-incompatability in shepherd's purse (illustrated): GEORGE H. SHULL, professor of botany and genetics, Princeton University.

Sexual reproduction is a complex succession of processes, all of which must be coordinated with a considerable degree of perfection in order to be successful. The chain of events leading from the spore mother-cells (oogonia, spermatogonia) through successful fertilization to fully developed viable seeds, may be broken at any one of a number of different points, and may be affected by many agents, both environmental and hereditary. No one should expect, therefore, to be able to bring all cases of sterility under a common viewpoint. In the common shepherd's purse (Bursa Bursa-pastoris) there exists a great number of biotypes, each of which has its own characteristics with respect to sterility and fertility, as well as other features, both morphological and physiological. In most of the common forms growing in Europe and eastern North America the lower flowers of the main axis are nearly always entirely sterile. A species common throughout the Pacific coast region of North and South America, and extending at least as far eastward as Tucson, Arizona, has, on the other hand, no sterile flowers at the base of the central raceme. A form similar to the Pacific coast form has also been found in Holland. A cross between the Tucson plants and those from eastern America has given rise to partially sterile hybrids which are characterized by rhythmic succession of sterile and fertile flowers, and there is some evidence that this rhythmic arrangement is under the control of two genetic factors, so that the F2 from such a cross consists of about one like either parent to fourteen which display again a rhythmic succession of sterile and fertile flowers.

2

The basis of sex inheritance in Sphærocarpos (illustrated): CHARLES E. ALLEN, professor of botany, University of Wisconsin. (Introduced by Professor Bradley M. Davis.) Hydrogen-ion concentration of nutrient solutions in relation to the growth of seed plants: BENJAMIN M. DUGGAR, research professor of plant physiology, Missouri Botanical Garden, St. Louis. (Introduced by Professor Bradley M. Davis.) The relation of the diet to pellagra (illustrated):

E. V. MCCOLLUM, professor of bio-chemistry, Johns Hopkins University. (Introduced by Dr. Henry H. Donaldson.)

Friday, April 25, 2 o'clock George Ellery Hale, Ph.D., Sc.D., LL.D., vicepresident, in the chair

The eclipse expedition from the Lick Observatory: some solar eclipse problems (illustrated): W. W. CAMPBELL, director of the Lick Observatory, Mount Hamilton, Calif.

The expedition of the Mount Wilson Observatory to the solar eclipse of June 8, 1918 (illustrated): J. A. ANDERSON, Mount Wilson Solar Observatory, Pasadena, Calif. (Introduced by Professor John A. Miller.)

A description of the equipment used at Green River was given; the compact arrangement of the different units being the chief feature. Owing to clouds, the results were not what was hoped for. Good photographs of the corona were secured; the wave-length of the green coronal line was quite accurately determined; and certain data of value for future eclipse work were obtained. The

Lowell Observatory eclipse observations, June 8, 1918: prominences and coronal arches (illustrated): CARL O. LAMPLAND, Lowell Observatory, Flagstaff, Arizona. (Introduced by Professor Eric Doolittle.)

The author deals with some of the more important results obtained by the expedition sent sent out by his institution, but especial attention is given to the prominences and the detail of the inner corona. Several conspicuous prominences were shown in the photographs and these are generally surrounded by complex coronal structure. These coronal arches or "hoods" are probably among the most conspicuous and remarkable photographed up to the present time. In the present observations there appears to be no doubt as to the intimate relation between the prominences and the surrounding coronal structure. From a comparison of the observations of earlier eclipses made at different epochs of solar activity it seems probable that complex coronal detail and disturbed regions of the corona around and in the neighborhood of the prominences are more pronounced near sun-spot maxima; that such detail is much less conspicuous and occurs more rarely at or near the minima of sun-spot activity.

The flash spectrum (illustrated): SAMUEL ALFRED MITCHELL, director, McCormick Observatory, University of Virginia. (Introduced by Professor John A. Miller.)

Electric photometry of the 1918 eclipse (illustrated): JACOB KUNZ and JOEL STEBBINS, University of Illinois, Urbana, Ill. (Introduced by Professor John A. Miller.)

The Sproul Observatory eclipse expedition: The form of the coronal streamers (illustrated): JOHN A. MILLER, director of the Sproul Observatory, Swarthmore College, Pa.

Results of observations of the eclipse by the expedition from the Yerkes Observatory: EDWIN B. FROST, professor of astrophysics and director of Yerkes Observatory, University of Chicago.

Self-luminous night haze (illustrated): E. E. BARNARD, professor of practical astronomy, University of Chicago.

The author dealt with a little-known feature of the night skies. It is a faintly luminous haze that is sometimes visible on otherwise clear nights when the moon is absent. It does not seem to be connected with any known auroral phenomenon. It seems not to be some form of cirrus or cirrostratus cloud that for some reason, on rare occasions, is more or less faintly self luminous at night. The source of its light is unknown. When best seen it is quite noticeable as a streaky luminous haze; sometimes it appears in broad sheets. It drifts easterly over the stars and remains visible with a faint steady light for a considerable length of time. Sometimes it seems to be absent for several years. At other times there is a great deal of it. It is seen in all parts of the sky, differing thus from the ordinary auroral phenomena, which are mostly confined to the northern part of the sky.

Photometric measurements of stars: JOEL STEBBINS, professor of astronomy, University of Illinois. (Introduced by Professor Henry Norris Russell.)

Star clusters and their contribution to knowledge of the universe: HARLOW SHAPLEY, Mt. Wilson Solar Observatory, Pasadena, Calif. (Introduced by Professor George E. Hale.)

Tatar material in old Russian: J. DYNELEY PRINCE, professor of Slavonic languages, Columbia University.

Friday Evening, April 25

Reception from eight to eleven o'clock in the hall of the Historical Society of Pennsylvania,

EXECUTIVE SESSION-9.30 O'CLOCK Special business-Action upon the proposed amendments to the laws.

Stated business-Candidates for membership balloted for, with the result that the following new members were declared elected: Robert Grant Aitken, Sc.D., Mount Hamilton, Calif.; Joseph Charles Arthur, Sc.D., Lafayette, Ind.; Edward W. Berry, Baltimore; James Henry Breasted, A.M., Ph.D., Chicago; Ulric Dahlgren, M.S., Princeton; William Curtis Farabee, A.M., Ph.D., Philadelphia; John Huston Finley, LL.D., Albany, N. Y.; Stephen Alfred Forbes, Ph.D., LL.D., Urbana, Ill.; Chevalier Jackson, M.D., Philadelphia; Dayton C. Miller, A.M., D.Sc., Cleveland; George D. Rosengarten, Ph.D., Philadelphia; Albert Sauveur, S.B., Cambridge, Mass.; William Albert Setchell, A.M., Ph.D., Berkeley, Calif.; Julius O. Stieglitz, Ph.D., D.Sc., Chicago; Ambrose Swasey, Sc.D., D.E., Cleveland.

10 O'CLOCK

Hampton L. Carson, M.A., LL.D., vice-president, in the chair

Artificial formations resembling lunar craters:
CAPTAIN HERBERT E. IVES, of Philadelphia.
The meteorological service of the Signal Corps in
the war: ROBERT A. MILLIKAN, professor of
physics, University of Chicago.
Detection of submarines (illustrated): HARVEY
CORNELIUS HAYES, Naval Experiment Station,
New London. (Introduced by Professor John
A. Miller.)

This paper discussed various possible methods. The most effective one resulted from the development of a system of multiple sound sensitive receivers mounted in such a way as to transmit to both ears of the observer a cumulative or summational impulse which becomes a maximum when the instrument is properly directed, thus showing the direction of the submarine. It is clear that such an instrument would be valuable in peace times also in indicating the presence and direction of vessels in a fog.

Errors induced in bullets by defects in their manufacture: ERNEST W. BROWN, professor of mathematics, Yale University.

Sound and flash ranging: AUGUSTUS TROWBRIDGE, professor of physics, Princeton University, and late Lieutenant Colonel Engineers, of General Pershing's staff and in technical charge of the ranging service in the A. E. F.

The work of the Ballistic Institute of Clark University: A. G. WEBSTER, professor of physics, Clark University, Worcester, Mass. Alternating-current planevector potentiometer measurements at telephonic frequencies (illustrated): A. E. KENNELLY, director, Research Division, Electrical Engineering Department, Massachusetts Institute of Technology, Cambridge, and EDY VELANDER.

The genesis of petroleum as shown by its nitrogen constituents: CHARLES F. MABERY, emeritus professor of chemistry, Case School of Applied Science, Cleveland.

Since so far as known complex nitrogen bases are produced in nature only through the agency of vegetable or animal life the universal presence of these bases in petroleum seems to be convincing evidence as to its origin. In most of the denser varieties these bases have been detected, in California and Russian petroleum in considerable amounts. In the present paper results are presented which show that the same or similar bases are generally present in the lighter varieties of the eastern fields-Pennsylvania, West Virginia and the Berea Grit of southern Ohio. I procured authentic specimens from these fields and find that they all contain from one part in 10,000 to one part in 20,000. A special method of analysis had to be devised to determine such minute proportions of nitrogen, a combination of the Dumas method for nitrogen and the oxygen method for carbon and hydrogen. Briefly described, the combustion was made in a glass tube one half filled with copper oxide, and in the vacant space the oil was placed in a boat with an oxidized copper roll behind and next behind a large boat containing potassium chlorate. In a second furnace was placed a steel tube filled with copper oxide, and heated to full redness to oxidize completely the hydrocarbons. Tight joins were made with castor oil seals and with a special form of rubber tube also luted with castor oil. Nitrogen was sufficiently removed by CO2 from a rear generator containing several pounds sodium bicarbonate and repeated evacuations with a power pump extending through several days. The paper gives the results of analysis

in a table and in another table the history of the samples.

Graphic representations of functions of the nth degree: FRANCIS E. NIPHER, professor emeritus of physics, Washington University, St. Louis. Glimpses of the near east during the war: A. V. W. JACKSON, professor of Indo-Iranian languages, Columbia University.

The empire of Amurru: A. T. CLAY, professor of Assyriology and Babylonian literature, Yale University.

The science of stealing (steyacastra) in ancient India: MAURICE BLOOMFIELD, professor of Sanskrit, Johns Hopkins University.

The crib of Christ: PAUL HAUPT, professor of Semitic languages, Johns Hopkins University. The word translated "manger" in Luke II. 7, denotes one of the arched and open recesses in front of the travelers' chambers along the interior court of a caravansary. Shakespeare uses "'crib" in the sense of "small chamber." The inn in which Jesus is said to have been born may be the hostelry mentioned in Jerem. XII. 17 where the Revised Version gives in the margin: the lodgingplace of Chimham. The caravansary may have been founded by Chimham, the son of Barzillai, who followed David to Jerusalem (II. Sam. XIX. 38). The name Bethlehem is derived from this ancient inn near the town, on the road from Jerusalem to Hebron. Bethlehem does not mean House of Bread, but House of Bait, i. e., halt for refreshment.

The atonement idea among the ancient Semites: EDWARD CHIERA, instructor in Assyriology, University of Pennsylvania. (Introduced by Professor Morris Jastrow, Jr.)

Saturday, April 26, 2 o'clock Arthur A. Noyes, Sc.D., LL.D., vice-president, in

the chair

Symposium on Chemical Warfare-Historical introduction: COLONEL MARSTON T. BOGERT, Chemical Warfare Service, U. S. A.

The speaker gave a brief review of the history of chemical warfare both before and during the war, pointing out the high spots in the field and including also an outline of the organization of the Chemical Warfare Service of the United States Army and its activities.

Chemical warfare and research: COLONEL GEORGE A. BURRELL, Chemical Warfare Service, U. S. A. (Introduced by Colonel Bogert.)

Chemical warfare and manufacturing development: COLONEL FRANK M. DORSEY, Chemical Warfare Service, U. S. A. (Introduced by Mr. A. A.

Blair.)

Production of chemical warfare munitions (illus. trated): COLONEL WILLIAM H. WALKER, Chemical Warfare Service, U. S. A. (Introduced by Professor H. F. Keller.)

Production of chemical warfare munitions (illustrated): COLONEL BRADLEY DEWEY, Chemical Warfare Service, U. S. A. (Introduced by Dr. Philip B. Hawk.)

This paper discussed the following points: (1) The problem of making over 5,600,000 gas masks in eight months; 5,000,000 of these going overseas together with 2,800,000 extra canisters. (2) The history of starting a government-owned factory at Long Island City, which on the day of the armistice covered à million square feet of floor space and had 12,500 employees. (3) The problem of manufacturing the chemicals for gas masks, with mention of the fact that 50 tons a day were necessary and with emphasis of the part played by the peach pit campaign in furnishing some of the 400 tons a day of coconut shells and peach pits necessary to produce the gas mask charcoal. (4) Mention of the manufacture of one half million horse masks and miscellaneous gas defense protective apparatus, other than horse masks. (5) A description with lantern slides showing some of the work done by the Field Testing Section, digging trenches and fighting miniature battles in gas in order to work out the characteristics of gas masks.

The usual banquet on Saturday evening was given at the Bellevue Stratford with about seventyfive members and guests present. Toasts were responded to by Honorable George Gray, Professor E. G. Conklin, Professor J. W. Bright and Dr. J. W. Holland. ARTHUR W. GOODSPEED