ten weeks. It was found difficult to carry definite specific larvæ under observation in Petri dishes through the entire period, but the time was established by noting the appearance of new groups of moths in the larger stock of fur. Just what there was in the Petri-dish method of culture to hinder the larval development could not be determined. Some larvæ grew to large size, approximating maturity, others died in a few weeks, but none were certainly carried from the egg to the cocoon. Ten weeks appeared to be the shortest period in which larval growth was completed, but this is necessarily partly an estimate.

The cocoon stage lasted at the shortest two weeks. This was definitely established by observing the time at which larvæ ceased feeding, and closed their cases, and then putting such cases away for observation.

It is probable that all stages of the life history may under some circumstances be more or less indefinitely lengthened. Certainly the larval stage may. Its conclusion probably depends entirely on the obtaining of a sufficient amount of food, and may probably last several months, as over winter for example. Winter stops the activities of this moth only when the temperature of the surroundings is too much lowered. In the present investigation moths were observed emerging from cocoons and larvæ were seen feeding during all months of the year. Breeding experiments were not attempted during the winter but there seems no reason to suppose they would not have been successful and that egg-laying would also have occurred.

Remedies for Moths.-A summary of results along this line may be interesting.

Remedies intended for the flying-moth stage are worse than useless. So-called repellants such as tobacco, cedar, did not repel or harm the moth in any stage. The imago stage is the most delicate of all, but it could be placed in a small closed tumbler with burning tobacco with no apparent injury. Cloth soaked in odoriferous substances for the purpose of repelling them was made the recipient of eggs as readily as untreated cloth. As already noted, the moth laid eggs as readily on cotton and silk as

on wool although neither of these was used as food by the larvæ.

Any method of attack must be directed toward the larval stage to be effective. Camphor and napthalene in closed places kill all stages. The egg and larvæ turn from whitish to a yellowish brown in color; the larvæ cease activity almost immediately. No gaseous poisons were tried but undoubtedly the common ones would be effective. Kerosene and gasoline fumes were not effective.

The main method of attack in this case was directed toward poisoning the larvæ through their food. The problem was to find some poison which could be placed on cloth and serve to kill larvæ feeding on it before they could do material damage. At the same time it must not be harmful to human beings, or if harmful in posse, must be insoluble. If baby wants to chew mother's dress or its woolen blanket, it must be able to do so with impunity. After about four years of nearly continuous investigation, during which several chemists were cooperating, the problem was finally dropped. Numerous compounds were used in tests but the larvæ proved singularly immune. Larvæ placed in Petri dishes with a piece of cloth soaked in corrosive sublimate as well as other common poisons, ate of the cloth as shown by the color of their alimentary canal and the fæces, but lived on for weeks apparently uninjured. Some few substances were found which did appear to have some result but not enough to justify adopting them as the basis of a mothproofing process.

The problem still seems to be possible, but the solution is not apparent. After the substance is found, there still remains the overcoming of the objections of the tailors and clothing manufacturers, some of whom consider clothes moths among their best friends. RALPH C. BENEDICT

BROOKLYN

A CHROMOSOME DIFFERENCE CORRELATED WITH SEX DIFFERENCES IN

SPHÆROCARPOS

THE chromosome group found in the cells of the female gametophyte of Sphærocarpos Donnellii contains one large element which

considerably exceeds both in length and in thickness any of the older chromosomes. The chromosome group of the male gametophyte contains no element similarly distinguished by its size; on the other hand, the male possesses a very small chromosome which seems not to correspond in size to any element in the female.

The other chromosomes in the cells of either sex have the form of slender rods; there are noticeable differences in length between those of each group. The bending and not infrequent overlapping of the ends of the chromosomes place difficulties in the way of an exact determination of their number; but, subject to modification by further study, it may be said with reasonable assurance that the chromosome number for each sex is eight. As to seven of the eight, the chromosomes of the male seem to resemble those of the female; but the eighth chromosome of the female is probably corresponding to it in the male is the the large one already referred to, and the one very small chromosome.

Of the two spindles formed in each spore mother cell at the time of the homeotypic division, one shows a large body which is sometimes plainly two-parted; no element appears on the other spindle that approximates in size. this large chromosome. It has been reported that in at least one species of Sphærocarpos two of the spores of each tetrad develop into male plants and the other two into females. Observations which I have made, although as yet in limited number, indicate that the same rule holds for S. Donnellii. The cytological results here reported seem to show that in consequence of the chromosome distribution in the reduction divisions two of the four spores derived from a single mother cell receive each a large chromosome (and seven of smaller size), and these spores develop into female plants; and that each of the other two spores receives a small chromosome instead of the large one, and, on germination, gives rise to a male plant.

The resemblance between this history and that of the chromosomes of certain insects, such as Lygaus and Euschistus, which pos

sess a large X- and a small Y-chromosome, is obvious. It is too early to conclude that the particular chromosomes with respect to which the male and female gametophytes of Sphærocarpos differ are the bearers of definite sexdetermining factors; but it seems not unlikely at least that the greater size and vigor of growth of the female gametophyte are associated with the greater amount of chromatin that its cells contain.

CHARLES E. ALLEN

UNIVERSITY OF WISCONSIN

THE AMERICAN ASTRONOMICAL

SOCIETY

THE twenty-first meeting of the society was held August 29 to 31 at the Dudley Observatory, Albany, N. Y., about ninety members and visitors being present. The arrangements for the meeting were admirably carried out by the host, Professor Benjamin Boss, acting also for the trustees of the Dudley Observatory and the department of meridian astrometry of the Carnegie Institution of Washington. The activities included an excursion to Saratoga Lake and a visit, at the close of the meeting, to Vassar College and its observatory.

Various committee reports and items of business were considered by the society, among others the question of the daylight saving movement, and when an informal expression of opinion was called for, the vote stood

In favor of daylight saving..... 18
Opposed to the plan
Neutral

22

6

༤

46

Another matter in the same connection, which would affect only astronomers, was a proposal coming from England that the astronomical day begin at midnight instead of at noon as at present. A test vote showed that a large majority of the members present were opposed to the change, but after some parliamentary procedure it was agreed to refer the matter to a committee to make a report back to the society.

Officers were elected for the ensuing year as follows:

President-Edward C. Pickering.

First Vice-president—Frank Schlesinger.
Second Vice-president-W. W. Campbell.
Secretary-Philip Fox.

Treasurer-Annie J. Cannon.

Councillors-Ernest W. Brown, Edwin B. Frost, J. S. Plaskett, Joel Stebbins.

The next meeting of the society will be held at the Harvard Observatory about September 1, 1918. Following is the list of papers presented at the meeting, the abstracts of which are published in Popular Astronomy:

Sebastian Albrecht: On the variation in spectral type of the fourth-class variable star Carina.

S. I. Bailey: Note on the variable stars in the globular cluster Messier 15.

L. A. Bauer: A brief statement of the work of the Committee on Navigation and Nautical Instruments of the National Research Council.

R. R. Candor: A mechanical device for interpolation.

Annie J. Cannon: Distribution of light in stellar spectra.

J. B. Cannon: Note on two spectroscopic binaries.

W. A. Conrad: Note on a possible explanation of erratic jumps in clock rates.

R. H. Curtiss: Spectra of Nova Geminorum No. 2 and other stars.

Ralph E. De Lury: A new form of spectrocomparator.

A. E. Douglass: The Steward Observatory of the University of Arizona.

A. E. Douglass: An optical periodograph. Raymond S. Dugan: On the eclipsing variable R Canis Majoris.

W. S. Eichelberger: Eccentricity and longitude of perisaturnium of the orbits of Enceladus, Tethys and Dione.

W. S. Eichelberger: The obliquity of the ecliptic from the Sun observations made at the U. S. Naval Observatory, 1903-1911.

W. S. Eichelberger: The refraction at Washington.

W. S. Eichelberger and F. B. Littell: Day observations minus night observations.

W. S. Eichelberger and H. R. Morgan: Comparison of Washington right ascensions with those of Newcomb, Auwers, Boss, Hedrick and Poulkowa, 1905.

W. S. Eichelberger and H. R. Morgan: Comparison of Washington declinations with those of Newcomb, Auwers and Boss.

George E. Hale: The best service of astronomers in time of war.

W. E. Harper: Notes on some spectroscopic binaries.

C. C. Kiess: On the presence of rare earths in a Canum Venaticorum.

E. S. King: Some recent work in photographic photometry.

Jacob Kunz and Joel Stebbins: Photo-electric observations of new variable stars.

C. O. Lampland: Measures of position of the nucleus of the great nebula in Andromeda. C. O. Lampland: Recent observations of Nova Persei 1901.

C. O. Lampland: Photographic observations of the variable nebulæ N.G.C. 2261 and N.G.C. 6729. F. B. Littell: Variation of latitude at the U. S. Naval Observatory.

W. F. Meggers: Photography of the solar spectrum.

Paul W. Merrill: Photography of the extreme red and infra-red portions of stellar spectra.

Joel H. Metcalf: A comparison of an 8-inch doublet with a 10-inch triple anastigmatic lens. G. H. Peters: The photographic telescope of the U. S. Naval Observatory.

E. C. Pickering: Variation in light of asteroids. W. F. Rigge: The total solar eclipse of June 8, 1918, as visible in the United States.

Luis Rodés: Direct application of Wulf's electrometer for recording the time sent by wireless telegraphy, and its connection with the potassium photo-electric cell to register the duration of totality in a solar eclipse.

H. B. Rumrill: A plea for the small telescope. H. N. Russell: The masses of the stars. H. N. Russell: On the calculation of the orbits of visual binaries.

H. N. Russell: New double star orbits.

F. H. Seares, A. Van Maanen and F. Ellerman: Location of the sun's magnetic axis.

H. T. Stetson: Some recent improvements in thermo-electric apparatus for photographic photometry.

Frank Schlesinger: Determination of stellar parallaxes at the Allegheny Observatory.

V. M. Slipher: Observations of the aurora spectrum.

V. M. Slipher: Spectrographic observations of star clusters.

R. Trümpler: Preliminary results on the constitution of the Pleiades group.

David Todd: Weather prospects along the central line of total eclipse, 1918, June 8.

A. Van Maanen: Discussion of the Mt. Wilson parallaxes.

F. W. Very: On a possible limit to gravitation.

JOEL STEBBINS, Acting Secretary

and organization is destined to be a watchword of the future, whatever the outcome of this war. Organization of our political, economic, educational and general social life will be tried on a scale never before attempted, at least in English-speaking countries. Will the organization attempted be wise or otherwise? Wise social organization is evidently what we need, but it can not be successfully accomplished without scientific knowledge of our social life. Are we, then, as students of the social sciences prepared to give reliable scientific guidance in every field of social activity? Or have we only conflicting opinions to offer? We should face such questions as these candidly. The watchword of the present is "national service." Are we fully prepared to do our "bit" in the work of social reconstruction which our national welfare and security in the future demand? That, for us who are engaged in scientific and educational work along social lines, is a more important question than whether we are ready to do our "bit" in the war itself; for whether this war will prove to be a great victory for humanity and civilization will be evident, not upon the announcement of the terms of peace, but a generation or two thereafter.

While the work of the Social and Economic Section of the American Association may, perhaps, justly be held to be not representative of the best work in the social sciences, yet the general justice of this implied criticism of the social sciences can not be doubted. In spite of the labors of many eminent minds, in the main the social sciences, especially those of a theoretical nature, do remain still to-day in the realm of opinion rather than in the realm of accurate and verified truth. This is shown by the fact that not infrequently even in academic circles they are developed in the service of fads, social, political, metaphysical and methodological. This was once supposed not to be true of the older social sciences, such as economics and politics, but in the light of recent events it would be a very rash man who would affirm that even these older sciences have yet passed from the stage of opinion to that of verified scientific knowledge. It may possibly be said that when the whole world is in a condition of confusion and revolution, it is too much to expect that the social sciences will not also reflect this condition. But science is supposed to be something which, aiming as it does at the discovery of objective, verifiable knowledge, transcends the mere Zeit

The editor of The Scientific Monthly, in commenting on the papers presented before the Section for Social and Economic Science of the American Association for the Advancement of Science in the year 1915, published in the April, 1916, issue of that journal, said:

An obvious difference exists between the eleven sections of the American Association devoted to the natural sciences and the one devoted to the social and economic sciences. The former are in the main concerned with the discovery of truth, the latter in the main with the expression of opin

ion.

a state of confusion, the world can scarcely be expected to look to them to lead it out of its present confusion into a new and better day of peace, harmony and agreement as to the fundamentals of human living. It is true that the disagreements among the more carefully trained scientific social thinkers are much less than what the public suppose; but it is useless to deny that there are disagreements of the most fundamental sort, and that the social sciences suffer, as well as the world, from such disagreements. Of course, the lateness of their development and the complexity of the subject-matter with which they deal ex