The stability of tetryl: C. L. KNOWLES. The following is an outline of the paper: Historical, general methods of preparation; general methods of purification; properties; most common impurities; causes of instability in tetryl; methods of testing stability of tetryl; action of sodium carbonate on tetryl; detection of sodium picrate in tetryl; effect of sodium picrate on stability of tetryl; conclusions; references.

SHALL.

The manufacture of trinitroxylene: JOHN MARThe paper included the following: Discussion of preliminary experiments on the production of TNX; a study of the properties of a mixture of TNX and TNT when cast together; a discussion of the fraction of xylene best adapted to the production of TNX for explosive shell filling. The methd of nitrating; the nitration of pure meta-xylene; the composition of the mixed acid; the study of raw materials with particular reference to the rectification of solvent naphtha and the results obtained from the various ranges of the xylene fraction; the relative suitability of coke oven and water gas tar xylenes.

The preparation of hexanitro-diphenylamine and its use as a booster for shell charges: JOHN MARSHALL. The following is an outline of the paper: Historical; the preparation of dinitrodiphenylamine; preparation of tetranitrodiphenylamine; nitration of tetranitrodiphenylamine to hexanitrodiphenylamine; preparation of hexanitrodiphenylamine by complete nitration of dinitrophenylamine with mixed acid; the neutralization of free acid in hexanitrodiphenylamine; the explosive properties of hexanitrodiphenylamine; sensitiveness of hexanitrodiphenylamine to detonation; sensitiveness to impact; sensitiveness to friction; rifle bullet test; explosive power of hexanitrodiphenylamine; effect as a booster; conclusions.

The composition of sponges: F. P. DUNNINGTON. The common sponge, used in washing, grows in some warmer ocean waters and consists of a network of fiber-like material which is somewhat re

lated in composition to silk fiber. Sponge has long been known to contain the somewhat rare element iodine, and occasionally bromine is mentioned as occurring with it; but little has been published about it that is definite. The author proposed to determine the exact amounts of iodine, bromine and chlorine in some sponges from different sources, and specimens from Florida, Cuba and Bahama Islands were analyzed. The amounts of these elements in these specimens differ greatly, but the average percentages for 'the four specimens

examined are, viz.: iodine, .603; bromine, 1.307; chlorine, 1.06. When we consider the very small amount of bromine and the minute trace of iodine found in the water of the ocean, it is indeed remarkable that these animal organisms can thus select and collect them from the large portion of chlorine in the salt found there. We also note in this an explanation of the fact that these sponges can only grow in "open ocean water.'

Quantitative determination of potassium as bitartrate: SIGMUND WALDBOTT and FRED. W. WEISSMANN. This method was evolved in order to avoid the use of the expensive and difficultly accessible platinum chloride. It is applicable to mixtures of K- and Na-salts resulting from the regular analytical separation of other metals including Ca and Mg. Principle of procedure: To the neutral solution of K- and Na-salts add Nabitartrate in slight excess, evaporate to dryness, displace the water-soluble salts by means of water saturated with cream of tartar at or slightly below the temperature of the laboratory, then judiciously displace the cream of tartar solution by the careful addition of alcohol. A straight calcium chloride tube containing a plug of cotton is useful in these operations. Finally heat to 100° C. for 1 hour in a current of air, cool and weigh. Fair uniformity of temperature is essential for the accuracy of the method.

The properties of pyroxylin plastics: R. P. CALVERT and J. H. CLEWELL.

The extraction of potash salts from kelp charcoal: J. W. TURRENTINE, P. S. SHOAFF and G. S. SPENCER. The charcoal yielded by the destructive distillation of dried kelp is porous and readily yields its values, potassium and sodium chlorides and iodides when treated with hot water. In order to obtain a highly concentrated solution and at the same time efficient extraction, some counter-current system was found to be necessary. A solution of the problem was found in the adoption of a number of mechanical filter presses connected in series with each other and with leaching troughs interposed. The brine from one press is pumped into the leaching trough of the preceding one, while the press-cake from each press falls into the leaching trough of the succeeding one. Thus the brine is pumped up hill while the charcoal passes downward by gravity. The two streams passing in opposite directions counter-current extraction results. Filter presses of the revolving disk type and known as the American are employed. Filtration and washing are effected under vacuum and the press cake is broken loose by compressed air. The apparatus

shows high efficiency, is automatic and is regarded as eminently satisfactory.

"Kelpchar" a new decolorizing carbon prepared as a by-product in the extraction of potash from kelp: J. W. TURRENTINE, P. S. SHOAFF and G. C. SPENCER. Following the researches in the laboratories, respectively, of Dr. F. W. Zerban, of the Louisiana Sugar Experimental Station and of the Experimental Kelp Plant, of the United States Department of Agriculture, it was shown that a carbon of high activity could be produced in large quantities from kelp, depending on the method of retorting. One-stage retorting was efficacious, under certain conditons but did not yield a product of uniform or even dependable grade. Two-stage retorting, however, did yield a product of constant properties and made possible the large scale production. Accordingly this method was instituted pending the determination of the optimum conditions surrounding the one-stage operation. The product of the retorting or destructive distillation of kelp, a porous charcoal, is leached with hot water to remove potassium chloride and iodide and the residue, in the form of a press cake, is treated with the required amount of hot, dilute HCl to dissolve out soluble constituents and is then washed with water to neutrality. It is then dried and sacked for shipment. The tank system of extraction at present is in use. Acid proof construction is employed. The material is transferred from tank to tank in the sludge form by means of pumps, and spent acid and water are removed by filtering in situ over vacuum. The product compares favorably with Norit on molasses solution being equal in value and shows great usefulness when applied to materials of widely varying characteristics. It offers every promise ultimately of meeting the requirements of the chemical industry for a carbon of the highest grade.

CHARLES L. PARSONS,
Secretary

(To be continued)

THE AMERICAN ASTRONOMICAL

SOCIETY

THE AMERICAN ASTRONOMICAL SOCIETY THE twenty-third meeting of the society was held September 2 to 5, 1919, at the University of Michigan, Ann Arbor, where during the same week were also being held meetings of the Amercan Mathematical Society and of the Mathematical Association of America. Members of all three societies were housed at the Newberry Residence and at the Michigan Union, and the arrangements

demonstrated the ideal condition of gatherings where members live close together for several days. There were about seventy members and guests present at the astronomical sessions.

In opening the first session, Acting President Schlesinger referred to the great loss which the society had suffered since the last meeting in the death of Professor Edward C. Pickering, who had been president of the society for thirteen years, and who had been the leading figure at its meetings throughout that time. The society had also lost Professor Charles L. Doolittle, who had acted as treasurer from the founding of the society in 1899 until he retired in 1912. The following resolution, which had been passed by the Council, was endorsed as representing the sentiment of the members of the society, and was ordered to be printed in the publications.

The council of the American Astronomical Society records with regret the death on February 3, 1919, of EDWARD CHARLES PICKERING, who had been president of the society since December 30, 1905. His success in introducing new methods into the observatory, particularly with regard to the determination of the brightness and the spectra of stars, his extraordinary ability in carrying out large projects, and the extent and diversity of his experience and knowledge, have given him a permanent place among the great names in the history of science. The society will keenly feel the loss of his presence at its meetings. The members of the society had every reason to regard him as a warm friend, and to them the sense of personal loss is very deep.

The visitors at Ann Arbor were hospitably entertained by the University of Michigan, and especially by Director and Mrs. Hussey at the Observatory. There was also opportunity to join forces with the mathematicians at a smoker and a dinner. There was one joint meeting of the three societies, with the following program.

"Mathematics and statistics." Retiring address of the president of the Mathematical Association of America. Professor E. V. Huntington, Harvard University.

"The work of the National Research Council with reference to mathematics and astronomy." Professor Ernest W. Brown, Yale University.

"Reports on the International Conference of Scientists at Brussels."' Dr. Frank Schlesinger, Allegheny Observatory, Dr. L. A. Bauer, Carnegie Institution.

The time and place of the next meeting of the Astronomical Society was left to be determined by the executive committee.

Officers were elected for the ensuing year:

President-Frank Schlesinger.

Vice-presidents-George C. Comstock, Walter S.

Adams.

Secretary-Joel Stebbins.

Treasurer-Benjamin Boss.

Councilors-Ernest W. Brown, Otto Klotz, Solon I. Bailey, W. J. Hussey, Henry Norris Russell, V. M. Slipher.

The program of papers was as follows: Variations of type in the Cepheid variables l Carinae and n Aquila as shown by the general spectrum: SEBASTIAN ALBRECHT.

A systematic search for novæ at the Harvard Observatory: S. I. BAILEY.

On the change in the period of the variable star Bailey No. 33 in the cluster M5: E. E. BARNARD. Remeasurement of Hall's star in the Pleiades: E. E. BARNARD.

Variable stars in M 11: E. E. BARNARD.

On the varnishing of astronomical negatives: E. E. BARNARD.

Some observations of the total solar eclipse on May 29, 1919, at Cape Palmas, Liberia: L. A. BAUER. Hypersensitizing commercial panchromatic plates: S. M. BURKA. (Introduced by C. C. Kiess.) Some recent developments in the study of SS Cygni: LEON CAMPBELL.

The spectra of variable stars of long period: ANNIE J. CANNON.

Atmospheric refraction near the horizon: GEORGE C. COMSTOCK.

Studies of class B spectra having hydrogen emission: R. H. CURTISS.

Fluctuations in the moon's longitude in relation to meteorological variations: RALPH E. DELURY. Apparent relation between Chinese earthquakes and California tree growths, 0-1680 A.D.: RALPH E. DELURY.

Levels of the Great Lakes in relation to numbers of sun-spots: RALPH E. DELURY.

Simultaneous spectroscopic observations of the rate of rotation in north and south solar hemispheres: RALPH E. DELURY.

The periodograph and its application to variable
star periods and other problems: A. E. DOUGLASS.
On the eclipsing variables RT Persei and U Cephei:
R. S. DUGAN.

Preliminary results of a comparative test of the
100-inch and 60-inch telescopes of the Mount
Wilson Observatory: GEORGE E. HALE.
Rates of the standard sidereal clocks at the U. S.
Naval Observatory: J. C. HAMMOND AND C. B.
WATTS.

Note on the spectrum of Nova Aquila No. 3: W.
E. HARPER.

The orbit of the spectroscopic binary Delphini: W. E. HARPER.

The orbit of the spectroscopic binary Boss 4507: W. E. HARPER.

A desideratum in solving Kepler's problem: H. A.
HOWE.

The red and infra-red arc spectra of eight ele-
ments: C. C. KIESS AND W. F. MEGGERS.
Color-index of planets: EDWARD S. KING.
Photographic observations of the Great Nebula in
Orion: C. O. LAMPLAND.

Star tables good to the year 2000 for civil engineers and navigators: H. C. LORD.

Origin of the sun's heat: W. D. MACMILLAN.
False spectra produced by gratings: W. F. MEG-
GERS, C. C. KIESS AND F. M. WALTERS, JR.

Evidences of change in coronal structure during the eclipse of June 8, 1918: J. A. MILLER.

The masses of 32 visual binary stars: J. A. MILLER AND J. H. PITMAN.

Measures of double stars on photographs: CHARLES P. OLIVIER.

Shifting absorption at the heads of the brighter helium bands in the spectrum of y Argus: C. D. PERRINE.

Methods of asteroid observation and reduction:
GEORGE HENRY PETERS.

The great eruptive prominences of May 29 and
July 15, 1919: EDISON PETTIT.
Studies in prominence characteristics: EDISON
PETTIT.

The proper motions and parallaxes of 359 stars in the cluster h Persei: HANNAH STEELE PETTIT. The spectroscopic orbits and dimensions of the eclipsing variables U Ophiuchi, RS Vulpecula, and TW Draconis: J. S. PLASKETT.

Report on progress of work with the 72-inch telescope: J. S. PLASKETT.

Annular eclipse of the sun of 1919, November 22, as visible in the United States: WM. F. RIGGE. Direct micrometrical observations of the sun: E. D. ROE, JR.

The spectrum of the milky way: V. M. SLIPHER. All-American time: ELLIOTT SMITH.

Progress in photo-electric photometry: JOEL STEB

state and that the same broad underlying biological principles are applicable to both. Indeed there are some teachers who become so inspired with the idea of biology as the study of living organisms and with the prime importance of underlying biological principles that their students, pondering over the vague structures and intangible phenomena of a mysterious microscopic world, are led to lose sight completely of the fact that, after all, it is plants and animals they are dealing withsomething they have been familiar with all their lives.

There are some botanists and zoologists to whom a general biology course means something quite different from what has just been described. It means two virtually independent, but consecutively arranged and more or less closely coordinated courses, the one in plant biology or elementary botany, and the other in animal biology or elementary zoology: these two, alike in their pedagogical objects but different in their material, being grouped together for educational or administrative purposes. But this is not the sort of a general biology course with which the present article deals. We are concerned rather with the first-mentioned type-the type which, in no small degree at any rate, has been responsible for the popular delusion that biology is the study of animals: that the words biology and zoology are synonymous.

Through the influence of Martin and his students general biology obtained a rather strong foothold in this country. It has been widely adopted by the high schools and was given a place in the curricula of many colleges and universities. Abroad, however, so far as the higher institutions of learning are concerned, it was not so favorably received. "In the universities of Britain, Germany and in most cases of France," according to a prominent American botanist, "a biology course has never been admitted or regarded as of sufficient thoroughness." And even in our own country, as will be pointed out in detail presently, the number of institutions of college grade which offer a course in general biology has diminished greatly in recent time. To use the picturesque phraseology of

a noted contemporary botanist: general biology "is a kind of course introduced years ago by the Huxley and Martin book and discarded when botany became strong enough to stand on its own legs."

For a number of years it has been the conviction of the writer that a course in general biology of the type specified above ought not to be offered to elementary students, either as a cultural study or in preparation for more advanced work in botany or zoology. It has seemed particularly undesirable that in an institution having both a department of botany and a department of zoology such a course should be given by one department alone. With a view to ascertaining certain facts and securing a consensus of opinion regarding certain relevant problems, a questionnaire on this subject was recently submitted to 105 botanists, representing 67 colleges and universities, and to 65 zoologists, representing 49 similar institutions. Replies have been received from 86 botanists and 46 zoologists, representing altogether 66 institutions. The present article, in the main, is based on these replies and on a series of 19 letters relating to similar problems which was secured a number of years ago and courteously loaned to the writer by Professor Margaret C. Ferguson, of Wellesley College. To a very large extent the writer has acted merely in the capacity of editor or compiler in adapting and coordinating the various individual expressions of opinion set forth in these communications. Although quotation marks are seldom used, much of the subject matter in this paper has been quoted verbatim or with slight modification. For obvious reasons neither individuals nor institutions are referred to by name.

For present purposes American colleges and universities may be divided more or less naturally into two classes: Class A, those which maintain distinct departments of botany and zoology; and Class B, those in which both botany and zoology are under one head, the department of biology. Among the institutions investigated by the questionnaire, 47 of those heard from belong to class A, 19 to class B. Of those belonging to class A there