The greatest service of this method appears when the two sets of allelomorphs are combined. The student has learned to multiply a2+2ab+b2 by the expression x2 + 2xy + y2. He will perform the operation as one familiar to him and he can readily be taught to recognize the four pure strains a2x2, a2y2, b2x2, b2y2. Suppose a and y represent the dominant characters and b and x represent the recessives, emphasizing the fact that the dominant is effective whether appearing as the first or as the second power. Suppose a represent tallness and y represent red flower in a plant. Gathering the results of the multiplication according to visible attributes we have four columns representing the Mendelian ratio 9:3:3:1. such body of silica has impressed itself upon the writer during the preparation of a discussion of the acidic dikes of northern New York. Such terms as "quartz dikes " or " dike quartz" are not comprehensive enough, first, because much of the silica under consideration is not in dike form, and, second, because the silica may be either quartz or tridymite depending upon the temperature of crystallization. The term "selexite" is proposed for any body of pure or nearly pure silica of igneous or aqueo-igneous origin which occurs as a dike, segregation mass, or inclusion within or without its parent rock. This term is based upon the name "silex " used by Pliny in his "Natural History " for the mineral now known as quartz. "Silexite," therefore, not only has the advantage of simplicity as a name, but also it directly suggests the composition of the rock which it names. SMITH COLLEGE WILLIAM J. MILLER SILEXITE: A NEW ROCK NAME IN the granites of the Adirondack region the writer has observed many bodies of pure or nearly pure silica of igneous origin in the form of dikes segregation masses practically in situ, or inclusions. Among many other districts where similar masses of silica occur is the. Silver Peak quadrangle of Nevada in an account of which Spurr has described many considerable bodies of quartz of magmatic origin. Numerous fine examples of so-called "quartz dikes occur in the Holyoke quadrangle of western Massachusetts described by Emerson. The need for a definite name to apply to any THE WESTERN SOCIETY OF NATURALISTS THE Bay Section of the society held a two-day meeting at Stanford University, November 29-30, 1918. The sessions, held in Jordan Hall, were well attended and the various papers which were of more than usual interest were enthusiastically received. Dr. Joseph Grinnell served as chairman. An informal dinner Friday evening and a field trip on Saturday afternoon were features of the occa sion. Dr. S. D. Townley gave the evening lecture on "The recent solar eclipse." The following papers were presented: Isolation as a factor in species forming: DAVID STARR JORDAN, Stanford University. A Thanksgiving Day registration of plants in bloom on Mt. Tamalpais: ALICE EASTWOOD, California Academy of Sciences. Use of selective dyes in sanitary examination of water: IVAN C. HALL, University of California. The naturalist's place in his community: E. W. ALLEN, Fresno High School. Adaptation of the eyes of birds for rapid flight: J. R. SLONAKER, Stanford University. Intrauterine absorption of conceptsuses: A. W. MEYER, Stanford University. The relations between the salinity of water and the osmotic pressure of nereocystis: ANNIE MAY HURD, University of California. Gistel's natural history: DAVID STARR JORDAN. The English sparrow has arrived in Death Valley: J. GRINNELL, University of California. The Steinhart Aquarium of the California Academy of Sciences: B. W. EVERMANN, California Academy of Sciences Some phases of plant succession due to grazing: C. H. SHATTUCK, University of California. Larval stages of the Japanese blood-fluke, Shistosoma japonicum: W. W. CORT, University of California. Genetic investigations of the Compositæ: E. B. BABCOCK, University of California. New habitat groups in the museum of the California Academy of Sciences: B. W. EVERMANN. Demonstration of a plankton net: W. E. ALLEN. The discovery of some new white fishes in Bear Lake, Idaho: J. O. SNYDER, Stanford University. The work of the Committee on Zoological Investigation of the Council of Defense of California: B. W. EVERMANN. The Escalonias in Golden Gate Park: ALICE EAST WOOD. The five-toed kangaroo rats of west-central California: J. GRINNELL. Orthogenesis: DAVID STARR Jordan. Mussels of the Pacific Coast: E. P. RANKIN, U. S. Bureau of Fisheries. The ovulation and Estrus cycle in the rat: J. A. Bacteriology of peanut butter: IVAN C. HALL. What kinds of botany does the world need now: Papers were read for C. V. Taylor, Forrest Shreve and D. T. MacDougal, the authors not being present. THE TENNESSEE ACADEMY OF SCIENCE THE tenth meeting (seventh annual meeting) of the Tennessee Academy of Science was held on November 29, 1918, at Vanderbilt University, Nashville, Tenn., President John T. McGill presiding. The program was as follows: Memorial Sketch of Dr. A. H. Purdue, by Dr. L. C. Glenn. Annual address of the president, "Tobacco smoke; its composition and toxicity," by Dr. John T. McGill. A vocational survey of the chemical industries of Nashville, by Professor H. A. Webb. The effect of the Old Hickory Works upon Cumberland River water, by Dr. W. H. Hollinshead. Reelfoot Lake water, by Dr. J. I. D. Hinds. On the temperature of reduction with hydrogen, by Dr. J. H. Ransom and Dr. J. L. St. John. The sulphur industry in the United States, by Miss Gretchen H. Lee. The differential action of lime and magnesia upon the conservation of soil sulphur, by Professor W. H. McIntire. Carbocoal, a new smokeless fuel from high volatile coals, by Dr. C. H. Gordon. Geology as applied to warfare, by Wilbur A. Nel son. The contributions of biology to winning the war, by Dr. E. E. Reincke. Forestry and the war, by R. S. Maddox. Uses of meteorology in the war, by Roscoe Nunn. The geographic basis of the European war, by Professor A. E. Parkins. The migration of the birds of the Mississippi Valley, with special reference to Reelfoot Lake, by W. D. Howser. The future of the airplane, by Latimer J. Wilson. The election of officers for the ensuing year resulted as follows: President, Dr. L. C. Glenn, Vanderbilt University, Nashville, Tenn. Vice-president, Professor Scott C. Lyon, Southwestern Presbyterian University, Clarksville, Tenn. Editor, Dr. C. H. Gordon, University of Tennessee, Knoxville, Tenn. Secretary-Treasurer, Roscoe Nunn, U. S. Weather Bureau, Nashville, Tenn. SCIENCE FRIDAY, FEBRUARY 14, 1919 EDWARD CHARLES PICKERING By the death of Edward C. Pickering American science has lost one of its most distinguished figures, one of the most noteworthy contributors to its progress during the past forty years, and one of its most inspiring and influential leaders. A full account of his long and active career would demand far more space for its presentation and time for its preparation than are at the moment available; only the main events and achievements of an exceptionally productive life can be touched upon in these few words of appreciation. Born at Boston, in 1846, of an old New England family, and a graduate of Harvard of the class of 1865, after two years as instructor in mathematics, he became professor of physics at the Massachusetts Institute of Technology, where he established the first laboratory in America in which students were instructed by actual contact with physical instruments and measurements. Upon the death of Professor Winlock, the youngest physicist was called, in 1877, at the age of thirty-one, to the directorship of the Harvard College Observatory, which he held for nearly forty-two years, continuing the tradition of the institution, all of whose directors have died. in office. At this time most observatories were devoting themselves mainly to the old "astronomy of position"-the determination of the apparent positions of the stars and other heavenly bodies upon the celestial sphere, and of those constants of nature which can be derived from such observations and the "new astronomy" (now bet ter known as astrophysics) was in its infancy. It is characteristic cf Pickering that he realized at once in what direction the greatest opportunities lay, and set to work to employ the full resources of the observatory in fundamentally important work. Harvard had always been sympathetically inclined towards the newer developments of astronomical science, and considerable photometric work had been done under Bond and Winlock; but, when the new director began to devote the main portion of his own time, and that of the fifteen-inch telescope (then one of the greatest in the country) to photometric researches, considerable criticism was aroused. "Why," said these critics, "should observations with the meridian circle and micrometer, which yield results accurate almost to one part in a million, be neglected in favor of measures in which differences of five, or even ten per cent. habitually occur? Can such inaccurate observations be of any value in an exact science?" Undaunted by these cavils, he continued in his chosen course-with what abundant reason the nearly eighty volumes of the "Harvard Annals" which appeared during his directorate may testify. The "old astronomy" was not neglected-in fact, twenty years' time was spent by several members of the staff in preparing each of the two Harvard zones of the Astronomische Gesellschaft's scheme of international cooperation in star-cataloguing-but the astrophysical work accomplished under Pickering's directorship, and bearing the marks of his genius, is of incomparably greater volume and importance. He was a pioneer in several fields, in each of which he has had many followers. He was never contented with the unthinking adoption of the methods and instruments of investigation which he found in use, but was always designing new ones, In with a view to increasing the accuracy of observation, and, above all, to obtaining rapidity without sacrificing accuracy. the latter particular he was indeed a master. He possessed a genius for organization which would undoubtedly have brought him both wealth and fame in the world of business: but he preferred to devote these talents to the service of science, and, because of them, enjoyed work of a sort which most other men would have regarded as drudgery. He once said to the writer, "I like to undertake large pieces of routine work." In the great masses of such work done under his direction, the principles of "scientific management" were fully applied. All that could be done by assistants of moderate capacity was left to them, and the whole working time of the experienced specialists was devoted to such parts of the work as they alone could do. To extend the study to the stars of the southern hemisphere, a station was established at Arequipa, Peru, in 1890, and has been actively maintained ever since, and another has more recently been set up in the island of Jamaica. The results of these carefully reasoned plans have been so extensive that only the principal features can be mentioned here, leaving a host of minor but highly interesting investigations undescribed. In visual photometry, Pickering started almost de novo, devising new measuring instruments, with which observations of all the accuracy necessary for his purpose could be made with great rapidity-notably the meridian photometers, with which the brightness of stars is measured, as they cross the meridian, by comparison with some circumpolar star which is always available as a standard. With these instruments more than 45,000 stars have been observed at Cambridge and Arequipa, and the resulting system of visual stellar magni tudes has been generally adopted as an international standard. When to these observations, most of which were made by Professor Pickering himself, are added his numerous measures upon variable stars, satellites and other objects, the whole number of photometric settings which he personally made rises to the amazing total of more than a million and a half. He was also a pioneer in stellar photography, and especially in the use of the doublet lenses which combine great light grasp with a wide angle of field, and can with an exposure of an hour or two, record on a single plate the positions and magnitudes of a number of stars which may run into the hundreds of thousands. The Harvard equipment includes instruments of this type ranging from the 24-inch Bruce telescope at Arequipa and the 16-inch Metcalf instrument at Cambridge to the little lenses of one inch aperture which are used to photograph as large a portion of the visible heavens as possible on every clear night. The plates are developed, indexed, and filed in the great "Harvard Photographic Library,' ," which its creator described as "a library of 250,000 volumes, every one unique, and with but a handful of readers to work in it." The very magnitude of the mass of information stored in this vast collection makes it impossible to extract it all; but whenever an object of unusual interest is discovered, it is only necessary to refer to the Harvard plates to find out just where and how bright it was on some three or four hundred dates during the last thirty years. Among the most notable examples of this may be mentioned the recognition of images of the asteroid Eros upon plates taken two and four years before its discovery, and the recent tracing of the history of the brilliant new star in Aquila through an interval of thirty years, up to the very day before the great outburst. The third principal field of work is in stellar spectroscopy. Pickering led again in the photography of stellar spectra with the objective prism, and in the more precise classification of stellar spectra which this made possible. Assisted financially by the liberal aid of the Henry Draper Memorial, he and his very distinguished assistants, Mrs. Fleming and Miss Cannon, studied these spectra, devised the empirical classification of the original Draper Catalogue, and improved upon this by omitting some of the original classes and rearranging others, until the resulting classification proved so convenient, and so remarkably representative of the actual facts, that it was adopted without a dissenting voice by the International Union for Solar Research as a universal standard. The fact, which was first brought out by this investigation, and served as the basis of the final classification, that the spectra of almost all the stars fall into a single sequence, along which each type grades almost imperceptibly into the next, is now recognized as the very foundation of modern astrophysics, and the progress of discovery serves steadily to emphasize the importance of classification according to spectral type in the most diverse problems of sidereal astronomy. In this field, too, the Harvard work is of imposing extent, culminating in the "New Draper Catalogue" containing the spectra of about 215,000 stars, classified by Miss Cannon. Professor Pickering took the liveliest interest in this monumental work, and in the admirably arranged plans for its production; and it is cause for gratification that the first volume saw the light while he was alive to enjoy it. One other series of investigations that should not be passed over deals with photographic photometry. This was one of the chief interests of his later years, and an increasing part of the work of the observa |