west component rate of the falling meteorite can not at present be stated. It seems now to be pretty well established that the meteor never crossed to the west side of the Cincinnati Southern Railroad. For the forthcoming Bulletin of the Kentucky Geological Survey the writer has delineated upon a map of a portion of southeastern Kentucky the area in which all the fragments of the meteorite will probably be found. At present writing seven pieces ranging in weight from 13 oz. to 5 lbs. have been found that by their covering of glaze indicate that the split off from the main mass at a considerable distance from the ground. Fifty-two pieces weighing from less than an ounce up to four pounds have been found that are parts of a mass weighing originally about 31 pounds. This mass was broken into these numerous fragments as the result of falling on top of the conglomerate cliff which forms the walls of the gorge of the Cumberland River below the Falls. The larger fragments, which split off from the main mass at a considerable height, besides the covering of glaze, have the characteristic pittings of meteorites. They are light gray in color, and exhibit a brecciated structure. A chemical examination of the material of which they are composed, made by Dr. Alfred Peter, of the Kentucky Agricultural Experiment Station, shows it to be mainly the mineral enstatite (silicate of magnesium). Through this is disseminated microscopic particles of nickel-iron and iron combined with sulphur in an amount not exceeding two tenths of one per cent. Small amounts of sodium and calcium are also present. The meteorite would therefore be classed as chondritic aerolite. It has the same specific gravity as enstatite, 3.18. a ON THE AURORAL DISPLAY OF MAY 2, 1919 THE notes on this display, in SCIENCE, May 23, 1919, lead me to offer the following sum mary of my observations on it between 8:38 and 10:30 P.M. (75th meridian time), May 2. There were streamers of increasing prominence from the time I first observed the display at 8:38, until the culmination at 8:50 to 8:55, when the sky from the north-northwest to north by west was covered from about 10 degrees to a height of 45 or 50 degrees with a deep crimson light. The auroral arch, which was unusually narrow and sharply defined below, and at times subdivided in two or three parts, continued with varying brightness and altitude (base about 8 to 15 degrees) till 10:30, at least. There was some moderate streamer display from time to time. The effect of the auroral display was heightened by the sweep of searchlight beams from the south, and by the presence of the relatively new moon in conjunction with Venus. A very similar display was observed here February 27, 1919, from 8:50 till after 11 P.M., with crimson coloration in the north to an altitude of about 40° at 10:45 to 10:50. CHARLES F. BROOKS CHEVY CHASE, WASHINGTON, D. C. MEETING OF PLANT PATHOLOGISTS ON LONG ISLAND TO DISCUSS POTATO DISEASES THE summer potato inspection tour and conference arranged by the Advisory Board, American Plant Pathologists, will be held on Long Island from June 24 to 27, 1919 for the special purpose of studying potato mosaic and leaf roll. The members of the party will meet at the Griffen House, Riverhead, Long Island, Tuesday evening, for dinner, after which there will be a meeting at the Court House. The next day will be spent in a tour of inspection of test plots of potatoes on the north side from Riverhead to Orient Point. There will be an informal conference at Riverhead during the evening. On June 26, a trip will be made to the south side, the day being spent in the inspection of an experimental test plot at Wainscott, and in conferences at Southampton. The party will then take an evening train to Garden City, Nassau County. The following day, June 27, will be spent in the inspection of experimental plots at Glen Head and in visiting a few of the large truck farms for which Nassau County is famous. An evening meeting will be held at New York City. The experimental test plots consist of plantings of healthy, mosaic, and leaf roll seed tubers obtained from northern and central New York, Vermont, Maine, Long Island, Prince Edward Isle, and Bermuda. Records of the behavior during 1918 of the parent plants will be compared with the behavior this year of the progeny. Much of this seed has been planted under the direction of pathologists who have been investigating these diseases. An opportunity will also be afforded to compare fields planted with seed from the north and with Long Island grown seed; of fields planted with mature and with immature seed. Noted potato pathologists from the United States, Canada and Bermuda will be present to explain the various tests, to point out the characteristic symptoms, and to discuss the results observed here as well as other experiments they have conducted. The bearing of these observations and studies on seed certification will be given consideration at the conferences held during the tour. Invitations have been extended to a pathologist of England, of Ireland and of Holland, and some assurance has been received that one or more of these men will be present. It is expected by means of these observations and discussions that considerable light will be thrown upon the nature and behavior of these serious and baffling diseases and that thereby measures for control will be better understood. Every pathologist interested in potatoes or in these particular types of diseases should plan, if possible, to attend, for the occasion is unusual in material available for study and Horticulturists, in instruction presented. agronomists and other persons interested are invited to join the pathologists. Persons planning to attend should at once inform the writer in order that accommodations may be reserved for them. The farmers of Long Island have generously offered to pro vide the means of transporting the party about the island. M. F. BARRUS, Chairman, Committee of Arrangements SCIENTIFIC BOOKS Appendages of Trilobites. By CHARLES D. WALCOTT, Smithsonian Misc., Coll., Vol. 67, No. 4, Cambrian Geol. and Pal., IV., December, 1918, pp. 115-216+ index, Pls. 14–42, Text Figs. 1–3. In this recent paper Dr. Charles D. Walcott summarizes his investigations of the appendages of trilobites during the past forty-five years, a research undertaken in pursuance of a promise made to Professor Louis Agassiz in 1873. Since that time, he writes, "I have examined and studied all the trilobites that were available for evidence bearing on their structure and organization." His summary of 18812 is reviewed and corrected, together with later papers discussing his various discoveries in this subject.3 The highly organized trilobite, Neolenus serratus (Rominger). from the Burgess shale quarry opened by Dr. Walcott, near Field, B. C., several years ago, shows most graphically in the ten plates devoted to its illustration the highly specialized development of appendages, which is also figured in plates of the Ordovician trilobites, Isotelus, Triarthrus, Calymene and Ceraurus. In the figure of Neolenus the appendages include antennules, caudal rami, endopodites, epipodites, exopodites, exites and protopodites. The evidence of appendages is supplemented by numerous figured sections of Ceraurus and Calymene. 2 The Trilobite: New and Old Evidence Relating to its Organization, Bull. Mus. Comp. Zool., Cambridge, Mass., Vol. VIII., No. 10, 1881, pp. 191224, Pls. I.-VI. 3 Proc. Biol. Soc. Washington, Vol. IX., 1894, p. 94. Smithsonian Misc. Coll., Vol. 57, 1912, pp. 164, 208, Pl. 24, Figs. 1, 1a. Idem, 1911, Pl. 6, Figs. 1, 2; 1912, Pl. 24, Figs. 1, 1a; Pl. 45, Figs. 1, 2, 3, 4. Text-book Pal. (Zittel), Eastman 2d ed., 1913, Vol. I., p. 701, Fig. 1,343, p. 716, Figs. 1,376, 1,377. Smithsonian Misc. Coll., Vol. 57, 1912, pp. 149-153. After discussing the mode of occurrence, conditions of preservation, manner of life including method of progression, food, defense and offense, the author describes species with appendages, which include besides the genera already mentioned, Kootenia dawsoni (Walcott), two species of Ptychoparia including a new one P. permulta from the Burgess shale quarry, Odonotopleura trentonensis (Hall), Trinucleus concentricus Eaton, and an unidentified Ordovician crustacean leg. The work of C. E. Beecher with Triarthrus is reviewed in some detail, and a different conclusion arrived at in certain features. In section two of the paper the structure of the trilobite receives attention, the author again referring to Beecher and other writers including Jaekel, Beyrich, Barrande and de Volborth. He then discusses in detail the appendages, summarizing them as follows: Cephalic (1) Antennules, (2) antennæ, (3) mandibles, (4) maxillula, (5) maxilla. Thoracic: Abdominal: Caudal rami: Further comparisons are with the recent Anaspides tasmania G. M. Thomson, a Malacostracan from Tasmania, Koonunga cursor Sayce, and Paranaspides lacustris Smith, also the parasitic crustacean Cyamus scammoni Dall, illustrations of all of which are given. After the extraordinary interest of the finely developed specimens in the plates representing Neolenus, attention will be drawn by those of Isotelus, Triarthrus becki Green, and other Ordovician trilobites, together with the sections of Cambrian and Ordovician trilobites, and finally the author's conclusions as pressed by several diagrammatic restorations, also sketches of thoracic limbs of trilobites and recent crustaceans, crustacean limbs, and six plates of tracks and trails of trilobites, each adding evidence to the author's deductions as to the appendages. ex Some conclusions drawn are that the trilobite's appendages show him to have been a marine crustacean far more highly developed than would have seemed possible in a period so infinitely remote. In its younger stages of growth a free moving and swimming animal, it later became a half-bur rowing, crawling and sometimes swimming animal and moving at times with the flow of the tides and prevailing currents. Eggs have been found both within and free from the body. . . . It was at home on many kinds of sea-bottom and was able to ac commodate itself to muddy as well as clear water. It was intensely gregarious in some localities and widely scattered in others, depending upon local conditions, and habits of the various species. Trilobites had an ample system of respiration by setiferous exopodites, epipodites, and exites attached to the cephalic, thoracic and abdominal limbs [as shown in restorations of the limbs on plates 34 and 35]. The structure of the gnathobases of the cephalic limbs indicates soft food such as worms, minute animal life and decomposed algæ. . . . The trilobite persisted from far back in pre-Cambrian time to the close of Carboniferous time . . . and left its remains more or less abundantly through about 75,000 feet of stratified rocks. The paper is profusely illustrated and carefully indexed. G. R. BRIGHAM SPECIAL ARTICLES PRESOAKING AS A MEANS OF PREVENTING In the course of investigations on the bacterial black-chaff disease of wheat, under the direction of Dr. Erwin F. Smith, a new method of seed treatment has been discovered which practically eliminates seed injury due to the use of disinfectants, and at the same time renders pathogens on the seed coats more susceptible to the action of the disinfectant. This is accomplished by allowing the seeds to absorb water for a definite period in advance of treatment. The saturation of the cells and cell-walls with water before treatment, by diluting the full-strength disinfectant beyond the point of injury as it enters the tissues, in accordance with the law of diffusion of dissolved substances, is the explanation of the results obtained. Not only is injury to germination prevented, but the germination of seeds thus treated is stimulated, reducing the danger of seed infection by soil organisms during the sensitive period of germination. On the other hand, experiments with wheat seeds infected with the black-chaff organism have shown that this method used with formalin will completely destroy the organism on the kernels. After screening and fanning to remove shrivelled grains, the treatment should be made by soaking infected seeds for ten minutes in water then draining and keeping moist for six hours. They are then soaked ten minutes in formalin 1:400 solution (1 lb. to 50 gallons of water) drained, and covered for six hours; then dried over-night and planted next day. If copper sulfate is used, the presoaked seeds are thoroughly wetted in the 1:80 solution (1 lb. to 10 gallons of water) for ten minutes, drained and kept moist twenty minutes, plunged for a moment into milk of lime, dried over-night and planted. The effect of the presoaking with water, besides preventing seed injury, is to stimulate dried and dormant bacteria on the seed coat, into vegetative activity, thereby rendering them more sensitive to the action of the disinfectant which must be applied at the end of the presoak period and of course before the seeds have begun to germinate. This is fully in accord with the established principle that microorganisms in a vegetative condition are more susceptible to destructive agents than when dry and in a resting stage. The effect of the presoak method of seed treatment with chemical disinfectants is, therefore, two-fold-first, seed injury is prevented by the dilution of the disinfectant as it enters the presaturated seed tissues; second, the efficiency of the disinfectant on the pathogen is increased. In view of the fact that nine different varieties of wheat, also oats, barley and maize, have been treated by this method, using both formalin and copper sulfate, disinfectants of widely different chemical nature, in strong solutions (formalin 1:320 and copper sulfate 1:80) without appreciable injury to germination, it appears probable that the same physiological principles here utilized can be applied to other chemical disinfectants and to the treatment of other seed-transmitted diseases amenable to control by these disinfectants, with variations of course in the length of the presoak period (which is six hours for wheat, barley and oats, and ten to eighteen hours for maize) and of the subsequent disinfectant period, as found necessary for each kind of seed and pathogen. The use of this method in farm practise involves no radical change in present procedure other than to keep seeds moist for definite periods before treatment. If the use of the presoak method is found efficient for the cereal smuts and other diseases as well as for the black-chaff disease of wheat, it will result in a saving of most of the seed now lost by present methods of treatment and also in increased germicidal efficiency. The formulation of this method, as here reported and later to be given in detail, opens up a wide field for the reinvestigation of practical seed treatment for the control of seed-transmitted diseases by chemical disinfectants. HARRY BRAUN LABORATORY OF PLANT PATHOLOGY, U. S. DEPT. OF AGRICULTURE THE AMERICAN PHILOSOPHICAL SOCIETY THE annual general meeting of the society was held from April 24 to 26 and a program of over fifty papers covering a wide range of subjects was presented. The sessions were presided over by the president, Professor W. B. Scott and by vice-presidents G. E. Hale, H. L. Carson and A. A. Noyes. Two important features were a symposium on the solar eclipse of June 8, 1918, and one on chemical warfare. In the former special attention was given to photographs and their interpretation of the prominences and the coronal arches and streamers obtained by members of the several expeditions sent from the Lick, the Mount Wilson, the Lowell, the Sproul and the Yerkes observatories. PROGRAM Thursday Afternoon, April 24, 2 o'clock William B. Scott, D.Sc., LL.D., president, in the chair The cosmic force, radio-action: MONROE B. SNYDER, director of the Philadelphia Observatory. The conservation of the natural monuments (illustrated): JOHN M. CLARKE, director of depart ment of science and State Museum, Albany, New York. Detection of ocean currents by their alkalinity (illustrated): ALFRED G. MAYOR, director of department of marine biology, Carnegie Institution of Washington, Princeton, N. J. Ocean currents moving from warm into cold regions are relatively alkaline and their surface waters absorb CO, from the atmosphere so slowly that they remain more alkaline than one would expect from their temperature. Conversely cold currents moving into warmer regions retain their relative acidity and part with their CO, at so slow a rate that they become warmer than would be expected from their low alkalinity. In tropical regions of the Pacific the surface currents sometimes observed setting toward the eastward, against the prevailing westerly drift, are relatively acid and contain more CO, than we would expect from their temperature. The hydrogen-ion concentration of sea water can so easily be detected by using such indicator as thymolsulphonephthalein that the method may prove of service to navigation in detecting the presence of counter currents before the ship has been deflected from its course. Some oceanographical results of the Canadian Arctic expedition 1913-18: VILHJALMUR STEFANSSON, commander of Canadian Arctic Expedition. (Introduced by Mr. Henry G. Bryant.) Evolution and mystery in the discovery of America: EDWIN SWIFT BALCH, of Philadelphia. Benjamin Franklin's art as applied to books for elementary teaching (illustrated): CHARLES R. LANMAN, professor of Sanskrit, Harvard University. The energy loss of young women during light household muscular activities (illustrated): FRANCIS G. BENEDICT, director of Nutrition Laboratory (Boston) of Carnegie Institution of Washington, and ALICE JOHNSON. To supply exact information regarding the energy requirements for light household work, the Nutrition Laboratory has begun a study of the heat of women engaged in various domestic activities. The subjects thus far studied have been young women from the domestic science department of Simmons College, approximately 200 women taking part in the experiments. The apparatus used for determining the carbon-dioxide production was a large respiration chamber in which 25 or more individuals could be studied simultaneously. The chamber was well ventilated by forcing outdoor air in at one end and withdrawing the chamber air from the other. A certain proportion of the outcoming air was passed through purifiers which absorbed the carbon dioxide. By noting the gain in weight of these absorbers, a measure of the carbon dioxide given off by the young women could be obtained. The heat production or energy loss was then calculated from the carbon-dioxide production. In all, 12 experiments were made, covering 50 periods 20 or 25 minutes in length. To provide a standard for computing the increase in energy required for the particular household occupation studied, the energy loss of the groups of young women while sitting quietly reading two hours after a light breakfast was determined at the beginning of every experi ment in from 1 to 3 periods. As a result of 23 rest periods on 12 experimental days, it was found that the average heat output per kilogram per hour was 1.12 calories. This average figure of 1.12 calories has a specific interest in that it indicates the probable heat production of women sitting quietly under ordinary living conditions with a moderate amount of food in the stomach. The relative contribution of the staple commodities to the national food consumption: RAYMOND PEARL, professor of biometrics, school of hygiene and public health, Johns Hopkins University. Hygiene and sanitation as improvised in the zone of operations during the Great War: BAILEY K. ASHFORD, surgeon, U. S. Army. (Introduced by Dr. W. W. Keen.) Bloodless removal of foreign bodies from the lungs through the mouth by bronchoscopy (illustrated): CHEVALIER JACKSON, attending laryngologist, Jefferson Medical College, Philadelphia. (Introduced by Dr. W. W. Keen.) Friday, April 25, 10 o'clock William B. Scott, D.Sc., LL.D., president, in the chair The new discoveries of extinct animals in the West Indies and their bearing on the geological history of the Antilles (illustrated): WILLIAM D. MATTHEW, curator of American Museum of Natural History, New York. During the last ten years, explorations in Porto Rico and Cuba have secured the fossil remains of various extinct animals from cave and spring deposits on the islands. Quite large collections have been obtained and it has been possible to reconstruct the entire skeleton of the largest animal found, a ground sloth about the size of a black |