DR. BENJAMIN PALMER CALDWELL, formerly of Tulane University, New Orleans, and for the past three years professor of chemistry in Oglethorpe University, Atlanta, has accepted the professorship of analytical chemistry in the Polytechnic Institute of Brooklyn, and will begin his work there in the autumn.

Ar the University of Saskatchewan, Assistant Professor L. L. Dines has been promoted to a full professorship of mathematics.

DR. ALEXANDER MCPHEDRAN has resigned the professorship of medicine in the University of Toronto medical department, and Dr. Duncan A. L. Graham has been appointed his successor. The Journal of the American Medical Association states that recently Sir William Osler invited professors of medicine in the United Kingdom to a dinner in Dr. Graham's honor, at which it was stated that Dr. Graham was the first whole-time professor of medicine appointed in the British empire. The appointment was made possible by the munificence of Sir John Eaton, Toronto. As a result all physicians in the service of the medical department at the university will resign, so that Dr. Graham will have a free hand in selecting his own staff.

DR. F. A. LINDEMANN has been appointed to succeed Professor Clinton in the chair of ex

by clouds, the meteor made its presence known by violent detonations, accompanied by the spalling off of fragments. The first of these fell near Sawyer P. O., not far from the Fallsof-the-Cumberland.

The concussions produced by the bolide were terrific, causing buildings to rock, and producting the impression on some that the region was being visited by an earthquake. The first news of the phenomenon printed in the local papers so recorded it. Realizing that the detonations heard and shocks felt were due to the concussions produced by a falling meteorite the writer through the medium of these local papers, and by correspondence with postmasters and telegraph operators throughout the district affected has succeeded in determining the path of the meteor and has secured a number of the fragments. The main mass appears to be yet undiscovered. Falling in the most rugged and sparsely settled portion of southeastern Kentucky the prospects of this main mass being found are not promising.

The general azimuth of the meteor in its fall seems to have been about north 30 degrees west. Over Kentucky it paralleled roughly the line of the Cincinnati Southern Railroad. An interesting incident in this connection is the record of the progress of the meteor kept

Oxford.

DR. S. W. J. SMITH, F.R.S., assistant professor at the Imperial College, South Kensington, and for many years secretary of the Physical Society of London, has been elected to the Poynting chair of physics in the University of Birmingham.

DISCUSSION AND CORRESPONDENCE

THE CUMBERLAND FALLS METEORITE

On April 9, last, a brilliant meteor was seen at mid-day to fall in a northwesterly direction across northeastern Tennessee. Though the sun was shining in this section, observers describe the light from the meteor as exceeding the sun in brightness. Passing over southeastern Kentucky, where the sky was obscured

the railroad stations and signal towers. They actually put it on a schedule something like an "extra," and heralded to operators ahead the arrival opposite them to the east of this

mysterious visitor. The operator on another

branch of the Southern Road at Coal Creek Tennessee saw the meteor disappear to the northwest at 12:21 P.M. The tower man at Tatesville, Ky., heard violent detonations to the east, and felt his tower rock at 12:27. Telephoning ahead to the Danville, Ky., operator, while yet talking to him he heard him reply at 12:30 "I hear it coming now." The distance from Tatesville to Danville in an air line is 48 miles. It took the meteor sounds, therefore, 3 minutes to travel this 48 miles. How much of this is due to the rate of sound traveling in air and how much to the north

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.

ARTHUR M. MILLER

DEPARTMENT OF GEOLOGY, UNIVERSITY OF KENTUCKY, May 14, 1919

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 in instruction presented. Horticulturists, 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. 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.

94.

3 Proc. Biol. Soc. Washington, Vol. IX., 1894, p. 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-burrowing, 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 accommodate 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].

SPECIAL ARTICLES

PRESOAKING AS A MEANS OF PREVENTING
SEED INJURY DUE TO DISINFECTANTS
AND OF INCREASING GERMI-
CIDAL EFFICIENCY

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,
BUREAU OF PLANT INDUSTRY,

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