S. J. JOHNSTON, formerly professor of zoology in the University of Sydney, Australia, died on July 16.

PROFESSOR H. H. HILDEBRANDSSON, the well-known Swedish meteorologist, recently died at the age of eighty-seven years.

PROFESSOR A. A. FRIEDMANN, director of the Central Geophysical Observatory of Russia, died on September 16, aged thirty-seven years.

ACCORDING to the Journal of the American Medical Association, the foreign guests at the fifteenth annual meeting of the clinical congress of the American College of Surgeons, Philadelphia, which takes place from October 26 to 30, will be Lord Dawson, of Penn, London, physician in ordinary to the king; Sir William Arbuthnot Lane, London, who will deliver the John B. Murphy oration in surgery; Professor Vittorio Putti, Bologna, Italy, who will speak on some phase of orthopedic surgery; Dr. Victor Pauchet, of Paris, professor of clinical surgery in the School of Medicine at Amiens, will read a paper on "Experiences in the surgical treatment of gastric, duodenal and jejunal ulcers"; Dr. William Blair-Bell, professor of obstetrics and gynecology at the University of Liverpool, England, and Dr. Philip J. Franklin, London, eye, ear, nose and throat surgeon to the East London Hospital. Headquarters will be at the Bellevue-Stratford Hotel. At the meeting on Monday evening the president of the congress, Dr. Charles H. Mayo, Rochester, Minn., inducted into office his successor, Dr. Rudolf Matas, of New Orleans.

THE Rochester Section of the American Chemical Society, in cooperation with the division of organic chemistry, will hold a symposium on organic chemistry in Rochester on December 29, 30 and 31. A number of the leaders in various branches of organic chemistry have been invited to present papers at the symposium. Ample time will be allowed for the presentation and discussion of the papers. This will make possible the presentation of papers of greater general interest to organic chemists than those which can be presented at the regular meetings of the division. All who are interested in organic chemistry and can attend the symposium are cordially invited to do so. Further particulars can be obtained from E. M. Billings, secretary, Rochester Section, Eastman Kodak Co., Rochester, N. Y., or F. C. Whitmore, secretary, division of organic chemistry, Northwestern University.

THE annual meeting of the Eastern Society of Anesthetists is being he'd at Philadelphia from October 26 to 30 at the Hotel Adelphia. There will be clinics in the mornings and discussions open to members of

the profession in the afternoons, also joint sessions with the Mid-Western Association of Anesthetists, the Philadelphia Academy of Stomatology and the American Society of Regional Anesthesia. The dinnerdance was held on October 28. Dr. Adolph F. Erdmann delivered the president's address on October 26.

THE New York State Association of Public Health Laboratories will hold its mid-year meeting on Wednesday, November 4, at the State Laboratory in Albany. There will be a morning and an afternoon session at which papers will be presented and opportunity given for general and informal discussion.

THE fifth annual conference of health officers and public health nurses will be held in Lansing, Michigan, on November 18, 19 and 20, under the auspices of the Michigan Department of Health and the Michigan Public Health Association.

MAYOR BEHRMAN, of New Orleans, has issued formal invitations to a conference to the mayors of thirty cities in Louisiana, Mississippi and Alabama and to the presidents of police juries in fourteen parishes in Louisiana, to make plans for a comprehensive survey to determine the best methods of attacking the problem of marsh mosquitoes. Governor Fuqua has issued invitations to the conference to the governors of adjoining states, the secretary of agriculture, the surgeon general, U. S. Public Health Service, and other federal sanitation experts.

AT the twenty-eighth annual convention of the American Bakers' Association held at Buffalo from September 15 to 18, the organization of a department of nutritional education in the American Institute of Baking, and the subscription of $100,000 in five installments of $20,000 a year toward financing the work of the department by the Robert Boyd Ward Fund, Inc., were announced. The contribution of $100,000 is without any conditions, the particular use of the money being left entirely to the determination of the directors of the institute. In the letter of Mr. W. B. Ward, president of the Robert Boyd Ward Fund, Inc., transmitting the first installment of $20,000, he expresses the hope that the idea of such a department may appeal to others in the industry and its allied trades so as to result in its further expansion and "that the work in the education and science of nutrition will redound to the credit of the industry as a whole."

A NEW type of institute was recently dedicated at Göttingen as the sixteenth institute of the Kaiser Wilhelm Society for Advancement of the Sciences. According to Industrial and Engineering Chemistry, this institute is to study all manner of air and water currents in free flow, in connection with airships, me

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teorological problems, the influence of currents on living organisms, etc. Although it has primarily no t direct relation to chemistry, nevertheless various questions which will be submitted to the institute may be of significance to chemical technology as well. Apparatus of an entirely novel type has been erected, for example, a large wind chamber pumped free of air, into which can be introduced powerful air currents of a velocity even greater than that of sound.

THE cornerstone of the new, building of the New York Academy of Medicine will be laid on October 30, at 4:30 o'clock. According to the Journal of the American Medical Association, from 1843 until 1924 the academy limited its activities to promoting the science and art of medicine, to the maintenance of medical library and the promotion of public health. When it decided to expand, the Carnegie Corporation appropriated $1,550,000 for a new academy building and the Rockefeller Foundation $1,250,000 for endowment for new activities, including the appointment of a full-time director and a new executive librarian, the development of library service, the maintenance of a bureau of clinical information and the publication of a bulletin. The director of the academy, who began his duties January 1, 1924, is a member of all committees, makes special studies of affairs suggested by the council and is general superintendent of the building. The library is the only public medical library in New York City. It is open daily to the public, and the staff will be increased in order to extend its activities.

It is reported that forty men, including carpenters, masons and electricians, left Oslo, Norway, on October 13 for Kings Bay, Spitzbergen, where they will spend the winter building a shed for Captain Roald Amundsen's polar airship. Mr. Ellsworth, Amundsen's colleague in this year's flight, has given $100,000 for the expenses of the expedition, which will be known officially as the Amundsen-Ellsworth Expedition. It will fly the Norwegian flag only. Captain Amundsen is now on a lecturing tour in the United States. His proposal is to fly in an airship next summer from Spitzbergen, by way of the North Pole, to Alaska. His experience this year has convinced him, he stated recently, that aeroplanes are not suitable for prolonged Arctic flights.

THE installation of new equipment in Professor Pavlov's physiological laboratory has been completed. The entire laboratory has been constructed according to plans worked out by Pavlov, and includes an operating department, consisting of three rooms and a clinic built in accordance with the latest requirements in clinical surgery. In one of the rooms has been installed a special sound-proof chamber for the

purpose of carrying on precise experiments on the method of conditional reflexes.

MT. WATATIC has been purchased by the New England Federation of Bird Clubs and will be presented to the Commonwealth of Massachusetts for a permanent bird sanctuary. Mt. Watatic is almost the only remaining important forest area of red spruce in Massachusetts. It is located in Ashburnham and Ashby. About one hundred acres on top of the mountain were bought by the federation when it was discovered that this virgin forest was about to be invaded by the axe. Negotiations were already in progress for the sale of it to a lumber concern when it was purchased by the Federation of Bird Clubs.

Museum News states that the first unit of the new museum of the Los Angeles Museum of History, Science and Art is now practically complete and it is hoped that the new building will be thrown open to the public by November 1. This four-story unit, which has been erected at a cost of $900,000, will provide approximately three times the floor space available in the old building. Until the other units are completed the exterior will be finished in concrete. Eventually the completed museum will be surfaced with stone. The opening of the new building will be marked by the unveiling of notable new habitat groups, more especially the great African jungle groups for which the material has been gathered during the past five years by Leslie Simpson, big game hunter. Two of these groups, one of which represents a water-hole on the veldt, will be one hundred feet long. Maurice Logan, who has painted the backgrounds for these groups, went to East Africa more than a year ago to make studies and photographs and to bring back material to be used in the construction of the settings. Among the collections which will find. a place in the new unit are: the Burlingame-Johnson Chinese potteries; paleontological and natural history collections; an extensive marine exhibit; the open-air gallery of garden and architectural sculpture.

AWARDS have recently been made of the four war memorial scholarships offered annually by the Westinghouse Electric and Manufacturing Company as ȧ memorial to those employees of the company and its subsidiaries who entered the service of their country during the World War. Each scholarship carries with it an annual payment of $500 for a period not to exceed four years, such payment to be applied toward an engineering education. This year's awards go to Bernard C. Hibler, who will attend Penn State College; Robert G. Redhead, Washington University, St. Louis; William H. Hamilton, University of Pennsylvania, and Starling Winters, University of California. Thirty-six candidates in ten cities competed.

A NEW journal, Genetic Psychology Monographs, has been founded at Clark University in order to fulfill a need long felt by American and European psychologists. The new journal has been formed to care for research papers that are too large to be printed in regular journals. Each number is to be a complete research and may be contributed from any part of the world. The journal is edited and published by the Pedagogical Seminary and Journal of Genetic Psychology, with an international board of editors consisting of: Bird T. Baldwin, State University of Iowa; William H. Burnham, Clark University; Cyril Burt, University of London; Edward Claparède, University of Geneva; Edmund S. Conklin, University of Oregon; Arnold Gesell, Yale University; William Healy, Judge Baker Foundation; Walter S. Hunter, Clark University; K. S. Lashley, University of Minnesota; Carl Murchison, Clark University; Henri Pieron, University of Paris; Sante de Sanctis, University of Rome; William Stern, University of Hamburg; Lewis M. Terman, Stanford University; E. L. Thorndike, Columbia University; John B. Watson, New York City, and Helen Thompson Woolley, Columbia University. There will be six numbers a year, each of one hundred pages and comprising a single research work, the first issue to be out in January.

YALE UNIVERSITY has set aside 200 acres of the Ray Tompkins Memorial tract near the new golf course as a preserve for the native plant and wild life of this region. The preserve will serve as a sanctuary for animals and plants and will also be used for field studies and instruction by the departments of botany, zoology and forestry. For a long time this extensive tract of forest has been under excellent protection and care. Around a portion of it is still found the high woven wire fence which confined the deer and elk when its former owner, John M. Greist, of New Haven, used the land as a deer park. In commenting upon the project, Dean Graves, of the forestry school, said: "Characterized by a great variety of trees, shrubs and wild flowers, already a refuge for birds and animal life of interest to the zoologist, and within easy reach of the university, the preserve offers an unusual opportunity for research and for class work in the field."

UNIVERSITY AND EDUCATIONAL NOTES

THE will of the late James B. Duke, former president of the American Tobacco Co., provides $40,000,000 for Duke University, Durham, N. C., $4,000,000 of which is to be used for the establishment of a medical school and hospital. This amount is in addition to the $40,000,000 given to Duke University last December by Mr. Duke.

ANNOUNCEMENT has been made by the Board of Trustees of Princeton University of the receipt of gifts amounting to $721,085 for general endowment and of $32,300 for current expenses. The trustees also accepted from an anonymous Princeton alumnus a trust fund of $50,000.

THE Connecticut College of Pharmacy, founded by the State Pharmaceutical Association, will be opened on October 21 in the old Yale Medical School Build

ing on York Street, which has been remodeled. A two-year course, leading to a degree of Ph.G., will be given.

DR. BASHFORD DEAN, curator of arms and armor at the Metropolitan Museum, and formerly professor of zoology in Columbia University, has been appointed professor of fine arts at New York University.

DR. JOHN RICE MINER has been appointed biometrician, with the rank of associate professor, in the Institute for Biological Research of the Johns Hopkins University.

DR. HAROLD W. MANTER, of the University of Illinois, has been appointed to the position of parasitologist in the department of zoology at the Louisiana State University, Baton Rouge.

FRANKLIN J. BACON, head of the department of pharmacognosy for Eli Lilly and Company, has been appointed head of the department of pharmacology and pharmacognosy in the College of Pharmacy at the University of Florida.

FRANKLIN SHERMAN, of the North Carolina State College, has been appointed head of the division of entomology at Clemson College, S. C.

THE following additions to the faculty of the Jefferson Medical College, Philadelphia, have been announced: Dr. Pascal Brooke Bland, professor of obstetrics; Dr. William M. Sweet, professor of ophthalmology, and Dr. Edward A. Strecker, professor of nervous and mental diseases.

DR. ARTHUR H. RUGGLES, director of the Butler Hospital of Providence, R. I., has been appointed consultant in mental hygiene to the department of university health and lecturer in psychiatry in the School of Medicine at Yale University.

ARTHUR N. BRAGG, assistant in biology in the Johns Hopkins University, has been appointed instructor in the department of zoology in Marquette University, Milwaukee.

M. RECHON has been appointed professor of electroradiology at the University of Bordeaux, to take the place of the late Professor Bergonié.

DISCUSSION AND CORRESPONDENCE PRESSURE ENERGY IN AN INCOMPRESS

IBLE FLUID AND BERNOULLI'S

PRINCIPLE

PROFESSOR E. H. KENNARD in SCIENCE for September 11 gives a correct statement of the "energy transfer" formulation of Bernoulli's principle, but it seems to me that he is mistaken in his contention that the "pressure energy" point of view is absurd.

In an open body of incompressible liquid under the action of gravity the potential energy per unit volume of a given portion of the liquid is, of course, partly dependent on gravity, and it is permissible to think of it as partly due to pressure. The first part of the potential energy per unit volume is equal to hdg where h is the height of the given portion above a chosen reference level, d is the density of the liquid, and g is the acceleration of gravity; and the second part of the potential energy per unit volume is equal to the pressure p of the portion of the liquid.

Let us take the pressure at the surface of the liquid as zero so that the pressure p at any point in the liquid may be thought of as gauge pressure. Then to carry unit volume of the liquid from the surface to a place where the pressure is p an amount of work equal to p must be done in overcoming the forces exerted on the unit volume by the surrounding liquid. This work has been handed on to other portions of the body of fluid (it does not reside in the portion of fluid which has been carried from A to B), but the location of what we choose to call potential energy is never a matter for consideration. The notion of potential energy is legitimate when the work done to effect a change of configuration is a function only of the change of configuration.

It is, of course, entirely proper to consider where the work done on a portion of fluid to carry it from A to B has gone to, that is to say the energy aspects of a fluid in motion can be formulated on the basis of transfer of energy in the fluid, and there is some advantage in this method because it involves definite things which are ignored in the method in which we assign potential energy due to pressure to each portion of the fluid. Potential energy is always an idea which makes up for things ignored.

MASSACHUSETTS INSTITUTE OF TECHNOLOGY

WM. S. FRANKLIN

IN an article on Bernoulli's theorem (SCIENCE, Sept. 11, 1925) Dr. Kennard objects to the name pressure energy for the so-called pressure head, and especially to the idea that a pound or a cubic foot of

liquid carries pressure energy with it along a tube of flow.

The validity of the objection can not be tested conclusively by deriving the theorem from the principle of energy, because this involves the point in question. Let Bernoulli's theorem be obtained as an integral of Euler's equations in the case of irrotational, frictionless, stream-line flow; it is then merely a mathematical affair awaiting any useful and usable interpretation. Two of the terms in it are kinetic and position energy, one depending on the velocity and the other on the position of the element of liquid. The third term is energy and since it depends on pressure the name pressure energy is surely not inappropriate. Every one of the three terms varies with the mass and the position of the element; therefore each quantity of energy may at least be regarded as belonging to and traveling with the element.

Pressure energy in this sense is distinctly different from compression or elastic energy. For example, if a rod is to be used for transmitting a push P with a possible displacement p, the pressure energy possessed by the rod is Pp; this is like potential energy Wh. If P shortens the rod an amount e the compression energy is 2Pe. Similarly, when energy is transmitted by water flowing through a horizontal pipe, the input, omitting the kinetic energy, is p/w ft-lbs per lb, the friction loss is h, ft ft-lbs per lb, and the output is thus (p/w - h1) vAw ft-lbs per sec. where v is the velocity of flow, A the section area of the pipe, w the specific weight of the water, and p the pressure (force per unit area) at the input end of the pipe. Problems solved in this way become simple exercises in book-keeping on the energy transactions of a pound of water.

Dr. Kennard's value of 46 ergs should be 23 ergs, because the average pressure is half of 1.031 × 10o dynes per cm.2

STEVENS INSTITUTE OF TECHNOLOGY

R. F. DEIMEL

A FOSSIL FISH OF THE FAMILY
CALLICHTHYIDAE

IN the fresh waters of South America north to Panama may be found small catfishes (Hoplosternum punctatum Meek and Hildebrand) of a peculiar type, the sides of the body covered with a double series of vertically elongated plates. They were revised by Mrs. Marion Durbin Ellis in 1913, and since then not much has been added to our knowledge. When recently collecting fossil insects in the green Tertiary rock at Sunchal, Province of Jujuy, Argentina, I was fortunate in finding the first fossil representative of the family. Although it is at least sev

eral millions of years old, it appears to belong to the living genus Corydoras, and may be known as Corydoras revelatus n.sp. It is 27 mm long from end of snout to base of caudal fin, the total length at least 31 mm; depth at base of dorsal slightly over 9 mm; width of orbit 2 mm; orbit from top of head 1.8 mm, from end of snout 3.5 mm; lateral plates numerous, certainly over 20 in each series; dorsal spine very strong, anal spine weak. In the deep body, arched profile of head, and rather large eye it resembles C. paleatus (Jenyns), a species discovered by Darwin on the voyage of the Beagle. The eye appears to be placed lower down, but this may be the result of crushing. The opercular plate agrees with that of C. paleatus and other species, having the lower posterior margin concave. The dorsal spine is very heavy, suggesting C. armatus (Günther), but there is no evidence that the soft rays are prolonged to a point.

The discovery of this fish, together with that of the accompanying insects, shows that the variegated green and red shales of this part of Argentina belong to the Tertiary, possibly late Tertiary, and are of freshwater origin. This is a matter of considerable importance as the age of the beds was somewhat in doubt. The discovery of fossil insects in these rocks is due to Mr. Geo. L. Harrington; my wife and I visited the locality and obtained many species. Corydoras still lives in the same region; thus C. micracanthus of Regan was discovered at Salta. T. D. A. COCKERELL

UNIVERSITY OF COLORADO

TOBACCO AND TOMATO MOSAIC

(1) LONGEVITY OF THE VIRUS OF TOBACCO MOSAIC IN February, 1920, I received from Dr. H. A. Allard for comparative tests a small bottle of expressed juice from mosaic-diseased tobacco plants. It was unfiltered and protected from contamination by a layer of toluene. A small portion only was used at the time and the remainder tightly corked and set aside.

On May 25, 1925, four healthy plants were inoculated by rubbing two leaves of each with a small portion of the preserved juice. Two check plants were treated similarly, using sterile water. The plants were kept in a good light in the laboratory. On June 15 each of the four plants was definitely mosaic-diseased, while the two check plants were perfectly healthy, as they have remained to date.

On June 25 four other healthy plants six weeks old were similarly inoculated and left in the greenhouse, while check plants were again treated with sterile water. On July 10 each of the four inocu

lated plants was showing excellent mosaic symptoms, while checks were healthy.

It is therefore a fact that the expressed juice of mosaic-diseased tobacco plants retained in vitro over five years is still infectious.

(2) STREAK OF TOMATO IN QUEBEC A "DOUBLEVIRUS" DISEASE

Mr. T. C. Vanterpool, working in my laboratory, has been studying "streak or stripe" disease of tomato since 1923. Diseased plants and those artificially inoculated with "streak virus" often tend to outgrow streak symptoms in the upper straggling part of the plant, but they always present mosaic symptoms in those parts. Further, the virus of tomato streak inoculated into tobacco always gave mosaic, and a transfer from that tobacco often reproduced streak in tomato. The possibility of double inoculation was therefore considered, and the following summarized facts cover the work done this season in both greenhouse and field.

Healthy tomato plants inoculated with a mixture of viruses from mosaic-diseased tomato and potato, or tobacco and potato, develop streak in about fourteen days. Mosaic-diseased tomato plants inoculated with virus from mosaic-diseased potato develop streak. Virus from diseased potato gave rise to doubtful mosaic in healthy tomato. Juice from a tobacco plant showing mosaic after inoculation with tomato and potato mixed virus developed streak when inoculated into healthy tomato.

Combinations of bean mosaic and raspberry mosaic viruses with tomato mosaic virus gave negative results.

From the above results it may reasonably be concluded that in Quebec streak or stripe of tomato is not a disease caused by B. lathyri but is a disease resulting from double inoculation, i.e., with virus of potato mosaic and tomato mosaic (tobacco mosaic in this case being considered the same as tomato mosaic). Further work may show that other host plants function as potato, and more work is required to determine the proportions of the two juices necessary to develop streak of tomato.

DEPARTMENT OF BOTANY, MACDONALD COLLEGE, QUEBEC, CANADA

B. T. DICKSON

SEX CHANGES IN BIRDS

IN Science News Service, as printed in your issue of SCIENCE, March 6, 1925, appears an article relating to the changing of sex in pigeons. The observations of Dr. Oscar Riddle, of Carnegie Institution of Wash