SCIENCE----VOI. 90 No. 2329 FRIDAY, AUGUST 18, 1939 SINGLE COPIES, .15

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Review of the History and Philosophyof Science and of the History of

Learning and Culture,edited by

GEORGE SARTON, D.Sc.HARVARD LIBRARY 185, Cambridge, Mass.

Isis may be obtained from any Bookseller at theprice of 6 dollars per volume illustrated. Membersof the History of Science Society receive each yearat least one volume of about 600 pp. free of charge.Annual dues, 5 dollars. Corresponding Secretary,Dr. Henry R. Viets, 8 The Fenway, Boston, Mass.

Isis is the foremost journal on the history ofscience published in the world to-day. It containsarticles, reviews, notes, queries, and elaborate criti-cal bibliographies of the history and philosophy ofscience. Vols. 30 and 31 will be published in 1939.

Writers of books and papers on the history ofscience are asked to send a copy as promptly aspossible to the Editor of Isis in order that theymay be registered in the Critical bibliography.This is the best way of obtaining for their workits certain incorporation into the literature of thesubject.

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SCIENCE-ADVERTISEMENTS 0VOL. 901 No. 23292

AUGUST 18, 1939 SCIENCE-ADVERTISEMENTS 3

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SCIENCE-ADVERTISEMENTS VOL. 90, NO. 23296

AuGUST 18, 1939

ican Soeiety of Mechanical Engineers, serving for twoterms; three times a vice-president of the American Asso-ciation for the Advancement of Science, and a member ofthe American Society of Civil Engineers and of numerousother technical and academic organizations in this countryand abroad. He also served on several important stateand federal commissions.

Dr. Thurston was considered an authority on materialsof construction, steam engines and boilers, and the historyof engineering, as well as on the philosophy of education.His most widely known work, "A History of the Growthof the Steam Engine," published originally in 1878, isscheduled for republication this year as part of the cele-bration of the eentennial of his birth.

Training engineers to meet the problems of the futurewas a subject of perennial interest to Dr. Thurston and.will be the theme of the Anniversary Convocation.Thurston, the pioneer, proclaimed values and enunciatedprinciples that have a bearing to-day, and the spirit ofThurston counsels boldness in grasping the immense oppor-tunities of to-morrow.

RECENT DEATHS AND MEMORIALSDR. LEWIS D. ROBERTS, professor of physical chem-

istry at the University of Southern California, died bysuicide on August 3. He was in his fifty-sixth year.

DR. CLYDE MASON SHAW, professor emeritus of theCollege of Pharmacy at the University of Illinois,Chicago, died on August 5, at the age of seventy-oneyears.

DR. COOPER CURTICE, who retired as veternarian atthe Bureau of Animal Industry of the U. S. Depart-ment of Agriculture in 1930, known for his work in theeradication of cattle ticks and cattle-tick fever, diedon August 8, at the age of eighty-three years.

Nature reports the death on July 28 of ProfessorR. W. Reid, emeritus regius professor of anatomy inthe University of Aberdeen; and of Scoresby Rout-ledge, known for his investigations among the Akikuyuof East Africa and of the archeology and ethnologyof Easter Island, on July 31, in his eightieth year.

ACCORDING to Nature a teak memorial seat to the lateSir William Perkin, the chemist, is to be unveiled anddedicated to the public at Sudbury, Middlesex, onAugust 12. The memorial will be outside a recreationground, and opposite the site where Sir William'shouse and laboratory stood. The cost of the memorialhas been met by public subscription.

SCIENTIFIC NOTES AND NEWSDR. ROBERT A. MILIKA.N, of the California Insti-

tute of Technology, accompanied by Dr. H. VictorNeher and Dr. W. H. Pickering, sailed for Australiaon August 16. They will engage in cosmic ray re-

search in Australia, Tasmania, the East Indies, Indiaand Egypt, returning in February, 1940.

THE Royal College of Physicians has made the fol-lowing awards: the Baly Gold Medal to Dr. C. H.Best, professor of physiology in the University ofToronto, for his physiological researches; the MoxonGold Medal to Sir Arthur Hurst, senior physician toGuy's Hospital, for his researches and observations inclinical medicine; the Weber-Parkes Medal and Prizeto Sir Pendrill Varrier-Jones, founder and medicaldirector of the Papworth Village Settlement, for hiswork on tuberculosis.

THE gold medal of the Royal Agricultural Societyof England has been awarded to Sir George Stapledon,professor of agricultural botany at the University Col-lege of Wales at Aberystwyth and director of theWelsh Plant Breeding Station, "for his distinguishedservices to agriculture."Tim prize of the Senckenberg Foundation of the

value of about 4,000 marks, which was established ahundred and seventy-five years ago, was awarded on

the occasion of the twenty-fifth anniversary of theuniversity at Frankfurt-a/M, to Dr. Ernst Ruskafor his-work with the electron mieroscope. The prize

is awarded every three years to a German investigatorfor contributions to the advancement of medicine orscience.THE Journal of the American Medical Association

reports that at the annual meeting of the MinnesotaState Medical Association it was voted to present thedistinguished service medal and scroll, awarded tomembers for special contributions to the work of theassociation, to the late Drs. William J. Mayo andCharles H. Mayo. Their photographs will be hung inthe Medical School of the University of Minnesota.

DR. GEORGE H. FANCHER, professor of petroleumengineering at the University of Texas, has been electeda fellow of the International Institute of Petroleum,which has its headquarters in London.THE University of Edinburgh has conferred the

doctorate of laws on Dr. Francis H. A. Marshall, fellowof Christ's College, Cambridge, and reader in agricul-tural physiology in the University of Cambridge, inrecognition of his work in the physiology of repro.duction.PROFESSOR LuIGo D'AMATo, director of the Medical

Clinic of the University of Naples, has been made asenator of Italy.

DR. LAIGNEL-LAVASTINE, professor of the history ofmedicine at the University of Paris, has been electedpresident of the International Society of the Historyof Medicine.

SCIENCE 153

VOL. 90, No. 2329

clearance was studied in a series of tubes in which thedistance between the walls was varied from 1.3 mm to22.0 mm. The gas separation (ratio of ammonia tomethane) rose sharply with increasing wall clearanceto a rather broad maximum at 7 mm. The effect ofgas pressure was investigated from 11 to 60 cm of Hgfor the different tubes. The 7 mm tube gave a maxi-mum gas separation of 27 per cent. at 20 cm pressure.The pressure however is not critical nor is the optimumpressure the same for all gas mixtures. In these teststhe temperature difference between the walls was 3500and the average temperature of the gas close to 150°.By varying the power input it was found that the finalgas separation increased with the temperature differ-ence between the walls. The rate of separation wasinvestigated for a wall clearance of 7 mm and a tem-perature difference of 3500. The separation rose to 90per cent. of its final value in 15 minutes. The absoluterate at which gas could be removed without decreasingthe separation factor was not determined with ac-curacy; it was observed, however, that I cc of gas(N. T. P.) could be removed every 15 minutes withoutinfluencing the percentage separation. This speed sug-gests that a continuous flow method of operation shouldbe feasible.A number of gas mixtures have been studied in addi-

tion to the one mentioned above. The operation of thetube can be shown in a striking manner with a uniform50-50 mixture of helium and bromine. In the courseof a few minutes the bromine completely disappearsfrom the top of the tube and becomes concentrated atthe bottom. The separation of isotopes is easily demon-strated with HCl, in which gas the ratio of Cl35 to Cl37was changed at a pressure of 20 cm from 3.2, its normalvalue, to 2.8 in a few minutes. The optimum condi-tions of operation depend, of course, on the nature ofthe gas. The results obtained with. different gas mix-tures lead to the conclusion that the separation dependsprimarily on the difference in mass of the two com-ponents divided by their sum.

Experiments have been performed which throw addi-tional light on the mechanism of operation. When theentire tube was inclined 13° from the vertical theseparation was decreased from 27 per cent. to 5 percent. In another apparatus a series of corrugationswas placed every 3 cm along the inner tube in such amanner that any gas moving along the heated wallwould be deflected into the intervening space. In a50-50 methane-ammonia mixture the average tempera-ture of the gas was reduced about 150 and the finalseparation enhanced about 4 per cent. The design ofthe tube also appears to have a marked effect on thegas separation. A tube was built along the linesdescribed by Clusius and Dickel with a heated tungstenwire extending down the center and a 7 mm clearance.After a run of several hours a smaller final separation

of the chlorine isotope was observed with an 800°difference in temperature than was obtained in 15 min-utes with the concentric glass tubes for a 3500 differ-ence in temperature. A 3500 difference in temperaturegave only a negligible separation. A similar tube witha 4 mm platinum ribbon down the center failed toshow an appreciable separation. It is evident thatseparation is augmented by symmetry of the two sur-faces. An all-glass apparatus in which the outer wallwas heated and the inner cooled gave a separationvalue only slightly lower than when the inner wall washeated; the average temperature of the gas, however,was materially higher.The rate of mixing of the separated gases has been

investigated for various tubes. The results show thatthe rate of back diffusion increases with wall clearanceand becomes very rapid for outside tubes of largerdiameter.Reviewing the above results as a whole, it is evident

that conditions involving both wall symmetry and cor-rugations enhance swirl definition and thereby enhanceseparation. On the other hand, separation is mate-rially lower in straight wire or ribbon-centered tubesas well as in tubes having small wall clearances inwhich swirls are either poorly defined or impossible.It appears that the mechanism of separation is differ-ent in the two cases. Under conditions where swirls arewell defined the separation results from the combinedaction of initial and thermal diffusion within the swirls.In wire-centered tubes or glass tubes with small wallclearances where the swirls are poorly defined, themechanism may involve thermal diffusion and anoverall convection current.We wish to thank Mr. Leonardo Testa, the glass-

blower, for constructing the large number of tubes usedin these experiments.

ARTHUR BRAMLEYA. ]KEITH BREWER

BUREAU OF CHEMISTRY AND SOILS,U. S. DEPARTMENT O0 AGRICULTURE

BOOKS RECEIVEDCONWAY, EDWARD J. Micro-diffusion Analysis and Volu.

metric Error. Pp. xiii + 306. 49 figures. Crosby,Lockwood, London. 25/-.

CUMMINGS, ALEX., CHARLES, and SNYDER A. KAY. AText-book of Quantitative Chemical Analysis. Pp.xv+496. 85 figures. Van Nostrand. $5.00.

Meeting the Needs of the Mentally Retarded. BulletinNo. 420 of the Department of Public Instruction, Com-monwealth of Pennsylvania. Pp. 158. Illustrated.The Department, Harrisburg.

MILLS, CLARENCE A. Medical Climatology. Pp. vii +296. Illustrated. Charles C Thomas. $4.50.

POPE, CLIFFORD H. Turtles of the United States andCanada. Pp. xviii + 342 + v. 99 plates. Knopf.$3.75.

WOLF, RALPH F. India Rubber Man; The Story ofCharles Goodyear. Pp. 291. Illustrated. CaxtonPrinters, Caldwell, Idaho. $3.00.

166 SCIENCE

AUGUST 18, 1939 SCIENCE-ADVERTISEMENTS

Praise for an Outstanding New Text

Fundamental Principlesof

BacteriologyBy A. J. SALLE

University of California

659 pages, 6 x 9, illustrated. $4.00EACHERS have acclaimed this newly published text as one of the most important contributions to thefield of bacteriology that has appeared in recent years.

The following comments are representative:

"I have examined it with considerable interest because of its completeness as a book in general bacteriology.I would like to congratulate Dr. Salle and you on what I consider to be the best textbook that has ever beenpublished on that subject." Professor GEORGE M. LAWSON, University of Virginia"I feel sure that Dr. Salle's book is a distinct contribution to bacteriological texts. It is.full of meat and notthe same old material rehashed in a slightly different fashion."

Professor WILLIAM BURROWS, University of ChicagoThis combined textbook and laboratory manual lays particular stress upon fundamentals, gives explanationsof all phenomena described in the book insofar as it is possible to do so, and emphasizes the importance ofchemistry in an intelligent approach to the subject matter.

The book is intended for students who are beginning the study of bacteriology, and especially for those whoare going to specialize in the subject or in closely related fields.Special Features of the Book:

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-the book covers in detail the following topics, which have received inadequate treatment inmost other texts.

(a) BIOLOGICAL STAINS: A discussion of dyes and staining solutions;(b) BACTERIAL RESPIRATION: A pioneer treatment of this subject;(c) YEASTS AND MOLDS: Profusely mustrated with morphological pictures of the

various organisms;(d) ENZYMES: Detailed classification including the chemical reactions for the action

of enzymes on the specific substrates and the end products formed.-the chapter on Disinfectiou and Disinfectants Includes a detailed discussion of the toxicity

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