SCIENCE~~~~~~~~~~---A

NEW SERIES FRIDAY OCTOBER 27 1939 SuBSCRIPTION, $6.00VOL. 90, No. 2339 R O SINGLE COPIES, .15

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PORCEELAINModern laboratory technique re-quires porcelain ware in which highmechanical strength is combinedwith maximum thermal and chem-ical resistance. Of equal importanceis the character of the workmanshipand the glazing. These essential re-quirements are characteristics of"COORS" brand porcelain ware.

Coors Porcelain Ware is subjectedto two firings in modern continuoustunnel kilns which insure uniform-ity. Close control is given to allbranches of production, from themining of the raw materials to theultimate inspection of the finishedware.

Everything entering into the CoorsPorcelain body and glazes is of thehighest quality, consequently Coorsmanufactures only one grade ofporcelain ware-the best.

NEW CATALOG, NO. 1939SENT ON REQUEST

EIMER &AMEND205-223 THIRD AVENUE, NEW YORK

Fn1ter-ed aS 8eeond-e7las matter Jully 18, 1923, at the Po8t Office at Ijanea8ter, Pa., under the Act of March 8, 1879.

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2 SCIENCE-ADVERTISEMENTS VOL. 90, No. 2339~~~~~~~~~

CARNEGIE INSTITUTION OFWASHINGTON

Is a research organization working in manyfelds. Its monographic publications are placedin the principal libraries of the world. Copiescan be purchased at nominal cost.

These publicationsfollowing fields:

ARCHAOLOGYANTHROPOLOGYASTRONOMYBIOLOGYBOTANYCHEMISTRYECOLOGYECONOMICSEMBRYOLOGYGENETICSGEOLOGY

comprise studies in the

HISTORYLITERATUREMATHEMATICSNUTRITIONPALEONTOLOGYPALEOGRAPHYPHILOLOGYPHYSICSTERRESTRIALMAGNETISM

ZOOLOGY

Descriptiv6e Iwt with prices may be obtainedby addressing

CARNEGIE INSTITUTION ef WASHINGTONWASHINGTON, D. C., U.S.A.

Hugh Minler's

History and ScienceA Study of the Relation of Historical

and Theoretical Knowledge

An important contribution to currentphilosophical controversy. The auth-or's theme is that theory and historyare everywhere two complementary ap-proaches to natural knowledge and thateach is -equally of general application.

Price, cloth, $2.00

Order through your bookseller,or direct from

THEUNIVERSITY OF CALIFORNIA PRESS

BERKELEY :: CALIFORNIA

Volume 15 1940

STAIN TECHNOLOGYA JOURNAL FOR MICROTECHNIC

QUARTERLY

CONTENTSORIGINAL ARTICLES

Microscopic TechnicNature and Uses of Biological StainsNew Staining Methods

LABORATORY HINTS FROM THELITERATURE

Published by

BIOTECH PUBLICATIONSBox 299, Geneva, N. Y.

STAIN TECHNOLOGY

is the official organ of the

COMMISSION ON STANDARDIZATION OF

BIOLOGICAL STAINS

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BACK NUMBERS AVAILABLE ATFOLLOWING RATES:

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$2.25 for other volumes

$33.00 for vols. 1-14 (if cashaccompanies the order)

Note: Biotech Publications was formerly theBook Service of the Biological Stain Commission,which has been publishing this journal for 14 years.

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2 SCIENCE-ADVERTISEMENTS VOL. 90, NO. 2339

OCTOBER 27, 1939 SCIENCE-ADVERTISEMENTS 3

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Spencer Quebec Colony CounterGreater accuracy, greater efficiency and increased comfort are

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SCIENCE-ADVERTISEMENTS 3OCTOBERW 27, 1939

4 CEC-AV TIEETVO.9,N.23

Nos. 3794A to 37981-Grades "A" available in sizes2:5 x 30 mm, 25 x .50 mm, 100 x 100 snm. Grade "B"

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Grade "A" (14,440 lines) will separate the sodium "D"lines up to eight times the width of the line when usedwith a lens of 2.75 m focal length.Grade "A" (4,800 lines) will separate "D" lines underthe same conditions to two or three times the line width.Grade "B" less perfect than grade "A" but still capableof separating the D lines.All replicas except the elementary grade are supplied insubstantial plush-lined cases.

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VOL. 90, NO. 23394 SCIENCE-ADVERTISEMENTS

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.OCToBzR 27, 1939 SCIENCE-ADVERTISEMENTS -5

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6 SCIENCE-ADVERTISEMENTS VOL. 90, No. 2339

B&L ACCESSORIES ADD TO YOURI A .BALOPTICON'S ADAPTABILITY

THE B&L FILM PROJEC-TOR ATTACHMENT con-verts lantern slide balopti-con into stil film projector.

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VOL. 90, No. 2339SCIENCE-ADVERTISEMENTS6

VOL. 90, No. 2339

of limited quantity is to be analyzed, the apparatuscan be clamped shut at the proper moment. A tuningfork whose frequency of vibration per second is 512 isplaced over the upper end of the tube. By striking thetuning fork and raising and lowering the column ofwater, points of resonance (accentuation of the humof the tuning fork) are found. The distance betweentwo adjacent points of resonance is half of one wave-length. This distance times two, multiplied by 512(the frequency of vibration of the tuning fork) equalsthe velocity of sound per second. A small correction,which is rarely significant, is made in the velocityfor variation in laboratory temperature (Table 1);

TABLE 1CORRECTION OF VELOCITY OW SOUND FOR VARIATIONS OF

TEMPERATURE FROM 240 C

Velocity ofsound, metersper second to 650 750 850 900 and over

1' C. equals(meters persecond) ±0.5 ±0.14 ±0.3 special correc-

tions (see be-

Add or subtract low)with rise intemperature subtract subtract add add

Special corrections for velocities of 900 meters per second andover:

180 C. 19 20 21 22 23 24 25 26 27 28 29 30-4.1 -3.6 -3.0 -2.4 -1.7 -0.9 0.0 +1.1 +2.2 +3.5 +5.0 +6.7 +8.5

"-" indicates substraction for correction to 240 C.; "+"Indicates addition.

changes in the temperature affect the velocity bychanging the density of the gases and by changing theamount of water vapor in the mixture.The formula for the velocity of sound in a gas is

V- IYPd'

whereV=velocity of sound in centimeters per second;y = Cp/Cv = ratio of specific heat at constant pressure to

that at constant volume (y for oxygen is1.401; for nitrogen it is 1.404; for helium itis 1.66);

P = pressure in dynes per square centimeter; andd = weight of gas in grams per cubic centimeter.

A chart (Fig. 2) has been constructed on the basisof computation of the theoretical velocity of soundfor many different mixtures of helium, oxygen andnitrogen. In using the chart one can read horizontallyfrom the experimentally determined velocity of sound,corrected for temperature, to the determined percent-age of oxygen, which may have to be interpolated,thence vertically to the percentages of helium andnitrogen in that portion of the gas remaining afterdeducting the oxygen. In practice, a large-sizedreplica of Fig. 2 on graph paper is used.No attempt has been made to control all the sources

of error, most of which are small and may offset oneanother. It is possible to determine the velocity ofsound with our apparatus with an accuracy of ap-

0 10 20 30 40 S0 60 X10 80 900 oo HQlium100 90 80 70 60 S0 40 30 £0 10 ONitrogmVolumQ % in (100-% 2O)

FIG. 2. Chart showing the velocity of sound at 240 C.in mixtures of helium, oxygen and nitrogen, saturatedwith water vapor.

proximately ± 0.5 per cent. (range of variability) andto determine the percentages of helium and nitrogen inthe whole mixture with an accuracy of approximately± 1.0 per cent. (range of variability). The apparatusand method are intended for practical use in medicineor industry where this degree of accuracy is satisfac-tory. The apparatus is inexpensive, mobile, simpleand easy to use.

WILLIAM B. DUBLINWALTER M. BOOTHBYMARViIN M. D. WILLIMS

THE MAYO CLINIC

BOOKS RECEIVEDARNOW, L. EARLE. An Introduction to Physiologicaland Pathological Chemistry. Pp. 555. 143 figures.Mosby. $3.50.

CHARLES, BROTHER H. Biology. Pp. viii + 408. Illus-trated. Bruce. $1.72.

EALES, N. B. The Littoral Fauna of Great Britain; aHandbook for Collectors. Pp. xvi + 301. 24 plates.Cambridge University Press, Macmillan. $3.50.

EDDY, SAMUEL, CLARENCE P. OLIVER and JOHN P. TURNER.Guide to the Study of the Anatomy of the Shark, theNecturus and the Cat. Pp. vii + 100. 15 figures.Wiley. $1.50.

PARKER, JOHN B. and JOHN J. CLARKE. An Introduc-tion to Animal Biology. Pp. 503. 163 figures. Mosby.$3.75.

WHITEFORD, G. H. and R. G. COFFIN. Essentials of Col-lege Chemistry. Second edition. Pp. 534. Illus-trated. Mosby.

400 SCIENCE

OCOE 7 93 CEC-DVRIEET

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THEDEVELOPMENT

OF THE MINKOWSKIGEOMETRY OF

NUMBERSBy Harris Hancock

Professor Emeritus of Mathematics, University of Cincinnati

In this new volume, a sequel to his "Foundationsof the Theory of Algebraic Numbers," ProfessorHancock again makes an important and originalcontribution to mathematics. He uses the the-orems of Minkowski to develop and clarify the re-lationships between the number theory, intuitivegeometry, and the theory of functions, and to showhow studies in algebra, geometry, and arithmeticare harmoniously interrelated. By thus making useof the concepts of geometry he is able to broadenthe substructures of the generalized realms that arefounded on algebra, numbers, and geometry; andascertains further the teleological nature of suchrealms. "Minkowski came to his theorems throughspecial intuitions," writes the author in a Preface."Due to the limitations of a manifold in three di-mensions he presented his theory in a purely analy-tical manner. Thus while he was able to treatmanifolds in any order, his work is far more diffi-cult of comprehension than if he had first derivedhis results in a two or three dimensional geometrywith illustrative figures, and then presented thegeneral theory analytically with the use of expres-sions indicative of geometric concepts. From thisstandpoint I have given the entire theory."

864 pages

$12.00

A SHORTHISTORY OF

SCIENCEBy W. T. Sedgwick

Late Professor and Head of the Department of Biology, Masse-chusetts Institute of Technology

and H. W. TylerLate Professor and Head of the Department of Mathematics,Massachusetts Institute of Technology

Revised by H. W. Tyler and R. P. BigelowProfessor Emeritus of Zoology, Massachusetts Institute ofTechnology

The Sedgwick and Tyler History of Science hasbeen for years the standard college text for orien-tation courses in the sciences. The present exten-

sive and thorough revision brings the book up to

date. It now contains the complete story of sci-entific development from the number systems andearly astronomical notions of ancient Islam to our

twentieth century conceptions of the behavior ofatoms and hormones. Throughout the book theprogress of scientific methods as well as of concepts

is traced, and an equitable treatment is given to allbranches of science, both biological and physical.For anyone seeking a clearly understandable, wellbalanced knowledge of the historical backgroundof modern science, this book is a preeminentlysatisfactory answer.

To be ready in November. Illustrated.

c.510 pages. $3.75 (probable).

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SCIENCE-ADVERTISEMENTS 7OCTOiBER 27, 1939

OCTOBER 27, 1939 SOIENOE-AIJVERTISEMENTS 9

McGraw-Hill Books in PhotographyTHE PHOTOGRAPHIC PROCESS

By JULIAN ELUs MACK, University of Wisconsin, and MIIES J. MARTIN, Milwaukee Exten-sion Center, University of Wisconsin. 586 pages, 7 x 9A, illustrated. $5.00

Here is a unified, comprehensive treatment of photography, presented simply enough for the student who is nottrained in chemistry, yet with sufficient scope and scientific rigor to justify its use in a course in photographyat the college level. The manual section of the book gives working directions for a variety of specialized opera-tions, including lens testing, shutter testing, the use of polarizing discs, sensitometry, color photography, etc.

HANDBOOK OF PHOTOGRAPHYBy KEITH HENNEY and BEVERLY DUDLEY, Editors, Photo Technique and Electronics. 1000pages. 6 x 9, illustrated. $7.50

Intended to supplement the many volumes available covering elementary, specialized, or purely artistic phases ofthe subject, this book presents a comprehensive, authoritative treatise on the technique of the photographicprocess and the scientific basis underlying photography and its applications.

COLOR PHOTOGRAPHY FOR THE AMATEURBY KEITH HENNEY. Whittlesey House Publication. 281 pages, 5i x 8, illustrated. $3.50

In this book the author provides a practical manual of field and laboratory procedures in color photography. Allphases of the subject are described in detail, and complete practical information is given on lUms, filters, andsupplies; negatives and exposures; transparencies and paper prints; dye and pigment processes, etc.

New Ways in Photography. Ideas for the AmateurBy JACOB DESCHIN, Camera Editor, Scientific American. Whittlesey House Publication.307 pages, 5i x 8, illustrated. $2.75

Making Pictures with the Miniature Camera.A Working Manual

By JACOB DESCHIN. Whittlesey House Publication. 251 pages, 54 x 8, illustrated. $3.00

Finding New Subjects for Your CameraBy JACOB DESCHIN. Whittlesey House Publication. 240 pages, 5i x 8, illustrated. $2.50

Lighting Ideas in Photography.A Book of Methods for the Amateur

By WILLIAM HERRSCHAFT, Illuminating Engineer, and JACOB DESCHIN. Whittlesey HousePublication. 278 pages, 6 x 9, illustrated. $2.75

Send for copues on approval

McGRAW-HILL BOOK COMPANY, INC.330 West 42nd Street, New York, N. Y. Aldwych House, London, W.C.2

OCTOBBM 27, 1939 SCIENCE-ADVERTISEMENTS 9