integrates any group (0-399)

This new all-electronic MIodel 522 Spectrum Resolver/Integrator may be used directlywith TMC -400 Series" pulse analyzers to perform resolving and integration functionswithout the necessity of intermediate tape recording equipment.As a Resolver the Model 522 takes information directly from any selected quarter orhalf of the analyzer memory and either adds it to or subtracts it from the data stored inan adjacent quarter or half of the memory. It is possible to remove individual compo-nents of a spectrum and leave only the desired elements by adding or subtracting100%, 10%, 1% or 0.1% increments of reference spectra. The operator has precisecontrol of the resolving process, and has an accurate visual record of the exact per-centage removed.As an Integrator, the Model 522 integrates memory-stored information within anyband of channels from 0 to 399 in onie operation. Two modes of integration are available:

NORMAL mode sums the counts in the preselected band and stores thetotal in the last channel.SUBTOTAL mode adds each channel count to the previous one to providea running subtotal.

With every operation, results are displayed on the analyzer scope and may be printed,recorded or punched out by the readout method of your choice.Case design of the Model 522 Resolver/Integrator is identical to that of the com-patible -400 Series" fully-portable, 400-channel Pulse Height Analyzers.

SPECIFICATIONSResolving Rate .......... 0.5 sec. for one add or subtract operation per 100 channels% Resolved...... . ......100%,10%, 1% or 0.1%Integration Rate. 0.5% sec. per quarter memoryChannel band. Continuous 1 - 400 channelsIntegrating Modes .Normal, SubtotalBlanking .... Only channels to be integrated are visible on Analyzers CRT display

Size..-..85/s" w. x 10"/4 h. x 21" d., 28 lbs. (approx.)

TYPICAL DISPLAYS

Step 1 Step 2

RESOLVING

NORMAL INTEGRATION MODE

SUBTOTAL INTEGRATION MODE

TMC is the original designer/producer of transistor-ized multi-channel analyzers. Today, TMC instrumenta-tion is delivered to every nation in the free world foruse in the most advanced laboratories known to man.For full specifications, information, consultation,please write or phone your nearest Sales Office orfactory direct ... North Haven CE 9-2501.

726

TECHNICAL MEASUREMENT CORPORATION441 WASHINGTON AVENUE, NORTH HAVEN, CONN., U.S.A.

.Sales Offices in all Principal Cities of the Free World

EUROPE: TECHNICAL MEASUREMENT CORPORATION, GmbH, Frankfurt/Main, GermanyFAR EAST: NICHIMEN CO., LTD., Tokyo, Japan

SCIENCE, VOL. 139

university's skin research center has abroad biological orientation, and eachyear the center conducts a well-organ-ized symposium at which the results ofits own work and that carried on atsimilar centers is presented informally.The current monograph 'contains

basic information on the structuraland ultrastructural detail of eccrinesweat glands, on their role in thermo-regulation, and on their biochemicaland pharmacological reactions. Theeditors have attempted to relate theform and function of these skin ap-pendages, particularly in the light ofnewer knowledge of their ducts and ofthe mechanisms by which injuries tothem are repaired.

LEON H. WARRENMichigan Department of Health,Lansing

Physical Chemistry

In Calculations in Physical Chemistry(Wiley, New York, 1962. 217 pp.$4.50), the authors, B. W. V. Hawesand N. H. Davies, present approxi-mately 400 problems that require nu-merical solutions. The topics covered,which range from nuclear chemistry,kinetic theory, phase rule, and thermo-dynamics to chemical kinetics andmolecular structure, represent the ma-terial in a rigorous 1-year course inphysical chemistry. Many of the prob-lems appear to have been written forthis book or for classes taught by theauthors, others have been taken fromthe examination papers of students at anumber of British universities, and anumber have been taken from workpublished in the chemical literature,though in some areas-for example,the solid state-all, or almost all, havebeen designed specifically for class use.The subject matter covered is well

within the scope of the typical under-graduate course taught in this country,though most of the problems requireindependent thinking, not the meremechanical substitution of numbers inequations. The book is reasonably self-contained: for many of the problemsthe authors provide notes and hints onhow to proceed with the numerical so-lutions, and in most cases any neededequations are provided. Logarithmtables and answers for all of the prob-lems are provided. It is perhaps un-fortunate that a number of solutionsare not worked out in detail in eachchapter, since such examples would22 FEBRUARY 1963

provide the small amount of encourage-ment needed to persuade many studentsto take the plunge on their own. Thisis, however, a small fault.

This is a useful addition to the well-known books by Wolfenden and byGuggenheim and Prue and should behelpful in teaching undergraduateclasses in physical chemistry. The bookis well printed and reasonably priced.

ERIC HUTCHINSONDepartment of Chemistry,Stanford University

High School Mathematics

Geometric Transformations by I. M.Yaglom, translated from the Russian byAllen Shields (Random House, NewYork, 1962. 140 pp. Paper, $1.95), is adelightful book that can be read by abright high school student with a back-ground in geometry. It is one of thevolumes in the School MathematicsStudy Group series, which are intended"to make some important mathematicalideas interesting and understandable toa large audience of high school studentsand laymen."

Although Euclidean geometry ischaracterized as the study of thoseproperties of figures that are left un-changed by distance-preserving trans-formations (that is, isometries), onedoes not usually learn about thesetransformations until he studies coordi-nate geometry. Yaglom shows howmuch the isometries can contribute tothe study of geometry without the aidof coordinates. Coordinates are men-tioned only in a footnote as a means ofclarifying the meaning of distance.The book contains a substantial list

of problems that can be solved withthe aid of geometric transformations.The problems are challenging, andmany of them contain results that areunexpected. (Solutions are given atthe end of the book.) If the reader isdissatisfied with the standard of rigorat certain points, he should be able tofurnish the additional details of proofhimself. The author has omitted thesedetails in order to avoid a ponderousstyle. The reader is given a new per-spective of the meaning of geometryand the meaning of congruence. Thetranslation is sufficiently smooth so thatone is unaware that the volume is atranslation.

ARTHUR H. COPELANDDepartment of Mathematics,University of Michigan

New Books

General

Administering the National DefenseEducation Act. The Economics and Poli-tics of Public Education, No. 8. Sidney C.Sufrin. Syracuse Univ. Press, Syracuse,N.Y., 1963. 86 pp. Paper, $1.75.Aus Jahrmillionen. Tiere der Vorzeit.

Arno Hermann Muller and Helmut Zim-merman. Fischer, Jena, Germany, 1962.417 pp. Illus. DM. 30.Book Publishing in the U.S.S.R. Report

of the delegation of United States bookpublishers visiting the U.S.S.R., August-September 1962. Curtis G. Benjamin et al.American Book Publishers Council, NewYork, 1963. 118 pp. Paper.

Cost and Quality in Public Education.The Economics and Politics of PublicEducation, No. 5. Harold F. Clark. Syra-cuse Univ. Press, Syracuse, N.Y., 1963.64 pp. Paper, $1.75.

Exploring the Universe. AmericanFoundation for Continuing Education.Louise B. Young, Ed. McGraw-Hill, NewYork, 1963. 487 pp. Illus. $6.95.

Fourcroy. Chemist and revolutionary,1755-1809. W. A. Smeaton. Heffer, Cam-bridge, England, 1962. 312 pp. Illus. $6.The General Practitioner. A study of

medical education and practice in Ontarioand Nova Scotia. Kenneth F. Clute. Univ.of Toronto Press, Toronto, Canada, 1963.582 pp. $12.The Genetic Code. Isaac Asimov. Orion

Press, New York, 1962. 187 pp. Illus.$3.95.

Higher Education and the Federal Gov-ernment. Charles G. Dobbins, Ed. Amer-ican Council on Education, Washington,D.C., 1963. 136 pp. Paper, $2. Nine pa-pers presented at ACE's 45th annualmeeting, Chicago, Ill. (1962).The Man Who Found Out Why. The

story of Gregor Mendel. Gary Webster.Hawthorn, New York, 1963. 188 pp. Illus.$2.95 (juvenile).

Missions dans le Pacifique. Recifs coral-liens, huitres perlieres. Gilbert Ranson.Lechevalier, Paris, 1962. 108 pp. Illus.NF. 20.The Myth of Simplicity. Problems of

scientific philosophy. Mario Bunge. Pren-tice-Hall, Englewood Cliffs, N.J., 1963.253 pp. Illus. Trade ed., $7.95; text ed.,$5.95.New Sources of Energy and Energy

Development. Report on the U.N. con-ference on new sources of energy, Rome(1961). United Nations, New York, 1962.71 pp. Paper, 750.The Practice of Silviculture. David

Martyn Smith. Wiley, New York, ed. 7,1962. 586 pp. Illus. $10.95.The Restless Atmosphere. F. K. Hare.

Harper and Row, New York, 1963 (©1953). 192 pp. Illus. Paper, $1.35.

Satellites, Rockets, and Outer Space.Willy Ley. New American Library, NewYork, revised ed., 1962. 128 pp. Illus.Paper, 60¢.

Science for the Non-Scientist. A. R.Patton. Burgess, Minneapolis, Minn., 1962.130 pp. Illus. Paper, $2.50.The Scientific Life. Theodore Berland.

Coward-McCann, New York, 1962. 316pp. $5.75.

749

ANNOUNCING ANOTHER F I R S T

What G-100 Is SEPHADEX G-100, like itswell-known predecessors in the SEPHADEX series ofdextran gels,* is produced by cross-linking dextran chainswith random ether bonds between glucose residues in thepolysaccharide chains. Highly stable mechanically andchemically, G-100 upon swelling produces three-dimen-sional networks bevoid of ionic groups. Prepared in beadform, G-100 offers very low flow resistance, thus per-mitting the use of fine particles for good resolution ofsepa-ration.

What G-100 Does This new SEPHADEXtype is an important extension of the gel filtration methodinto the field of macromolecular fractionation, makingpossible the separation of substances with molecularweights smaller than about 100,000. Like the otherSEPHADEX types,* G-100 acts as a molecular sieve,and molecules of larger dimension do not penetrate thematrices of the swollen gel.

The accompanying chart shows a separation of pancreaticenzymes. Powdered swine pancreas was extracted witha 0.05 M acetate buffer pH 5.3 containing 0.005 M cal-cium acetate. A 3 ml. sample was introduced in a 2 x 37cm. (1 17 ml.) column packed with SEPHADEX G-100.

U I

PHARMACIALEADING IN DEXTRAN

CHEMISTRY

For completeinformation aboutGel Filtration and alltypes of SEPHADEX,please fill in therequest coupon andsend it to us withyour letterhead.(Inquiries outside theWestern Hemisphereshould be directed toPHARMACIA, Uppsala,Sweden.)

A Typical Separatlon with SbIEHAL)tE t-IUUSample: 3 ml. of an extract of powdered swine pancreas in0.05 M acetate buffer pH 5.3 containing 0.005 M calciumacetate.Column size: 117 ml. (2 x 37 cm.).Elution: 0.05 M acetate buffer pH 5.3 containing 0.005 M cal-cium acetate.

What G-100 Promises Clearly, theSEPHADEX G-100 field is one of enormous interest,especially for biochemical and medical research. G-100now makes possible the fractionation and purificationof enzymes, polysaccharides, nucleic acids, peptide hor-mones, and proteins on preparative scale. And it super-sedes the earlier, more complicated, and time-consumingmethods that were previously required.*Also available: SEPHADEX G-25, G-50, and G-75.

n~ PHARMACIA FINE CHEMICALS, INC. S| II!)Department F, 501 Fifth Avenue, New York 17, New YorkPlease send the following:Em G-100 "SEPHADEX IN GEL GEL FILTRATIONI BROCHURE FLTRATION" BROCHURE ABSTRACTS

Name

Company

Address

L _ _ _ _ _ _ _ _ _ _ __._

22 FEBRUARY 1963

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