simplifiedretrieval ofnoise buriedsignals with

Ithaco's 353Phase-Lock amplifier

* no tuning required* phase and gain not affected by adjust-ment or drift in reference frequency

* adapts automatically to virtually anyreference input

* ultra stable, highly linear detector-nooverload at 1,000: 1 noise to signalratio

* 1.0 Hz to 200 KHz operation

* plug-in construction permits additionof new or specialized features-pre-vents obsolescence

For further information and completespecifications contact:

607 272-7640

4ITHACO INC.413 TAU GHANNOCK BLVD., ITHACA, N.Y. 14850

See us at '69 Physics Show, Booth 177.

New toploading balanceis fast, accurate...yet RUGGED!-Ncss rIhil FIT- toploader (I 60- capacit\, mii'accuracy) iakes laccurate xwe-ihiniig easier aridmoIe oolpir-oft hin es er before.N F W I ANSI thanks to complete digital display

ws ithout the use of opttical projections o sve niers Loecald, no estinmat incNF \V AF bccautse thle one pciCc CoirsltfctLiC n

Of tthe Cs.XCLPtsi c ot-sion1 %.Vcichiri iccbSaistrr hasnio kritfc to cllli) wxcat oi CoIlet (dLust --hnc1ccthelc s no loss in aititacV

NI Vv FASF- thank-s to thc ecc tIr0IitkrLtIllc.(iouiit tc.ttiic, tilt TI-t isProt .tlctcted hxscilsitiWitf. ritic.s - lourltetr1ct Caotirtc or ltniidityat raitions or ctlcectIs oft fol-rlr ttattcr ot- 5 ear.\s 101(on a1s s Irc,c111`, itllt1l rr1:ecdtc triosc fur a

()(I -w ihrtht Irhan-c. tlicri .t dttllctnrcec of. g, in sei It -i1adii o on/1 1 .0 rIg-todlay,

tomiorosr .vne ,riontft.I n st s ecar.N [X-V AsA eCans-.C thc I-I's ITor stun

rIrccfanir ii is tat lesslad cctcd b\ vibraioin thianoptical bat airces. Yrott calnuIS an ET- I in conditionsotfictl hbalaniccs Lart take.NFIW F\AS thank;sto

otLt-of-lCecI acULitIac',FoI- irinot- ch,anges in lexel(if thte FT- , tcr PrOit

|-WRITE FOR FREE BROCHURE.

THE TORSION BALANCE COMPANY Departrnent S. Nain Office and Factrry1CIifton, N. J; Sales Oflites: Birmingham, AIt. C(hica.go, Ill.; Rich;ardson. Tex.; San NMatco, Cal.; RPittsburgh, Pa.; Pi;intns and Otticts in Montrrult, QuL1sh , I ondon. England and W atcrfurd, IrcIand V

140

kinow tof the peculiar- diIffcultiCs ofdisprov ring an erroneous first imlpressioll.The propriety of goernnment cotitrol

oser drug, mralnuflactUrcrs is w idelv de-ateCd iII SUCh joUrnals as ( litiical IhrO-

11t(1( 0/log (1/1(1 /h'Hcrapeutics. Reports otf(tov erinincnt actio(l onl bchallf of' thiecourmun-l1itV s heni thcse controls aic niotobscr vcd bs IanIuLfctirer-s5 are coiini1o0. It Woitld be LsefiSC ll,and fatir. ifsciCntists in societN \s ere allo\\ edl to

judige the informat ion that causCs sIuchacton hcforc coticeditng anv restrictionson cxperinicnital techniqluc. There muiistbe better \sass ot1 comrhating carelessnessor (decelitiotn sWithout ttamipering wxith theticedi to cet tteianss er right.

\. S. I. I O Isi29 Xtuor II(ir 1Bcc Iseitam,ootKel'lf, I' ZIghlotld

Drosophila: Teinder Loving Care

Sonneborn coUld hase flontd no imoreapt aippellation tfor H. J. Mltiller than'( rusader lor humliian betternient" 1I SNov.. p. 772). 1 knew MUller well. AShis studlenlt assist.ant at the L)nivxersitsof Texas,. he andI, together wvith out1-

iN es. spenlt ImuLcIh timile cccling in alndatlroutlnd Austill.

MUller ws as an inteinse hard%svorkillnScientist Msho had little timie tfor Socialfrivolities. In addition hie Nssas .lcite shsad sensitive. allthOLughl heC eailS losthimilselt in his scientific put-rsLits. One olins jobs %sas the care arid feeding, oft)rosopltilor.Vhis ulrla SOuLInd! simplefi, bLitMuller ws as c.acting in his requirements.I remcineiliher onle C hristillas XICaIti()oierio0d in AuLIstin s hlien theI eClt hCrtuLrne.d LfLite cool, so thaM t I \taS afrI'ldII(tlie I)ro.sophlila might sufller in t}IIlile -

heated uni\ersiv t hbtildtli. I catr-ried lieu beS liOLSI r tliceii hiolire in It in nieilpiocket. nid sitice ims metager qulnateirssere nlot too thorou0ls1-l1 hetel'td at illtimievs. I took titcirlto bed itlimeth . I5 as \ eFrs r1o1dI of thteCir sLirslr i a'l.a1nsclin I IOldC liiller of this at the aminions

olt conscieonce iin todcrn timedcinlIe'Icsome ac.trs ago,. ICe c01nsciCltioslsX .iskedtIrCe 'o still oise n soniethino totr-thisI?

NItilier coiitrlihuted a orcat deal to tiliedlevelopnictit of' mv carcer iiiemliciiic.I aim onic ol maux xx1hhslvc oved mitlclhto thiIs mn1.1 ,raithier sii1ll. IIpb sicailsv linta gi-lant in es cry other recspict.

R 'tuNot) \W'IN(iI VO1 reit A tI 1/01t 2 /st Sirt c,t.tvin Pena1 s(/I.8\/Y lvat?i('a 1 80()42

SCtIFN-IC . Vot- l(3

If Not Grades, What Criteria?

Schagrin's letter (15 Nov.), propos-ing a system in which grades would heused internally at the college but nottransmitted to graduate schools, pro-spective employers, and others, andwould be replaced by 'letters of recom-mendation or perhaps evaluation forms."seems at lealst a trifle naive. No sensibleperson attributes more than modest im-portance to grades, but they do havevalue. particularly in some fields ofstudy, in giving some indication ofmastery of the subject maitter-a pointof some interest to institutions withwhich the student might like to becomeassociated. It is obvious that if grades,as now constituted, are not made avail-able, the letter of recommendation willperform exactly the same function underanother nanme.

Schagrin's solution is reminiscent ofthe Midwestern legislator who observedthat railwav ticcidents often involved thelast car on the train, and introduced abill requiring the omission of the lastcar.

R. L. HALLA'JcCormnick & Comnpalnv, Inc.,11350 McCormick Road,.Cock eysville, Mary-illanid 21030

Schagrin's proposed solution to thedifficulties and dilemmas of grading in-terest me greatly and should interestmcany others as well. I would especiallylike to know about the other criteria forselection (besides grades) that he issuggesting for instituitions, such as buLsi-ness. governnment. and the military, touse which have demnionistrahlv higher cor-relations th,an grades with subsequentperformance. On what basis, if not onthe hasis of performance in college, ishe suggesting that letters of recom-mendation he written, and on whatbasis would evaluation forms he ex-ecuted if not on the basis of perform-ance in college? On what basis aregrades assigned if not on the basis ofperformance in college? If grades can-not he trusted to be anything morethan "tokens to purchase favors forgraduates," how can letters of recom-mendlation and the ratings that appearon evaluation forms be trusted to domore?

Is Schagrin suggesting (perish thethought!) that scores on standardizedtests be used as a substitute for gradesfor evaluating students' performance?

WILLIAM H. ANGOFFEducational Testing Service,Princeton, News Jersey 08540

24 JANUARY 1969

1.00U -cis

0.80 -

0.60

0.40

0.20

-0.20- /-0.40-

-0.60 -

-0.80

-1.oo

-1.20

-1.40

- / v-

- ''~ j ci,,- ' t% 2 -

1G 216 18 20 22 24

* f. drd wn bi DLiurrurn

PROVING THEMIRROR-IMAGE

CHARACTERISTICSOF TWO

ASPARTIC-ACIDISOMERS

- (u I-cis u2- Cis)/2

- s- Cis

26 28 30 32Wavenumber 10 3

) >DURRUM3950 Fabian Way, Palo Alto, California 94303. Call (415) 321-6302

Cable: DURRUM, Palo Alto

341

- ol- -1 11, - I. - I-11-1 -.- II - 11- II 1- 1 - I- ''I - "I'll - 11 - 11. 1.

Pr'

Aspartic aci(d, with its three (lonor sites, can form a variety ofhard-to-iden-tify chelate isomers. 'T'he circular-(lichroism p)rofiles(drawin here, plotte(1 from (lata g,atherecI b)v a Durrum-Jasco CDrecor(ler, are typical of the molecular detective work' that can1b)e achieved with this versatile instrument.The steric requiremenits of aspartic acid in(licate that inl a

col)alt-(liethvlenietriaminiiie complex, three isomers xvill pre(lomi-inate: oIne s-cis (symmetrical), shown as a (ashe(l-line profile in1the (Irawing above al1(1 twv) u-cis (uisymmetrical) isomers, ShONN'Iin color. The latter are essenitially mirror images of eaclh other,aindI the Durrum-Jasco instrumeint )rovi(les a way to identify onIefrom the other.The configurational contributions to the CD traces of the twN-o

mirror-image isomers shoul(1, in thleor, canIc'l out, lea,vin1g a1n'avercage trace that approximates thlat of the s-ci.s isomer wvheIlethere are nio coinfigruLratioial coitril)utiins. As seeni here, a veryclose correlatioin is aclhieved, proving that the two uI-cis isomerlsare indeed pseuldo-mirror images anid provi(liing cles as to theirslpecific forms.The Durrum-Jasco CD recorder i.s a poweirful alnalytical tool,

use(I throughout thle wvorl(d to classify anl i(leintify complulex or-ganc ani(l biochemical compotuids. In ad(lition to (letailinig theconformation- aild con-ifigruration of such1 substanices as steroi(ls,alkaloids, proteins nIu leic aci'ds ani( synthetic polymers, tlheinistrumenit can serve tomeasure their conceni-trationis, kin(etic- pi'op)er- *ties, and stereochemical - *. . o , *characteristics. Dur-ruim-Jasco CD pricesstart at $29,600.

*A 1. RE71 FIT FD Py J. VAN F'. I, A ND rFA .l W. rr I-KF- tl T. IF F-FMP Il-7 CF1Trr -'lRtNAL 'F- TW4- Alstl RltCA!. C"FM.?lAL ^'nDCIFTY.A

u r ecisely exposed otomicrographs .-,:automatically.ma ait for hours for ha micrograph opponity. Why risk

1, Iftt by a wrong meter reading? Or why take a chance on missingre completely while you'tre busy with camera controls?

>teitz OTHOMAT Microscope Camera leaves your hands and yourief more important things. All you do for a perfect photo-

h is select your field aN push a button. Attachable to mostcroscopes, this automatic 35mm camera trips the shutter, calculatesosure and advances the film. Even automatically compensates fornges during exposures! Exposures range from 1/100 second withtrnic flash to over 1/2 hour with fluorescent.

e0 sh0utter of the Leitz ORTHOMAT isf specially dampened againstration-.You can switch from black and white to color film, or vicesaX, even in the middle of a roll. Use any system of microscope illu-natitniyou want. And, of course, the ORTHOMAT is built with theous -Leicrecision.ne THMAT Microscope Camera automate your clinicali oNmicrography. Write for an ORTHOMAT catalog.

INC., 468 Park Avenue South, New York, N. Y. 10016

"mom

The TEI(TRONIX Type 502A means . .DUAL BEAMSeparate vertical amplifiers and CRT deflec-tion systems provide no-compromise viewingof two time-related signals regardless of rep-etition rate. This means brighter, sharper,easy-to-control displays.

100 1,V/cm DEFLECTION FACTORUsable sensitivity for difficult low-level meas-urements. Bandwidth is 100 kHz at 100 1EV/cm,increasing to 1 MHz at 5 mV/cm and above.Drift is typically <!400 -,V/h with constanttemperature and line voltage. Internal noise is

-typically <30 aV referred to the input.l l l l -~ ~ y PI-50FS2flA 03f.AStBEAM, 05CMt5COPF .t -.....<< -

DIFFERENTIAL INPUTSCommon-mode rejection ratio is >50,000: 1,DC coupled, from 100 NV/cm to 2 mV/cmwith a dynamic range of ±15V. Translatedinto operational terms this means the abilityto exclude unwanted signals or dc levels over

*0 a wide range of applications.

-IDENTICAL X-Y AMPLIFIERS* a The upper beam vertical amplifier can be

'Alm BEAM -switched to drive the horizontal deflection sys-W .tem. The result is an X-Y measurement ca-

0000AL900vi -}sli0iff pability with less than one degree phase dif-ference between channels (DC to 100 kHzmeasured at 100 uN/cm) and the operationalcontrol of identical, high sensitivity, differen-tial amplifiers.

j~ 0SINGLE TIME-BASEThe single horizontal sweep circuitry deflectsboth vertical beams simultaneously makingtime measurements between channel conveni-ent and accurate. Sweep rates are from 1 1,s/cm to 5 s/cm. Calibrated horizontal magnifica-tion to X20 increases the time resolution ca-pability in many applications.

CONVENIENCE FEATURESDirect-coupled vertical signal outputs formonitor/high-gain amplifier applications. Sin..gle sweep function for photographic control.

*.*.*Push-button beam finders and front panel DC,...~ balance controls. A common trace intensity

.~~***and an intensity balance adjustment offereffective brightness control.

Fo; a denionstratioit, contact your local Tcktrouixicldf10( Engri- TYPE 502A OSCILLOSCOPE ....'cicer For complete spccificatioits, consutlt y,ouri Tcktr-oni.r.... .. .................$1150.00oataloq, circle the reader scrvice niumiber or critte Tcktron,i.Jr,lC. P. 0. Bov 500, Beavcrtont, Oregoit 97005. U.S. Sales Price FOB Beaverton, Oregon

.2

| Tektronix, Inc. 1committed to progress in waveform measurement J

344 SCIENCE, VOL. 163

New thermal technique gives Matheson Flo-TronicFlowmeter accuracy without a big price tag.

FPo-Tronic Flowrmeter offers midnydistinct advantages overrotameters, yet costs little more.As with mrass flowmeters, changesin pressure and temiperatu re haxelittle effect on accutracy cfreadinc.

FEATURES. Adapted for RecorderUse * Remote Monitor1rig Use* Fast Response-2 sec. (0 to fullscale) Accuracy -_3 of fullscale * Reproductibility 2-.) offull scae * F-caur Flow Ranges-0-300 to 0-1000 std, cc. min.

~4 MATHESON IGAS PROAUBISWrite for Etigineering Report to Matheson, P.O. Box 85,East Rutherford N J 07073.

can save you time, money, and a lot of grief.With a Hardco ALItomatic Watering Systerim,lab animiials always have a supply of fresh,filtered water. There are no bottles to refill,wash or replace. Personnel are free to doother things.

Heart of the Hardco Systenm is a leakproof dispenser that can be easily activatedby a smiiall anlnia!. A dispenser is installedin each cage and is connected to the watersource by a network of special plastic piping

Hardco desigris and iristalls systernis fotrall species of lab animilals. .. for both plannedand existing facilities. Our catalog goes intothe details. Write for it today.

Hardco ScientificThe Fieldstone CorporatiornHardco Scientific Division

6811 Grace AvenueCincinnati, Ohio 45227

4t

rasolts attcliplts xx crc niot succe 'I ltil it

oht;ail coiiCil ciieiittiiin lIct\ssccii 1lic e1s nlitlntsxlix\licl-i 1d1iVllted Itom olucc 1-

)I I,I lor \xii ois (IcIlcts. [1lust diI.-cnI sszcd e-.eiit cicohinI-)IItIltsIiLid ICs

S( 1 \I(d SillV( ) I

IFOLK SONGSTYLE ANDCULTURE

Bx A\iilm 1omiia\

and1l stal 01 thei ( a ntoiiit rics

Pir' j.t. C olnin l L'lix cirsits

Go1 1cI I,LI(. 11- II oII vrC:11Si \ itiIc \IC thd"

C riiiLiiSiis tiii C aIlitoinen ic I'N-

Sirnias as> a \lcxn coil-(1 >!lni c

1)(tHCC Stix 1c and ( 'LltiL 'C

' 57> AA,94. \ 11c 1)c /-N

( s1 ()!'(/(r,.i 4. 5

AAAS

1515 Massachusetts Avenue, NW

Washington, D.C. 20005

m

0-

The finest$150. FlowmeterEver Made.

resoled h1v polvsacr lvamide eel dlcc-t ropho Cs is. -Ihese scnilmcits ranicd in]siZC t'Ironi 2.5 x 10 to 7 , 11)' d1altonssIIicli xonlid suIge2Cst tha.t th nIII"ight-ret-csciIt nioflocistrotiic seeLILce1Cs Ot

lioli lileolC'ttid'es. I dCe1uce \x as also i)tIc-scntcd. ( Pvons ) thi., thle t pl icatix C lo mr

I R F Ol inliCniaR/N \obNta,ieLCdI' 0nt5 i tnt-iIcted cells can11 he resolvcd aisfix c coiiptillciits csistant to -I hon L-

clcitsc, 1 hecsc ohscl- vatiOlls cVOkcd d.is-cnssiOIi aS to tilc actiulal phy icl staltcot tile RNA genome k itlilli inlcta i-

riMIns 5C isuIS its inti aCC11ktiat lot 11. -1-1hcst,ieees1tiOntIO r131-Mll ) thait thc RNA\ niTi\

c\ist in inlinellnia partticles aIs a sinelgc1nlc Ic huth Ia1 he IC1ilicaltCdI aS SCj_-ai attc Il inilellts appeaIrs x 0(I thy O1 con-

sididCa.t ion. 13o01s enlded hiS diSCLuSion1 ol

ph sicochilillical stldies xx ii reccnitkft.,. C'(IICC'l'lliI](_ t0]tC IIIOICC'LI11'11 {I-M,iS tof-

thIe class,ical "VOnl. NagItJIs I_hCeiioiiic-non; that iS. tIle iiitiltipl icit\-dICe)Cpeiiditpro-diict iou ol' inConipletc. Ilollnlltcct OtisHiJiLeiaC x it uS. Analv ses o1 radiolalilcdvirns lv (eCe ClectrOphore-CsiS slios eCdtIhat ttie incomplielette toloiii 01 xiIus Conl-tanied tile Same proteiti coilipolnenits atslullsV nlle'CtioLiS 5ir-usA. hLit tHIt it lackedotie ol the fi e NR A coiipoiients. Itxx ill he Of obvixios iilteCeCSt to dctermil ic

x halit etieletic tLintCioll or 1'L utioIIS thliisillissitgi RNIA seg mietit cati pctrori- r ininit.ict eeTCIIoCIIIeCS.

IFrak Feiier has bIln addocatcd theUse 01 coiiditional lethal tiltitanilts IolcirCLiII eCntitii. tthe techniical prolc,lesthat hav e haiaipered getietic studics oIaniiiial s iruses. OnIC couldll scCr-celC (do)ubtthle LIsCl tIltICess 01 this approach xx hecnicoiisinmderiii the x\\or CiiSCIscusse h\ Feii-iiiX (rOt tciii liral-t ittev+s,enlit ix, e (tsl miZatItilts Li in IC ia s iVirus. s t ra ini \S NITliesw Lklta. mniatiy derived l r-oiii at recccitdoctLral dLissei.tatlw (J. MNIackctis ic ).

sios\ ed that ociietic iiiap canl he Coil-sI [ited \x ithl inlluleIia tsilNLitatltsIlitS

dinAlme tIat colltlitiolt tot r-Ccollilhii-tiOii are lii ,Thix standardk i/CL1 iicl Itidinticattncnt 01' cclls xxith l i/iro cJtolcriit

eiiC.LimiiiIdasC. Six\teen s iiimtltlnts ()1\\VSN xi itLIs xxCec flust Ordeied ;oloii,Ii ica, tima tlhat slio\ .1d ictasollhle .td-diti\ its ;11dI ma\imhi-i Iccon2rhiiiatti0uiiCiltclcs ol(I lici-ccit. loss xec toe<solse\ the dis"ci peiIcs ol ILiss ci Iian

ci ipi.il iiLtitailts r i citiollhclarma xxI i.scowistiLicterl xx liichi Feii ici- strlisscd 1-is

cinvwil qilitc tCilta\tie. t nii\liiClinIcd

iIll-.

with similar t.s muLtants of WSN origi-nally isolated by Simpson and Hirstand he was able to group nine nonre-verting mutants within a linear mapgiving a maximum distance of 13 per-cent. Except for the suggested circulararrangement of the genetic map ob-tained in Fenner's laboratory it was ob-vious that fairly good agreement existedbetween these two independent sets ofdata.

The writer (Simpson) opened a dis-cussion on heterozygosis with a presen-tation of recent results stuggesting that,with some crosses between influienza(WSN) ts mutants, some clones pre-sumptively classified as ts or "wild-type" recombinants are probably segre-gating heterozygotes. It was suggested(Zinder) that most of the influenza "re-combinants" obtained from crosses witht.s muLtants might be heterozygotes ratherthan true recombinants, similar to theevents detected in crosses involving am-ber mutants of bacteriophages (fl). Someparticipants pointed out that good evi-dence for the occurrence of true re-combinanits of the inflLenza virus exists.However, since the very high recombi-nation frequencies (10 to 13 percent)of inflLenza ts mutants remain unex-plained (considering genome size), it isnot at all inconceivable that eithergenetic or replicative heterozygotescouLld account for this anomaly byexaggerating and masking true recom-bination frequencies. Evidence was alsopresented (Simpson) that stocks of theinfluenza ts muLtants contain a largeproportion of virus that is noninfectiouLsbut genetically competent in recombi-nation.

The genetics of paramyxoviruses wasdisCLussed by Simon who presented datafrom a dissertation (J. Dahlberg) on tsmutants of Newcastle disease viruLs(NDV). These workers performed com-plementation tests with 48 ts mutantsthat fell into eight or nine groups al-though there was strong clustering with-in a single group. While segregationanalyses or other tests for heterozygosiswere not carried out, it was concludedthat recombination did not occur (<5 x10- ) with these mutants and that all"'ts-" clones were actually complement-ing heterozygotes. Simon presented evi-dence that populations of NDV are het-erogeneous with regard to their ploidy,many particles incorporating more thanone genome. The occurrence of ploidyand heterozygotes among myxoviruses(influenza) and paramyxoviruses (NDV)has long been recognized but it is ap-parent that their full significance in24 JANUARY 1969

genetic interactions is yet to be evalul-ated.

Pereira closed the discussion on ge-netic recombination with a review ofhis work on interaction of human andavian strains of influenza A virus.Using the techniqUe of cross reactiva-tion, it was shown that reactivation offowl plaguLe viruLs with different humanstrains of inflUenza resulted in trans-fer of the genetic determinants for neur-aminidase protein of the helper virus(noninactivated human serotypes). Thepolygenic nature of these determinantswas suggested. The final discussion top-ic of the genetics session involved therecent work of Chanock and associatesconcerning progress in the developmentof vaccine strains employing attenuatedts mutants of various respiratory agentsincluding respiratory syncitial virus(RS), rhinoviruses, and even Mycoplas-ma pneu,nloniae. The desirability of iso-lating such muLtants with presuLmedaffinity for localization in the upperrespiratory tract, where they should becapable of stimUlating local productionof IgA-type antibodies, was suggestedby the finding that circulating anti-bodies actually exert an adverse effectin the case of infections evoked by RSvirus. The successful isolation of sev-eral ts mutants of these respiratoryagents was described (Chanock, Per-kins, Steinberg). One now awaits anexperimental confirmation that suchmutants will be as useful as one mightanticipate. Appearance of virulent re-vertants may be precluded by selectionof appropriate mutants under condi-tions where multiple mutations are al-most certain to have occurred.The session on the biosynthesis of

influenza virus and its components wasdisappointing in the sense that no newdata became available shedding light onsome of the enigmas suLrrounding thereplication of these viruLses, stuch as thenature of the actinomycin-sensitive,host-controlled ftunctions. Pons reviewedhis earlier work showing that actino-mycin D blocks formation of the influ-enza replicative form of RNA. It wassuggested (Braun) that some insightinto this problem might be gained if theinfluence of agents stimulating nucleicacid synthesis (for example, by oligo-nucleotides) were investigated. Zindersuggested that a more critical examina-tion of the effect of protein inhibitors,added late in the infection cycle, onviral RNA synthesis might be war-ranted. Interesting new findings con-cerning the surface structtural proteinsof influenza virions from stuLdies of

Oxford (

Physics: AN INTROI TI( N('oei1 s' 11/i's Nirs)By, ERNES I C. POLLARD, PennsylvaniaStoite U'niverssit/ anid DOUGLAS C. HUS-TON, Skidmnore College. In this highlyteachab)le 1)ook, the auithors create astimuitilatinig text for the IlOnlscientce sttident.The centi-al theume is the conIcept that thetnIlsceei t cal wooldl, revealedl hv' science, isbeantiiftll. Mathemnatics is tusedl, iincludingcalculuis, hut its iintro(ltictiotn is remark-abls clear, ani(l no hack-round in calculusis ileqtuirel. Inforimative figuires and dia-gr-amils, prohlems wtith soltutions, bibliogra-phics, and(l an inl(lex coImipleIlleim t th-e study.1969 -1 l( pp illtns. $8.50

Quantum-StatisticalFoundations ofChemical KineticsBy SII)NEY GOLDEN, Braldeis UTniver-sity. This wvork examlin1es the mathematicalpropertics that are recluired of the statisti-cal ope a.tor of von Neuimann and itstrauisfot-miationis in orrler to faithfuilly re-produice the mc'iasti able dynamical hehaviorof Gibhsian ensembl)es in nonrelativisticquiantum-mcclianiical terImls.19(68 128 P). paper -8 1.00

The Structure andProperties of WaterBy I) WID EISENBL1RG, Uniaversity of Cal-ifornil., Los Ansi eles, anid WTALTERKAUZTMANN, Prinreton University. Corre-latitng mnany expet imenetal and theoreticalobservationis fi-om the scientific literature onwater, this text emiphasises the relationof the ploperties of ice ancl water totheir strtuctures. The topics cosered incltidethe wvater molectile and forces betweenwat(- molectiles; the thermodynamic p3rop-pIerties of steam-ii; an(d Imio(dels fot liquiid

9(69 31001)1)P 7 tcxt figs. papPel S 6.00clotlh S1 3.00

A Dictionary of GeneticsBy, R(OIBERT C. KING, Northlwzestern UT[ni-Ver'sity. "A utsefuil dictionarv for the hiol-ogy libh arN, for the geneticist, and thesttil(lenits of genetics.'-Philip E. Hai-tmana,Johnis Hopkins ITnjijesitNs1968 32-'0 pp). 250 ilitis. pa)per S3.95

OXFORD WUNIVERSITY W

PRESS W200 Madison Avenue,New York, N.Y. 10016

411