a wny ns to make the book an cxccllent guidc to tlic studcnt, by whicli hc can understand wlitit lic is nctmdly doing to the fnbric in each proccss iind carry out liis work intelligently. To the cxpcricnccd finisher nlso the book will bc of grcnt vnluc, by rcnson of its siiggcstions on many points which mny hnvc I m n obscurc, and because it will often hc foiiud to confirm tho knowledgc of long espericncc by rciisoiis which nrc clear and con- vincing.

The question so frequently prcsriitcd to tlic fiiiislier of deciding \d in t mncliinc t,o use, and wlint vnricty and tinic of trcatmcnt to use to gct :I pnrticiilnr result, will find a logical answer In tlic mind of nny fiiishcr of expcricnce d i o hns taken the trouble to mnstcr tlie contcnts of this boolr. Finishing will a lwys rcniniii nu nrt which cnnnot bc lcnriit froni ib book, but this work hiis thc grcnt nierit of prcscntiiig the rcsults of cspcricncc in the art in a logical form, niid tlic rcvicwcr hiis confidcricc in recommending it very highly to all who arc cngagcd actively in finishing, or to whom the results of finisliing, good or b:id, nrc of intcrcst arid iniportnncc.

SOLVENTS. By T. 11. DURRANS, DSc. Series of Monogrirphs on Applied Clicniistry. Vol. 11'. Editcd by E. H. TRIIT, 1'1i.D. Yp. xi $. 144. London : Chapman SC EIall, 1930. 10s. rid.

It iy significant of the timcs thiit a volume with the above titlc should contain no nccount of turpcntine. Thcrc is no doubt, however, that in tlic past fcw ycars

conspicuous has been that of I' ccllulosc " lacquers and cnaincls, and thc titlc stands as a reminder of n delinition now tacit.ly acccptcd by niany, for Dr. Durrnns confines himself to this ficld. At the snnic tinic it would linve coniplctcd tho story if sonic trcutnient of tmpcntinc had h e n incliidcd, iis this omission is thc only uotnhlc one, cvcn among the older solvents, whilst much infor- mution that lins recently IJccii iiiadc acdablc in n widcly scattered fashion hns bccii collcctcd together for the first tinic.

The first tliird of thc voluine, dividccl into eight short chapters, dcnls with tlic gcncral propcrtics of solvents and considcrntioiis governing tlicir sclection. Thc trcatnient of solvcnt action and solveut powcr is quite reasonably confinccl to ccllnlosc riitriitc soluti ns, whilst solvcnt, balnncc, viscosity, and cvnporation arc adequately rclittcd to tlic othcr tlissolvctl Incqucr coniponcnts ; liricf discussions of inflnniinnbility and tosicity round OR this section. Tlic sniull spacc occupicd by this part of the 1)ool; is not n fair indication of the mnttcr it contains, but a regret niny be csprcsscd that, there is not n bricf clcscription of the ccllulosc dcrivn- tivcs with wliicli t h solvcnts nrc used ; such iiii account would linvc I)cen very p c r t h m t , IJotli froni n priicticnl point of vicw and as sliowiug tlic way by wliicli tho solvents indiist,ry lins itttnincd its prcscnt iniportant position.

In the second and lnrger scctioii lire dcscribcd indi- vidually a largo iiuiiibcr of volntilc and plnsticisiug solvciits, classifid ns hydrocarbons, iilcohols, ltctoncs, cstws, glycols, cydolicsniic dcrivstivcs, chloro-coiii- pounds, furfurnla, and plasticising solvcnts. Tlic itiiioiint of information vnrics, and conipriscs gunorally n bricf

t1lC field iJ1 Which SOlVCIl t dCVC~OpJllCIltS h n V C bCe11 J l lOSt

account oE innuufncturc, physical characterirtics (to- gether with IL brief sutninnry of tha appropriatc B.E.S.A. or otlicr spccificntions), and solvcnt propcrtics. IVhcrc varioits tcclinicnl grndcs arc avnilablc t,hcse nre de- scribed. and the proprictary or tradc nniiics arc also given. Tlic plasticising solvents dcscribcd nrc rcstrictcd to syntlictic coiiipoiinds.

Thcrc is ii certain luck of uiiiforniity in tlic prcscnta- tiou of physical data, which n t timcs arc biiricd in thc tcut. Additions wliicli should bc mndc to tho list of abbrcviations uscd arc S.TE., specific heat, and D.R.. dktillation range ; latcrit heats, whcrc givcn, a re in small calorics, not lnrgc calories ns stated. Por prcliminary rcfercncc, tables of tlic pliysicnl data of thc solvents describcd would linvc fornicd 1111 appcndis of great scrvicc, niid thcir inclusion in futurc cditionv would cnhrincc tlic valuc of the work.

Tlic voliirnc is, howevcr, ii iiiinc of information, and its stout paper and lcgiblc typc fit it for tlic constant. IISC it is likcly to rcccivc. G. c. tkI"J!lzIELD

DYEING AND CLEASING : A PRACTICAL ITANDBOOK. By F. J. FARRELL, i\I.Sc. Fifth cdition, entirely re-written by F. I\'. Walker. Pp. xiii + 328. London : C . Grifin & Co., Ltd., 1939.

A now cdition of AIr. Farrcll's book is long overdue, and it.. preparation after nn intcrvnl of 21 ycars is justly dcscribcd on tho titlc page as n re-writing of thc wliolc volume, for, as BIr. Walker points out in the prcfncc, dcvclopinents of B far-rcncliing kind liave taken plncc in all branches of thc industry since the first publication in 1908. Tlic ncw voluino contains nearly 100 pngcs more than the old, and the nintter has been extcndcd and brought up to dntc in n workmanlikc manner. O m outstnnding diffcreiicc appears iilrcady in the

first chapter : thc increased iniportnucc of artificial silk. IIcrc tho well-known danger of propliccy is illustrated by Btr. Farrcll's reinark that I' Tlic proccsscs likely to prove successful in thc futuro are thosc dcpcnd- ing on the solution of ccllulosc in cuprainnioniuni or zinc chloride," the facts being, of course, that thc viscosc product, wliich he disniisscd in u sentence, und tlic ncctatc process, tlicii in the cxpcrimcntal stage only, now enjoy pride of place. A refcrcnre to iin- niuniscd cotton is niiotlicr ~ i c w fcnturc of intcrcst.

Tlic information rcgnrding the naturc tiiid clioicc of a dry-clcnning spirit hns been grcatly aiiiplificd, snd tlic scction dcnling with the purificntion rind recovery of spirit illustrntcs tlie advanccs niadc in 21 ycars. In 1908 i t wns written : I' Tlic only sntiuftictory inanner of purifying nnd rccovcriiig soilcd bcnzinc is by distilla- tion " ; no\v Nr . Wnlkcr dcscribcs in detail various iiiethods of purificntioii under tlic licndings (1) coagulrr tioii, (2) ccntrifugal scparntion, (3) distillation, and (4) filtrntion, this last division including tho strcniii- line filtcr and tho inctliod of Hittficld nnd Alliott (this JOURNAL, 1928, 139-152).

In tlic scctioii 011 wct cleaning t h o is n liiuch fuller trcatnicnt of thc npplicntion of hydrogen pcrosidc nnd sodiutn pcrosidc ; ;i rcfcrcncc to sodium perborate occurs for thc first t h o , i d tlic instructions for tho iiso of hydrosulpliite hrrve bccii roviscd to iiccord with

12s. Gd.

modern practicc. A new section ou starch solvents incluclcs a description of the more rcccntly iiitroduccd products, such ns Novo-Fcrma.jo1 and Rapidase.

The cliaptcr on dyeing occupies 92 pages, and it is diGcult to discoucr without careful coinprison how inucli reninins of thc original work. Some of the n e ~ features arc colour-a~atcI~ing lariips, Pennutit type of watcr softeners, JIoncl iiietal dyc-vcsscls (other non- corrosive alloys might wcll have beail mcntioncd), and ncw typcs of dyeing tiinchinos in wvliich tho goods are inovcd in the dycbath by tiicans of compressed air. A useful section deals with colour solvents and pcuctrating agents siich as Tctracamit, Nelml, and Oranit. Stripping metlioils arc inucli inore fully described than bcforc, find tlie important problem of tlio dycing of fnded goody is ndcquately trcrited.

Tlic lritcr chapters contain brief descriptious of special proccsscs nnd nicthods, including ‘ I dq. dycing ” end the dycing of skin rugs, furs, feathers and hats. In dcscribing tlicse operations only gcnonl guiding priu- ciples can bc laid down, for, owing to tho fact that alniost cvcry article rcccivcd for re-dyeing lins its own pcculisr problem, n widc cxpcricncc is an cssciitiai nddit,ion to ’‘ book-lcarniag ” for success to be assured.

Thc supplenicntary ninttcr includes a chart illus- trating colour hnrmony and contrast, a inenioranduin on thc \vcigliting of sill;, :1nd f description of tlic prc- cautions to IJC taken against risk of firc nad csplosion, including tlru relevant section of tlic report of thc 1)epart- rnrtnt:iI Coiiimittcc on Dangerous Tmdcs. This last featarc is of cstrcnie vnlnc, but inigtit havc lieon im- provctl Ly i i clcarcr distirietiou bctwcen reprints and regiilrit,ioiir iiiid tlic author’s own work.

This is indisputably tlic Lost iiiodcrii work oii the subject publishctl in this country, and tlic dyer or cleaner who ciinnot8 (Lcrive I)enefit from rcnding or consulting i t is beyoi~tl ltopc.

~ ~ l X i l S t \ I . l > 8 R O W t i

COAL ~ A I t I ~ O S l S ~ Y l ’ I O X , Isy It. ~\‘IGOISTON, 3I.h. 111- dust,rinl Olicinistry Scricu. Edited by E. dc Barry 13iwrict,t, II.SO.~ ruid othcrs. Pp. x + 287. London : 13trilIikre, Tiliddl k Cox, 1029. 31s.

The wry large ~ n i o u t ~ t of rcscnrch work w-hicli 11:~s bccu ctirrictl oiit, bot,li in this country i i i d elscwhcrc, with the object of obtaining n clcarcr insight into tikc .nature of cod iLxl(1 into tlic many cliangcs wl~ich ticconi- pany its carloniuation, Itns for result tlmt thc literature of tlio siibjcct assunics iilmost i~nni:uingc:hlc propor- tions. Tlic stuilcnt is apt t o find coiisidernblc dilfculty in correli~ti~lg tlie rcsults of the \rarious rcscnrohcs to obtain ii clwr itlea of the prcsont state of 1~1~0~vIedge on t h o siilIjcct. This difficulty is i~~crcasctl by tllc fiwh tiifit many vriricties of coal how bccn used for t lmc iovesLi- ptions, oltcii ruider widcly dificring cspc”i1iiont1~1 cotidi t,ions.

2’110 )wok under rcvicw ought to lcsscn consitlerably this tlilHculty. Tlic iwtlior IIILS written the hook \vit,h tho wowed niciin object of giving nn outline of the choniistry of cord c:trboiiistrtion from the acndcmic rntlier tlian the tcchnicnl point; of view. Such R treat- rneni of tho suljcct, without; the compiicnt.ing ctctiiils of plwt constructio~i, is to be ~vclco~nccl.

The first 31 pagcs arc dcvoted to the early history of coal carbonisation, the subject being dealt with in such a niaiincr that the accouiit is most interesting and readable. The nest 28 pages contain an account of hter developmciits, brief descriptions bcimg given of tlic various types of high-tcrnperaturc retorts nad coke ovens. In addition, nine proccsscs of low-temperature carbouisation arc outlined in a very brief maiiuer,

The ltirgcst scctioti of tlic I~ook, 78 pngcs, is dcvotecl to thc consiclcration of the action of iicat upou the various types of coal. Suggcstcd methods of classifica- tion of conl arc discussed, thc author poiutiiig out the iniportancc of tlie analyses being coiisidcrcd on the ‘‘ piirc coal ” bnsis suggestcd by Tideswell and JVheelcr. Tlic cxpcrinicntal data from work on tlic constitution of cod arc quotcd a~icl carefully discusscd, tho oviclcnco in support of the opposing thcorics of constitution being esamined. The sccondary reactions of the products of licnt upon conl rcccivc consideration. In this scction of the work thc rescnrclm of WLiccler and collsborirtors ;ire giveii sonic promincncc.

l l i c succeetling chapter, 34 pges , dcals xitli the cornpositiori of conl gas arid tlic various rnethocts of purification, coimidcred from tlie elicmicd stmilpoint. An cstcnsivc section, 45 pgcs, is tlcvotcd to tlie

tlicrni:il dccompouition of ammonia and thc recovery of aiiimonium sulpl\:itc. This subject recciws, perhaps, niorc consideration tliaii its iiiiportcrncc would warrant.

Ncst follow 20 ptiges given to high- arid lo\v-tcm- ~icraturc tars, the cl~cmicnt imture of each being dis- cussed and IL cor~ipariso~i drawn. In addition, there is a (Iescription of thc usual metiiotb for thc working up of Iiigh-temperature tar.

l‘hc concluding chapter an coke brings togctlicr tlic vtirious tlicorics which Iinvc bccn advanced t o csplain the mecliaiiislism of cokc fornmtion, tlic iniportant work of diidibert on this subjcct rccciving particular attcn- tion. Tltc etfccts of blending and prehcating of strongly swclling conls are considcrcd.

Thc book cout:iins mi~ny references in tlrc for tii of footnotes, and, in rddition, tlicrc lire good rrutlior nnd subject indices. Tlie worl; is well prcscutcd, r ~ i i i l is singularly free from misprints and errors. The graphs are in gencral clcnrly rcproduccd, but exception migbt

on ~ingcs 97, 120, 122, and to thc cxtreinely anall scnlo of tlie grnphs on pigc 104. The boolc shoiiltl for111 a incist uscful addition to tlio library of all connected

, I

~ C ~ ~ O l l i l b l ~ b C takC11 to thC Slllfi l~llCSs Of the tJf])C O f tll0.W

with coal carbonisntioti. 11. h H U G E 1 T

I’IIARSlhCEU‘L‘ICAL k’0RMULAS. 13y s. G. jirOOLLEY a i d C:. 1’. Folr~t~s~eit. 10th cd., revised nud rewritten. \fd. I. l’p. svi + 1146. I~ondon : “ Cliotiist and Druggist,” 1929. 15s.

First publislietl i i i 1898, this well-known work of rcfcrence lias now rcacliccl its tcnth edition, wliicli is a credit to tliosc conccrncd in its l~iiblicatioii. I3ricfly, the book consists of IL most coinpre?icnsivo colleclion of pl~arniiiccutical forniiilio, both oflicial aid iion-oflicitil, froni a variety of SOII~CCS, togctlicr with bricf noicu on lklCthOdS of prepimtioii, uscs, aiid so on. Tho scope not only cmbrnccs a variety of mcdioinal, cosinetic, ~ u i d sirnilnr products aufRcicnt to sntisly any ~iocd, bnt, nlso