478 



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[February s to 12 



-liW t(i lllr Sinillisoiii.r 

 1,, ^ ;;ii- ~,| up .-1 llil^h staili' 



tidll, we inilsl lollii -- 111 .1 li-i-liii;; <ii ^ 

 tncril oil .-l Cliru .ll . - m: i!^ li :< 111 ( . ,1 



villi .(lilinll uilll !■ '11 j 



,1,,.-. Ilcil ^1' 111 111 ll.iN !■ 1"- M .i- Ml ,1 -I n .1 - 1111,11 11. iM' I 



1,,., II ,\|M iirii, .111(1 -umr III ill'- clmn^.^'-s .-ippi-.n- to iIk- 

 wiilff In lit' (loiililtul iiui)r()vcniiiiis. ' 

 iiui'-t III' llic (•(invt-nicnlly ;ii'r;in}.^c(l t.-ili'i- 

 tacldis occupvin^ llir lir-~l Iw i-nly-scv > n p.u;' - Im*' 

 (lis.i|)pr.ir.-(l. ' W'liili- mil ui-sliiiiL; In ctilirlv,- iniLiirh, 

 ,,,, i.miiiii-- .luil iinim iiiK ii^ctul a \\iiii< .1-. ih' -.> lalili-~ 

 li.i\,- Ik 111, uc iKiiicr I lirdnLihiuii ,1 'j^^^^A d. M i>' ( ..i-.-- 

 1i-,-sii(w in (iriail, wlilcli ini^ht i-.f-^ih - n 



(iliviatcd liv iiKifc iiiru'al |)i(uif reading. </ii' m lin' 

 Tiiiisl sit'hhis i^ciM lal lilcmishc^ is a pmiKiuiircd tfiid- 

 (•iir\ iiinlimiallv id nii-^iiill pnipi-r n.nni-, and an 

 i-\ira()rdinai-\ lack dl -x^trm s.tiiin Iu lia\r (iipi in 

 rci^ardiiiL; tin- \va\ nt indiratini; joint autli()t>hip of a 

 paprr. In about iialt tho instances noticed, the names 

 of tlic iwo authors have been hyphened tot^i tlur witji. 

 at limi<, ciiriou's results. " Robcrls-Austcn " we 

 kiKiw, liui whci i-~ Mr. " Baly-Ramsay " or Mr. 

 •■'i"hori)i -RtiLici- "? With "Thomson-Houston " overv- 

 one is acciuaintcd, hut we confess to U-ai-niiii; with 

 considerable astonishment that specific In at dttcr- 

 minations were made by Mr. " BariHs-R( i^nault." 

 On the nilii r hand, Ayrton and Perry, Hi\(<ick and 

 Neville, i'erdi and Fabry remain "dissociated." 



There is a considerable lack of critical faculty in 

 the choice and mode of presentation of some of the 

 data. From a comparison of the -ia\ii\ 1 iM. - in 

 Kaye and T.aby with this volume the meaning of this 

 criticism will at once be evident. 



In the chemical sections of the work the nomen- 

 clature is often lacking in system. Thus we find on 

 p. 232 "Nitrogen fc/roxide NO,," and on p. 212 

 "nitric />6roxide N2O,." The hydrocarbon C^H^ is 

 spoken of as "benzene," "benzol," and "benzole," 

 and is also probably intended in at least one instance 

 when spelt "benzine." This last name is used, in 

 this country at all events, for a quite different body, 

 which is a mixture of saturated paratViiis of low 

 boiling point, variously called benzoline, petroleum- 

 ether, and petrol.^ 



A chemist travellini^ with his impedimenta, say on 

 the South-Eastern Railway, will be able to ascertain 

 from the table on p. 85 that if he took with him a 

 cubic foot of caesium, he would have to pay excess 

 luggage, that quantity being stated to weigh 117 lb. 

 The only mention of radium or radio-activitv or of the 

 rarer gases of the atmosphere e\crp; ar-on i-« in tlie table 

 of atomic weights, and ionisation is only treated in 

 the chemist's and not the physicist's sense of the 

 term. 



The table of melting points of inorganic compounds 

 is misleading in that from it one would imagine that 

 many of these substances melted over a range denoted 

 by the limits "max." and "min." rather than at a 



^ In table 31 of the old edition, " Conversion of quantities of hea'," mar.v 

 of the figures given were wrong by 10*; thus, i B.T.U. saszgrm.-cilories- 

 not o'ooois as staled. 



- Strictly speakina;, these terms are not synonymous, but are applied to 

 different fractions of the same product. 



.lU 



un- 



f.itniii.ir uniu ■ w p.-ople will be able 



to d. fin. ■ "i " 



i In \,i latinum 



'.11:1 1.; .{pj M d\ iiii.i ii-i '. 11'. i 1^,000, 



iH.irh 14,500, .and ili< i.rjuction of 



j,i.,:, . ti r n-.idinj.i>~ nenlr.n'd in the title 



1 ,11 j,, . . li.ive drojijx-d out. 



Alter nirntionin.u tli'S,- (i should, however, 



\^^■ -,i,it.(l tii.ii the book h: i*f)od points, the 



malln ni.itit li tables cc)mprised in it liein^- in par- 

 ticul.ir ,1 very useful selection. 



A ( diisiderable list of minor nii-[irii in- 



accur.n i."^, too long for inspr(i<in lure, lhi> w . u pre- 

 partfi and i-- beiiij^ forw.arded to the author. 



I. A. Til 



NO. 2206, VOL. 88] 



VR\c\]c.\]. .i.\7) 'ii!i-.(^in-:iJ(\\L i'ii\>ns. 



(II .\.'/(V ,<n I'raciiiii] I'Uysus. Hv Dr. A. li. I-ivon. 



rp, \iji • 144. (London : Ldw.trd .Xrnoid 



i'ric- ,v^. <||/. 

 (.•) C.'llr'i:,- I'hv.'^lcs. r. I" J. <>. R'-'i -nd I'rof. 



Karl K. (iuthe. Ljj. xxviiirfu.'. iN.w York: 



The Macinillan Co. ; London : Marmillan and Co., 



Ltd., i()ii.) Price 12s. net. 

 (OnpHIS little book treats of such an el.-mentary 

 A course of practical ])h\ -ics .is is usually pre- 

 scribed for medical students in their preliminary scien- 

 tific irainiiiij:. As its title sut^i4r-.ts, no attempt is 

 m.ade to i^ivc ,in account of the theory o! ' ■ \iieri- 

 meiit or even a complete de-scripition of lii duct 



it, but there is enough to save a demonstrator much 

 wearisome repetition, and allow him to devote him- 

 M-lf more to a discussion of each experiment, and to 

 removing t;? dithculties of individuals. There is no 

 " spoon-feeding," but, on the contrary, attention is 

 directed to tho pi inciples involved and to possible 

 difficulties .and . rrors in a \\ay calculated to encourage 

 thought on the part of the student. The book should 

 prove decidedly useful, and, if properly used by 

 teacher and class, should increase the educational 

 value of such a course of practical ])hysics. 



For each experiment an im[Hniaiu indication 'is 

 given of its general character as regards accuracy, 

 and the author insists on the importance of consider- 

 ing the degree of accuracy attainable and of seeking 

 that, and paying attention to no more than that, in 

 the various observations and measurements to be 

 n\ade. 



Some improvement in details is desjrable. The 

 treatment of mirrors should be independent, and not 

 derived from or made analogous to that of lenses. 

 If necessary, space for this could be obtained with 

 advantage by omitting such an experiment as the 

 determination of the earth's horizontal component of 

 force, which could only be treated very partially. 

 There is an occasional pandering to students' weak- 

 nesses, as in permitting the use of a chosen length 

 for a simple pendulum in order to save arithmetic, 

 or as in taking loo c.c. of water in a calorimeter and 



