442 



NAi uRE 



n 



of till' ■>ii!>ii M>|)Iiil(Pii~ \r ill 



(lislrii !•, w ii., ., .,..<,, l,,iii 



m(inili> I r .1 liiiii 



and i!i'. ■ -, im n;- m:;; \\\> .;i.i---> -iiji|)c^ ,i 



(lilTriri; , ilii- (ii\ uixKl-arul !)Usll.f(Jrm.•|lil>n-^, 



and sul'.;!; ';iii .unl alj. ; and. Iiii.ill\, iln' itiM 



\ciii[iliili -as loiinalii.i f'unali .uid l.i--t pai; 



contain^ ni .LdmrM !■ I mdi-i-^ and 



jjrni 1 .1 d; -1 I.i\ in^ ili. !ii clrimii'-, <,f 



til' ' :"i iia. --ui li .1 : i li ii|ii('al 1 I'liirnt , 



I'll \ I III I ' , - \ A ! lir.ii 1 - M , . 1. 1 L;a>\', 



M-.iM- \ii-i' dcmic 



Ml', .11 li. .iiiii .uiM-is. li;'i'- I- aUii a vii..ii ^jviicll of 

 till' di-\-.diipin(nl of llir Alrican llora. 



'I'hc ditVuad! iimMini <:l indixini; --n i\t( n^l\c and 

 elaborati^ a s\|i-niaiic work has \^^.■>■\\ -.^AwiX \)\ ~-u[)pl\- 

 iiu;, iisli\-.' laMi' it (I iihnK and li\ (■(UilininL,' 



til' names nt |d.inls which .ire fiLjurrd in tho 



t<"xt. A. H. R. 



•/■///•; 1/ //•,/,' \ w v.-c\ K\<i:\ \ lu lxs/V'/m //•:/;. 



'/'/an; ^/ ■ )-•,» s ; ,( I' i,,i I i ■.,■ .ni III,' I'luiny. ('(Oislruc- 

 li'>:. ;'. ^.'.a:'. (iinl I >•■> "/ T r,nis foniurs . Aiito- 

 tr,inyh n,!, rs. ,ni,l ('/;"/,■/(;- ('nil.s. I^\ Pnif, II. R'llilr 

 and i^;ii. 1). R(.h,a-|s,Mi. V\k \iv i 35h f d^ddis A 

 and \l ■ iS plaics. (I.diidnn: ( '. (.riflin and ("0., 

 Ltd., I'd i . ) Price _> IX. net. 



TIMS \er\ ci)nii)Iete treatise on thf alternate cur- 

 rent <ir si.itic tr.anstornier will no doubt be found 

 of consideraMe v.due in the drawiiiL: office of prac- 

 tii-al lranst(irnier hnilders, ami also bv tcacliei's and 

 advanced stmjenis. WiineNcr uses it. howe\-( r, will 

 ha\-e III |il;^-,-,s time .and palience as well .as \-cr\- 

 -Odd e\,si-^iu to master ih,e s\ ml). ilical nolation the 

 •aulluiis li,i\-e >een lit to employ, which to most 

 ordin.ary re.ideis will prove in certain respects 

 exaspt raiin-. In de.iline- with simple |)eriodir or 

 variable (.|uanlities, such ,ts ahernatinj^ currents, 

 electromotive forces, ,-ind Hums, ;i widel\- used custom 

 h.is b<-. ii adoj.ied of enip>lovini,'- small letters for 

 instantaneous \-.dues and coiaa-spoiulinL^- l.art;e ones for 

 the m.aximuni \-alues, ,and eiilna- iM'.ackets or bars over 

 a K'tter to d.iiote R.M..S. v.alues. 'I'he autluirs ol" this 

 book h,a\e .idopii-d ihi' jilan of printiiii;- a little • inside 

 the ca|ntal letter to denoti' the instantaneous value. 

 and ,1 little ^' to denote the m.aNimum v.alue. These 

 sp.cial s\nihol<are for most • \--^ unite illeeihle with- 

 oiil the aid of a maenif\in^ u'ass, -ind can onl\- be 

 described ,is produciii!.^- the m.aximum amount of eve 

 and mind str.ain to read them. 



.\i^ain, most m.athem.atic.d writers now t niplo\- b!oid< 

 letters (ir clarendon iy|)e to sii4nif\ \. ctors. liut the 

 authors e' ihiv book have turned their b.acks on iliis 

 useful practice, and used block letters sucli as T and 

 N to siij^nity scalar quantities such as tinua or mere 

 numerics such as number of tuiais. This m.!\ s.t m 

 to the non-mathematician to be a Miiall matter, but ,at 

 a time when an International Committee is entU'avour- 

 iny- to obtain sometbin.i;- like order and uniformitv in 

 lechnical symbolisation, it is a i^reat pilv for any 

 authors to display an exuher.ance of in^enuiiv in 

 devisini;- symbols which ha\e ne\er been used before, 

 and are not likely to be used again. 

 ■ NO. 2i;o'. VOL. 86] 



\p.irt, hirwiver, Iron) llii dillicu 



M,'r.„i;,, , ,! I,-. li.i. a, ^ ■. -;.,.. I,.,,-: 1., 



I I .1 1 ion s p; 



1. s' , W i IK I I ail 1 el i(ie| , (1 ,,ll 1 



appended millinieiii- .imi inch s, 

 111 ] (■ are .lis, , ;i |.!i .'e number 



I , 1 . - '. . I I ] . I I 1 1 i M , . ■ : . I : - ' . ! i n 1 1 1 1 



valu- 



e.\ctlk-ni 

 >rmf'r«; in 



•i,' ■ 



losses in Ir.aiisloi iner s, teniper.aiuri 

 li akai;e, transformer vector dia>.,'r;mis, systetnalic 

 tistiiij insulating' mat^-riajs, ex.imples of construc- 

 tion, (le^ii^ft of ir ~, .applications of trans- 



lormers, ,and poi\c\i :is. Il.avini; rei^.nrd to the 



tact that so much h.as iieen writ ■ of 



I ra Usti iiai ii 'I's i liei , i -,:!■; i ii i ; 11 



The subject of the 

 h;is ''' ■ ' ,ited fn -in i ;i'' i'< ''■: 



iheor\ the student with s^ 



in the w oi !vs of Blake-^ iin;.;, Kapp, Lkuvii. 



Hed( 11 .ukI Pierce, Rhode aanv others that the 



chie; room lor addition sec-nied to be in a practical 

 treatisi lin ihe desij^n of transfonoei^ ■ivin!'- rntes 

 for th' atic predetermin.it; 



and Lju.iiiiMiis to a prescribed s,, , ,,:t^,,, ,, ,.,. 



This the authors ha\e i.loiu- in ilu-ir eliiip' 

 ,111(1 h.ave .addid also complete w ' ' 

 tioiis lor traiisteirmers and chok: 



sizes and lyp's. Thes,', howe\tr, would have t>een 

 rendi-red more v.aluable if ib.e .ictual results of tests 

 <it these tr.aiistormers ha -en to show h 



the predetermined \;ili;i - ''i' m, :i,iii-,-i' 



The chajiter on 

 deficient in not l.i\iii^ sunn niu sn.s^ up^;: me 

 measurement ol s,cond.ary drop or ,^i^"iI'!,:.^ j.,a>od 

 iiKMhods for determiniiij^' it at ,all loads. When trans- 

 formers iia\c to be li.ndced to work in p>aral1el. the 

 iihaitilN' ill their ilroji cur\'' - is 



otherwise one or more ii;; - r- 



loaded or may overluat. a- 



j^rams for traiisf()rmei" i. ^v,,,,^ ;.. ,.• ^^ . > ^ . . j„,.<.-n 



and I'xplained in the cha]iter on ir.msfetianer diaiframs. 



It would require much time .and. in addition, con- 

 sideraliie e\|)ense to check or test the formub'V iriven 

 by the .authors Icr dimiaisions of tran^ 'o 



com|)lv with certain sjiecitied rei.)uiienua.: - ae 



results are for the most ji.art en ' -' d 



into t.ables, which the practical tr.n.- ii ...i i i...a.ui.iC- 

 turer can spccdilv brim; into comparison with practice. 

 The lxH)k. however, in m.anx' resjiects tllL a distinct 

 i;ai) in tr.ansfornier literature, and will no doubt be 

 o( ^reat use to draughtsmen wh - '>nsible for 



overhauling or improving a line i - .msformers 



to riduce cost or im|M'ove their working. li c)nly 

 remains to add that the book is excellently printed, 

 and in this respect a model of what technical publica- 

 tions should be. 



