March 17, 1910] 



NATURE 



consisting as it did in many places of the large-tvpe 

 sta ements of the treatise, without the smf^SS 

 T TTl' ^^-°-trations-was too strong rnSI 

 for the babes of the Glasgow class. The mut^red 

 Srroans of the students, when on Fridav T^^Z^l 

 would first ask them to read twenty or tLtyp"^^ 



lane and tell h,m to see that questions were set on the 

 part prescribed in the forthcoming Monday moi^in' 

 exammation paper, never reached his ear, anHTth f 

 bland srmle as if he had just prescribed a nove for 

 Ind h- trr'e!^^ "^^^ ^^ "^ '^ ''^^ ^^ ^-^--n 

 \\'ith regard to the somewhat strong remarks which 



cTusn". To'' '"/• ^- ^^ ^° ^^^ absu^di^ "of 

 causing Thomson to teach elementary phvsics 'it is 

 right to say that fifi .846. when Ae 'sought and 

 obtamed the chair, the plain everyday dutf of the 

 professor of natural philosophy was "to tLh the 

 natural philosophy class, and that, so far as Thorn 

 ^on was concerned, his time, energ^, and oriS 

 power were far from wasted in meedilg from dav to 

 day his band of students, most of them eager To leU 

 and i^any of them willing to help in his research^' 

 There is no doubt whatever that the attempt to teach 

 them gave him inspiration, and from them came as 

 another m^portant reward, his laboratory corps who 

 helped him so much. Witness the tribute^ ; the 



Mor"e:>L"ft T' ^'"'^"^^ ^" ^^^ ^^"^- -d<^-- 



th.tTom th 1 T '''"" *^ ^' ^^"^-"-^ known 



hat from the early 'seventies onwards Thomson met 



the ordinary class only twice, and the higher clTss 



be I h""' u r^- "^ "-""'^ --^ -^tSnlv have 

 been himself the strongest objector to any a^ranee 

 -ent that would have cut him off altogether from Ws' 



rrdSe^r-^^- ^'' -'-'- -' ^^ ^^'^ 



w/'k^" J^'""^^''"'' '^^°"^ ''^^""^e begins with 1871 

 an which year Thomson was president of the Britfsh 

 Association at its meeting in Edinburgh. During he 

 ollowing fifteen years or so he was at the height of 

 ^.s activity. His Atlantic cable-laving expeditions 



H k'^ begun the series of yachting excursions 



hth ' T!l'''"'"^ ^"' °*^^'- -Perinfents at sea 

 .hich resulted in the compass and sounding machine 

 ^ jear or two later some further cable-work was 



ZtZlZVu"'' '^"'' '^" introduction into navi- 

 :hkh JJ •-■ '^"''''^ '^""^P"^^ ^"^ the sounder. 



t^\^luTV" T '"'"'" ""' ^°^^- °" hoard 

 essll In^^H . "l^. P^P^'-^^' ^''"•PP^d ^^--going 



Tulnt i ""^ *^" ''^"'^"^ ^^^"d^'-d electrical 



istruments for exact laboratory and workship mea- 

 arements. Afterwards Jr, tu^ » • . ^*'"P ""^a- 

 -era^rp th« -^ ' ^^ 'nineties, came the 



-erage the presidency of the Roval Society and the 

 ever-to-be-forgotten jubilee celebration in " x'sg" 



Zi^ .t /" ?^^' "■°''''' ^"^^ theoretical and 

 actcal extending from 1857 to 1874, and of his 

 any other practical activities. Prof Thompson's 

 >ok contains an admirable account. It is wrTtLn in 



non nT?'- *^^' ^"^'"^^^ ^^^'^'■^'" non-niathematical 

 no.ph>sical. can^read^it with interest a.d enjoy- 



65 



meat. No such person can lay down the second 

 vohame without a feeling of amazement that so much 

 achievement in high regions of scientific discovery 

 and invention could be crowded into one life, even 

 though that extended far beyond the Psalmist's 

 three score years and ten. Indeed, the book may do 

 much good by telling the pubUc at large how mucht 

 IS indebted for its safety in travelling, for telegraphic 

 communication from continent to cfminent and '^! 

 t^een the old world and the new. and for many other 



knnl. V'". ''^ ""'^^^ ^^ '^^ advancement of natura 

 knowledge), to patient investigation carried on bv 



a^ist^^'ts. '"' '^^ ^°^^ °^ ^^"""^ ^^"^-^^ -^ 

 There are a few corrections here and there that we 

 should like to see made in a new edition, but these 

 are not of any great consequence, and need not be 

 here enumerated. We have come to the end of the 

 space aUotted to this review, and only a few points 

 here and there have been touched upon. The throng- 

 ing memories of the past suggest innumerable topics 

 on which we might dwell. All around are memorials 

 of the great man who has passed away and the work 

 he carried through. But it is better to forbear and 

 ma last word to commend Prof. Thompson's book to 

 all who care to know something of the life and the 

 victories of a leader of the armies of peace. 



A. Gray. 



D VNAMIC ELECTRICITY, 

 Electricity. By H, M. Hobart. Pp. xix4-2o- 

 (London ; Constable and Co., Ltd.. 1909.) Price 65' 

 net. 



T N this book the author attempts to impart to the 

 reader a fundamental knowledge of dynamic 

 e-lectricity without using mathematics, or rather with- 

 out giving mathematical proofs of his statements 

 He evidently believes in the possibility of such study 

 for in the preface he says that 



"Without any accompanying study of other text-books 

 almost anyone who is in earnest can make ^ood 

 progress in acquiring a fundamental knowledge of the 

 tr"eatTse.'- "^^^"''>' ^>' ^ ^^'^^^^^ ^tudy of thf present 



Now this is rather an ambitious statement, but if 

 the author had followed the orthodox method of using 

 mathematics in elucidation of experiment he might 

 have succeeded. He has, however, deliberately di«;. 

 carded the use of the most elficient tool we have in the 

 interpretation of experimental results, and thus the 

 task of the reader is made more difficult, and not more 

 easy, as he hoped to make it. The author cannot do 

 entirely without mathematics, or at least without ex- 

 pressing certain relations by mathematical formula 

 but he gives these without showing how thev are 

 obtained, merely as statements without proof. 'Here 

 are a few examples : on p. 59 we are told that a 

 circular conductor i cm. long, and canning 10 

 amperes, acts on a unit pole in the centre of the 

 circle with a force of i dyne. No proof is given for 

 this statement, yet, starting from this, the author 

 develops, also without mathematical proof, the law 

 that the magnetic field round an infinite strkigfat con- 



