2l8 



NA TUBE 



[July 4, 1907 



be modern, but are certainly not good practice. The 

 autlior's explanation why field magnets are laminated 

 is novel, and, moreover, so peculiar that it merits 

 verbal quotation. He says : — 



" The field cores are often laminated throughout to 

 prevent eddv currents due to any swinging of the field 

 caused by armature reaction, and this often loads to 

 special methods of support." 



Had he said that magnets must be laminated 

 if the stator slots are wide and open, he would 

 have been right, but the explanation he gives is quite 

 beside the marlc. Equally misleading is his indis- 

 criminate recommendation of damping coils as a cure 

 for hunting. .As he mentions these coils just after 

 saying that hunting is especially the fault of gas- 

 engine driven machines, the reader is led to conclude 

 that the damping coils would be especially useful in 

 such cases, whereas every expert knows that damping 

 coils are absolutely harmful if applied to an alternator 

 driven by a gas engine. Gisbert Kapp. 



STOKES'S SCIENTIFIC CAREER AND 

 INFLUENCE. 



Memoir and Scientific Correspondence of the late Sir 

 George Gabriel Stokes, Bart., Past Pres.R.S. 

 Selected and arranged by Prof. Joseph Larmor, 

 Sec.R.S. Vol. i., pp. iv + 475; vol. ii., pp. vi + 507. 

 <CaTnbridge : The University Press, 1907.) Price 

 24^. net, two volumes. 



IT is well known that the record of Stokes's work, 

 splendid as it is, which is contained in the five 

 volumes of his collected papers is far from being a 

 complete representation of the services which during 

 a long life he rendered to science. From his first official 

 connection with the Royal Society in 1854 the tide of 

 production began somewhat to slacken, and after 

 1868, it may almost be said, no sustained piece of 

 work of first-rate magnitude appeared under his name, 

 although shorter papers, often of great value, and all 

 ■showing the impress of the master-hand, were given 

 out from time to time. His energies did not relax, 

 ■and his powers never showed any sign of decay, but 

 they were diverted into somewhat different channels. 

 Partly owing to the rigorous sense in which he con- 

 strued the duties of his various official positions, and 

 partiv in consequence of his own inexhaustible good 

 nature, he was constantly occupied in examining, 

 advising upon, and assisting in the work of others. 

 This gradual change in the manner of his work 

 has been often wondered at, and sometimes de- 

 plored, but it came about quite consistently. There 

 'is a certain type of professional savant to whom sys- 

 tematic production, or at all events publication, 

 with due form and circumstance, is as the breath 

 ■of his nostrils; it must be maintained at all 

 liazards. With this type Stokes had never any 

 affinity. He took to mathematical physics, in the first 

 instance, because his interests and his powers lay that 

 way, and he published the results of his investigations, 

 when they seemed valuable enough, as a matter of 

 course ; but when other duties came which had, as he 

 thought, a more immediate claim, he turned to them 

 NO. 1966, VOL. 76] 



without a moment's regret at the diminished oppor- 

 tunities of personal achievement which they involved. 



For a complete memorial it was therefore essential 

 that some presentation should be made of this im- 

 portant phase of his work. As Prof. Larmor ex- 

 plains, in the preface to the two volumes now before 

 us, the material in the shape of letters is abundant ; 

 but it is naturally very varied in character, and 

 often fragmentary, and much of it was from one 

 cause or another difficult to turn to account. The 

 labour of sifting and arranging the correspondence 

 must have been enormous, and appears to have been 

 aggravated by the circumstance of fresh letters con- 

 tinually coming to hand during the printing. 



The material finally selected has been dealt with as 

 follows. In "Section H." we have an outline of 

 Stokes's general scientific career, illustrated by a 

 chronological series of letters, which touch upon the 

 v-.rious topics which at different stages attracted his 

 attention. " Section HI. A " contains " special scien- 

 tific correspondence " with his father-in-law. Dr. R. 

 Robinson, Prof. Cayley, and Sir J. Norman Lockyer. 

 These letters contain matter which is, in different 

 ways, of great interest ; the letters to Dr. Robinson 

 are specially valuable, as they preserve many interest- 

 ing notes and explanations which would otherwise 

 have been lost. The second volume continues " Sec- 

 tion ni.," and includes letters to and from Maxwell, 

 Joule, Rayleigh. Reynolds, Froude, .\iry, and others, 

 nearly all bearing on scientific work of the first order 

 actually in progress. It would be hopeless, and use- 

 less, to attempt an enumeration of the various 

 points touched upon ; but it is of interest to note with 

 what zest Stakes turns, again and again, to the early 

 objects of his scientific affections, such as the be- 

 haviour of sea-waves, the theory of the pendulum, and 

 the varied problems of physical optics. The collection 

 is 'most of all valuable in that we are allowed a 

 glimpse into the workshop of the master. The most 

 expert craftsman will find much to admire, w-hils^ 

 the novice may derive suggestion and encourage- 

 ment, more perhaps than from the contemplation of 

 the finished worii, which is often apt to beget rather 

 feelings of despair. 



These volumes include also matter of a more formal 

 biographical character. The introductory memoir by 

 Mrs. Lawrence Humphry is a most attractive per- 

 sonal record, written with admirable tact and sin- 

 cerity. To this are appended " apureciations " by inti- 

 mate personal friends, Prof. Liveing, Sir .Michael Foster, 

 Sir William Huggins, and the Bishop of Bristol. 

 Considerable space is devoted to the Jubilee celebra- 

 tion of iSgg, and to the proceedings at the unveiling 

 of the Westminster Abbey memorial. Both these 

 occasions greatly impressed those who liad the privi- 

 lege of attending them, and the record will be highly 

 valued. 



.■Ml who are interested in Stokes and his work, in 

 other words, the whole company of followers of phy- 

 sical science, will feel a deep debt of gr.-ititude to Prof. 

 Larmor for the devoted labour which he has expended 

 on this memorial of his great predecessor. It appears, 

 indeed, that our obligations to him are not yet ex- 

 hausted. The reader of this notice will have remarked 



