IO 



NA TURE 



{Nov. 6, 1879 



possess any knowledge of the subject. We are not 

 disposed to be critical on a work published with such 

 evidently good intentions. The physiological portions of 

 the text are good, and if thoroughly taught to students 

 and understood by them will place them far above the 

 ordinary standpoint of the medical student of the day. 

 The more purely anatomical descriptions would have been 

 improved if written more for the plates than they have 

 been. The plates themselves will be found extremely 

 useful. We should have preferred that the amount of 

 enlargement of the figures was always given ; structures 

 also like those figured at A on Plate xxiv. should be 

 clearly defined as only diagrammatic representations, and a 

 little greater attention to correctness of outline might 

 fairly have been bestowed on the figures representing 

 parts of the skeleton. The letterpress is accompanied by 

 a pretty copious index to the plates, which might even 

 still with advantage be greatly enlarged. This book in 

 the hands of an intelligent teacher will be found most 

 useful and instructive, and it may be made the text from 

 which to preach many a most important practical lesson. 

 Take the short paragraph headed Salivary Glands, how 

 much human suffering might be avoided by a right com- 

 prehension of the facts therein stated. 



Electric Transmission of Power. By Paget Higgs, LL.D., 



D.Sc. (London: E. and F. N. Spon, 1879.) 

 One of the important practical questions which an 

 engineer continually has to face is the transmission of 

 power from the place where the power is generated to the 

 spot where the power is needed. Where the distance is 

 great, belts and shafting are not only wasteful but imprac- 

 ticable, and hydraulic or pneumatic transmission is called 

 into play. Here, again, great distances cannot be sur- 

 mounted without great loss of power, and hence from time 

 to time many wistful glances have been turned in the 

 direction of electricity. It is only to-day, however, that, 

 amid the manifold applications of electricity, its employ- 

 ment as an economical means of transmitting power has 

 become a question of practical importance. 



At the Loan Collection of Scientific Apparatus exhibited 

 at South Kensington in 1876, two small magneto-electric 

 machines made by Gramme were to be seen illustrating 

 this electric transmission of power. The mechanical 

 work expended in one machine was converted into 

 electricity, conducted over a considerable space, and 

 transformed again into mechanical work by the other 

 machine. The amount of power practically reclaim- 

 able by such an arrangement, as shown by recent ex- 

 periments quoted in the little work before us, " may 

 amount to 48 per cent, of that expended in the first 

 instance. This amount of reclaimed power is indubitably 

 superior to that obtained with compressed air, and 

 approaches the practical efficiency of hydraulic transmis- 

 sion" (p. 85). With great distances the relative efficiency 

 of electric transmission must be still more marked, besides 

 the advantage that the conductor, having nothing to burst 

 or give way, can be led in any direction or freely moved 

 whilst transmitting many horse-power. Already in France 

 ploughing has been done by electricity with advantage, 

 and where natural sources of power, as waterfalls or tidal 

 action, exist in any neighbourhood, the extreme value to 

 a community of this novel application of electricity is 

 sufficiently obvious. Municipal authorities might find in 

 the water supply of a town an unexpected source of in- 

 come. For where there is a continuous supply of water 

 under considerable pressure, as is the case in an increasing 

 number of our large towns, baths and washhouses might 

 be erected in the lower parts of the town, and the energy 

 possessed by the water converted into electricity and dis- 

 tributed for sale as power, whilst the matter of the water 

 would of course remain equally serviceable for the pur- 

 poses intended. 



To those interested in the general question of the 

 electric transmission of power we do not know any better 



guide than Prof. Ayrton's admirable lecture on this subject 

 before the British Association. To the student the work 

 before us will be found useful for more extended reference, 

 as it gives the salient features of the investigations by 

 Mascart, Hopkinson, Siemens, Houston and Thomson, 

 and others, on the efficiency of various dynamo-electric 

 machines. But we regret that Dr. Higgs has issued this 

 book with such precipitate haste, for, as it stands, it is a 

 most slovenly piece of patchwork, and to be of real use to 

 the public it must be in part rewritten and the facts 

 presented in a more intelligible and orderly sequence. 



W. F. B. 



LETTERS TO THE EDITOR 

 [Tne Editor does not hold himself responsible for opinions expressed 

 by his correspondents. Neither can he undertake to return, or 

 to correspond with the writers of, rejected manuscripts. No 

 notice is taken of anonymous communications. 

 [The Editor urgently requests correspondents to keep their letters as 

 short as possible. The pressure on his space is so great that it 

 is impossible otherwise to ensure the appearance even of com- 

 munications containing interesting and novel facts, ,] 



Sun-Spots in Earnest 



The communications in Nature, vol. xx. p. 625, regarding 

 the note of Prof. Piazzi Smyth, Nature, vol. xx. p. 602, 

 induce me to send an extract from my observing-book on those 

 spots, together with some observations of them by Ilerr 

 Hartwig, assistant to the observatory. 



My observations of the sun are made with a rather small tele- 

 scope, aperture of object-glass by Reinfelder and Hertel, of 

 Munich, 74mm., with Merz polarisation eye-piece, power 55, 

 images very fine, colourless. 



1879. M.T. Strassb. 



October 6 ... o o No spot on the sun. 



,, 7 ... o 10 On the following limb two great 



regions of faculce, with extremely 



narrow black spots in them. 



,, 8 ...10 The group of faculx, seen yesterday, 



contains to-day three great spots, 



with double nuclei ; besides that 



there is a fourth system of three or 



four smaller spots with penumbra. 



I did not look at the sun on the following days. The 



observations of Heir Hartwig are made by projection and with 



the heliometer of the observatory. By this instrument the polar 



and equatorial diameter of the sun has been measured every day 



since April, 1876, clouds permitting. It was during this series 



of micrometric measurements that Herr Hartwig made his 



remarks. 



Sid. T. Strassb. 

 October 6-7 ... 12 53 The sun appears without spots. 



„ 7-8 ... 12 25 Sun without spots; very bad defini- 

 tion. 

 ,, 8-9 ... 12 10 Beautiful group of spots near the 



following limb. 

 ,, IO-II ... 12 15 Same group of spots, as seen the day 

 before yesterday. Four very great 

 spots ; the following, which had two 

 nuclei, like the others, has to-day 

 three. 

 „ 12-13 ••• J 3 IO Double spot on the middle of the 

 disk ; group of spots on the follow- 

 ing limb. 

 Afterwards the clouds did not permit the sun to be seen for 

 a week. It appeal's from these observations, that this first 

 great display of solar activity after the minimum of spots, 

 entered the disk October 6-7 ; it passed off, as Mr. Christie 

 remark?, October 21. A. WlNNECKE 



Strassburg Observatory 



Subject-Indexes 



Most of those engaged in scientific work will probably agree 

 with the views on this subject put forth by Mr. Wheatley in 

 Nature, vol. xx. p. 627. There can be little doubt that a 

 complete subject-index of scientific literature, in the sense in 

 which it is generally understood, could not be compiled, ant 

 that the result of an attempt to do so would be as useless as it 



