AiiiisT, 1901.] 



KNOWLEDG E. 



183 



takes very properly .i prominont purt in the course of work. 

 We are afr-.tUl. however, that the book iiieluHes too much for 

 the greiil majority of teelmieal students, ami its price is more 

 th;ui n>nny can afford. But the book will serve as an excellent 

 work of reference in the drawingotKee aud workshop. 



•• Dks(.h.vski."s X.xTiR.vL I'uii.o.'ioi'HV." Part 111. Klectrieitv. 

 Prof. J. U. Kverett. .\t..v., D.C.L.. f.R.s. (Blaekie & Son.) 1901. 

 -Desehanel's work has been a standard stuilents' book for many 

 years through the translation made by Prof. Kverett. In this 

 [wrt. which is devoted to Klectrieily and Magnetism, the amount 

 of prognss t« be ivport<Hl has become so great as to necessitate 

 almost a lomplete rewriting. Many of the old tigures still remain, 

 but the text is very much changed. Attention can be directed 

 to a few of the novelties only. Tlie modern ideas of electrical 

 .u^tion are fully stated ; accounts of practical ternft are given, 

 such as " angle of lead," " charact*"ristic curves," and the like. 

 The usual method of conveying electric: power by polyphase 

 currents: Kwing's magnetic test.s of iron: descriptions of modern 

 giilviUiometers : Hertz's experiments : Poynting's theorem on the 

 propagation of electro-magnetic energy — these references will suffi- 

 ciently demonstrate that the liook is up-todatc. Desclianel's 

 treatise always occupied a special rank of its own. It was not 

 simply a record of discovery more or less furnished with links 

 of "theory": in short it wa,s scientific in spirit. We think in 

 the present edition. Prof. Kverett is to be congratulated on 

 having maintained this position. The rigour of tlie work has 

 not diminished — has not been sacrificed to give a smattering of 

 the things which are newest. It is :» book for study. Used by 

 students who are receiving at the s:ime time a. good practical 

 laboratory course, it will be of great value in keeping the 

 fact before them that a knowledge of electricity does not solely 

 consist in being able to carry out certain measurements. The 

 ;imount of work necessaiy to m;ister the contents of the book is 

 much more than its size would probably indicate. Occasionally 

 the s-tyle seems difficult, but to the earnest student this will 

 be an incentive to close studv. 



^ BOOKS RECEIVED. 



Colloquies of Criticism. (Fisher (iniin.) 3s. 6d. net. 



Two Undiscovered Planets. By G. K. Sntcliffe. (Bombay : 

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Poems. By W. B. Yeats (Fisher Unwin ) 7s, 6d. 



Matriculation Direciorii (The Z/aiversi/t/ Tutorial SeriesJ. .June, 

 1901. (Cambridge; Burlington House. ) ls.net. 



Sculptures of iSanta Lucia Cozumahualpa, Guatemala, in the 

 Ethnological Mil seum of Berlin. By Herman Strebel. (Smithsonian 

 Institution.) 



Poisonous Plants in Field aai (larden. By the Rev. Prof. G. 

 Henslow, ii.A., p L.s., P.o.s., ir. (Society for Pi-omoting CIiri.stian 

 Knowledge.) Illustrated. 2s. td. 



Fifty Years of Catholic Lije and Social Proqres.s. A^ols, 1. and 

 II. By Percy Fitzgerald, il.A., F.s.A. (Fisher t'nwin.) 2Is. 



Microscope and its Revelations By the late WilUain B. Carpenter, 

 c.B,, M.B., LL.D., F.K.s. ReWsed by the Rev. W. H. Dallinger, d.sc, 

 D.C.L., IL.D., F.B.S., &c, (J. & A. Churchill.) Illustrated. 288. 



Zife and LHters of Gilbert White. 2 Vols. Bv Ra.shleigh Holt- 

 White. (Mun'ay.) .•52s. 



Natural Bistory and Antiquities of Selhorne. By G-ilbert White. 

 Edited by L. C. Miall and W. Warde Fowler. (Metliiien k Co.) (is. 



Betrospect of Surgery during the Past Century. By John Poland, 

 F.B.c.s. (Smith Elder.) . ,58. 



Hypnotism and Suggestion in Therapeutics, Eilncation ami 

 Reform. By R. Osgood Mason, A.M., M.D. (Kegan Paul.) G?. 



Journal of the Socieli/ of Comparatioe Legislation. .lime, 

 1901. (Murray.) 5s. 



Cirilian War Hospital. By the Professional Staif, Portland 

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Your Mesmeric Forces and Mow to Develop them. By Frank H. 

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International Art Notes. March, 1901. (Swan Sonnenschcin.) 

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Stalk-eyed Crustacea of British Quiana, West Indies, and 

 Bermuda. By Charles G. Young, M.A., M.D. (Watkins.) 

 125. 6d. net. 



Amphibia and Reptiles. By Hans Gadow, M.A., F.E.S., &c. 

 (ilacmillan.) lUuetrated. ITs. net. 



Bulletins of the Philoiophical Society of Washington. 



Annual Reports of the Bureau of American Ethnology. Seven- 

 teenth (Part 1.— 1895-96). Eiithteenlli (Part I.— 1896-97). 



Catalogue of Plujto ApparatuH. City Sale and Exchange. 93 and 

 94, Fleet Street. 



Astronomical. — We note with rcgicl. tlial, the two 

 photograpiis ul' Nova Pcrsci and siii-rouiiding stars, 

 reproduced in l.ho July imiiibcr, were dated 1900, 

 February 'iO, and 1900, February 28. In each ca,se tlie 

 year should, of course, have been 1901. 



In Circular No. .50, Prof. Pickering gives a sunuiiary 

 of the observations of Nova Pcrsci made at Jlarvard up 

 to May 3, 1901. The characteristics of tlic spectrum 

 prior to March 19 are sufficiently well known to need 

 no further reference here, and the subsecjuent obser- 

 vations may be regarded as confirmatory of those made 

 at Stonyhurst, Kensington, and elsewhere. About 

 March 19, the star became a variable with a ])eriod of 

 from 2 to 5 days, and the general result of the Harvard 

 photographs seems to he that there were wcll-maiked 

 variations of spectrum accompanying the changes of 

 magnitude. On March 27, 30, April 1, 13, and 27, the 

 spectrum was "normal," while on March 19, April 12, 

 26, 28, May 1, and 3, it wa,s "peculiar"; among the 

 chief peculiarities apparently being ihat a green band 

 extending from 4990' to 5040 was greatly intensified, 

 while H t, was either displaced or replaced by a new line 

 with its centre about \ 387.5. The " ]ioculiar " spectrum 

 wa,s associated with a minimum of the star except on 

 April 12. No attempt is made to explain the origin 

 cf the peculiar lines, but it is not improbable that the 

 green band, which was brighter at the minima, was the 

 chief nebular line at A .5007, while the band with its 

 centre about A. 3875 was p(,ssibly identical with a line 

 which is among the brightest in the spcctiuiii of the 

 Orion nebula and certain planetary nebuhe. 



A recent investigation of sun-spot data undi^itakcn by 

 Dr. W. J. Lockyer has led to the conclusion that under- 

 lying the recognised 11-yearly period tlierc is another 

 cycle of about 35 years' duration. This periodicity 

 exhibits itself in the varying intervals between the 

 minima and., succeeding maxima, and in the total spotted 

 area from one 11-yearly period to another. Correspond- 

 ing variations have also been traced in the curves of the 

 terrestrial magnetic elements. A 3.')-ycarly period has 

 been previously found by Briickner in climatic changes, 

 and by Richtcr in the movements of glaciers, while Mr. 

 Egerson has found a period of from 33 to 34 years in 

 the occurrence of rainfall, thunderstorms, and westerly 

 winds in the month of April at Sydney. 



We learn frorir Mr. Maunder that he has been 

 detained at Mauritius, and will not reach England until 

 late in August. On his return, Mr. Maunder will 

 publish in this journal a plate of the' Sun's corona, of 

 which successful photographs have been ditained. — A. F. 



Botanical.— A paper on the longevity of seeds, based 

 on the examination of numerous grains of wheat and 

 barley discovered during recent investigations in Egypt, 

 and dating back upwards of four thousand years, 

 appeared in Vol. 130 of the Cwnpl.i->< Rnidm dt 

 I'icadernie des Sciewes, Fans. The conclusions of the 

 author, Monsieur Gain, are distinctly opposed to those 



