January 25, 1895.] 



SCIENCE. 



1U9 



Blondlot (C. E., 117, p. 543; 1893). The sig- 

 nals were sent over a wire of about one kilo- 

 meter in lengtli and another of about 1.8 

 kilometers. In the fii-.st ease the mean ve- 

 locity was found equal to 293,000 and in the 

 second to 298,000 kilometers per second 

 which is very close to the velocity of light. 

 Poincar6 proceeds now to the discussion of 

 tlie most severe test of the Maxwellian the- 

 ory, that is the propagation of electromag- 

 netic waves through dielectrics. 



M. I. rupix. 

 Columbia College. 



[To he Ciiiidudcd.) 



Model Engine Comtnidion. — J. Alexander. 

 — New York and London, Whitaker & 

 Co. 1894. Illustrated by 21 sheets of 

 drawings and 59 engravings in the text. 

 12mo. pp. viii + 324. Price, 83.00. 

 This little book is an excellent treatise on 

 the construction of models of stationary 

 locomotive and marine engines, and con- 

 tains also instructions for building one 

 form of hot-air engine. It is written by an 

 author evidently familiar with his subject, 

 and the text and illustrations are such as 

 will serve the purpose of both artificer and 

 amateur, desiriug to produce model repre- 

 sentations of real working engines of stand- 

 ard forms. Bright young mechanics will 

 find here business-like statements of details 

 of drawing, pattern-making, and finishing 

 such models ; and, if heedfully complied 

 with, these instructions will result in the 

 production of steam-engines wliich will actu- 

 ally ' steam,' and which will delight the 

 lieart of the meehanician. The drawings 

 are all representative of British practice, 

 and, in some respects, therefore, quite dif- 

 ferent from familiar jiraetice in the United 

 States; but British jiractice is 'not so bad," 

 after all, and many old mechanics, and prob- 

 ably every amateur, will be able to profit 

 greatly by the careful study of this little 

 work.' R. H. T. 



NOTES. 



PERSONAL. 



Karl Hansiiofer, Professor in the Uni- 

 vei-sity of Munich, and w^ell known through 

 his researehi's in crvstallogi'aphy and other 

 branches of mineralogy, lias died at Munich 

 at the age of fiftj'-four. 



Prof. G. Lewitzky has been appointed 

 Director of the Observatory in Dorpat, and 

 Dr. L. Sturve succeeds Professor Lewitzky 

 at Charkow. 



Prof. F. KoHLRArscu,of Strassburg, was 

 proposed as the successor of Hei-tz at Ber- 

 lin, but the death of Ilelmholtz interven- 

 ing he will now succeed the latter in the 

 Directorship of the Physico-Technical In- 

 stitute. 



gexer.vl. 



The discontinuation of the Index Medicus 

 is threatened unless sufficient subscriptions 

 are secured before February 1 to defray the 

 costs of publication. 



AccoRDiNcj to the I'iibU.ilier:<' Cireuhir there 

 \vere 5,300 new books and 1,185 new editions 

 published in Great Britain during 1895, 203 

 more than during isfl4. Of these, 98 new 

 books and :!() new editions are placed under 

 the beading ' Ai-ts, Sciences and Illustrated 

 Works.' 



Mr. (teorge F. KiNZ, Special Agent, Di- 

 vision of ^Mining Statistics and Technology, 

 U. S. Geological Survey, has .sent letters ask- 

 ing for imformation concerning the fresh- 

 water pearl fisheries, and concerning pre- 

 cious and ornamental stones of the United 

 States. 



Prof. S. P. Lanciley, Secretary of the 

 Smithsonian Institution, has addressed a 

 letter to the competitors for the Ilodgkins 

 Fund Prizes of 810,000, of 82,000, and of 

 81,000, stating that in view of the very 

 large number of competitors, of the delay 

 which will be nece.s.sarily caused by the in- 

 tended careful examination, and of tiie 

 futber time which may be required to con- 



