Chemical Notices : — M, Winkler on Indium. 



443 



Jig*. 2 



of the battery, while the other pole led 

 to the central wire. At the signal 

 end, of course, a similar arrangement 

 (fig. 2). This would give to the in- 

 duced current the same propelling force 

 as the primary, and utilize the half of 

 the power of the battery that is now lost 

 by putting to earth. That putting to 

 earth is discharge of half the force of the 

 current is an obvious deduction from 

 theory (see Phil. Mag. for March 1865), 

 but it has also been experimentally 

 proved by Wheatstone (Atlantic Cable 

 Report, p. 292, Exp. 5). At p. 103, 

 § 30, Atlantic Cable Report, a similar 

 arrangement to fig. 2 is suggested by 

 Mr. C. V. Walker; but the necessity of 

 having the outside and inside conductor 

 of the same metal — the vital point in 

 my opinion — is not insisted upon. This 

 arrangement would exclude earth-cur- 

 rents (§§21, 25, p. 102, Atlantic Cable 

 Report) ; and if the signal-house, as well 

 as the shore end of the cable, be iron- 

 covered, it is difficult to see how atmo- 

 spheric electricity could intrude upon 

 the signals. 



, There are other considerations with 

 respect to conduction that press upon 

 the attention as suggested by theore- 

 tical considerations, but it would be 

 presuming too much to expect they would receive attention be- 

 fore the fundamental point of surface conduction has been ex- 

 perimentally established. 

 Inverness, November 20, 1865. 



LXV. Chemical Notices from Foreign Journals. 

 By E. Atkinson, Ph.D., F.C.S. 



[Continued from p. 363.] 



WINKLER has communicated* a series of observations on 

 indium. Hitherto the Freiberg zincblende has been the 

 only material generally accessible ; the zinc from this source is 



* Journ.filr Prdkt. Chemie, xciv.l. Zeitschrift fur Chemie, vol. i. p.228. 



