EI-ECTKOMOTIVr, FOIICKS IN TIIK VOLTAK; CKI.I.. 



4H3 



int mctiils 

 rroundinj; 



Itzc-Ik'rt:* 



:;»iiicik' tilt 

 cieiit pains 

 s. It ia t)t 



of tllO twn 



)otcntiivl "1 



I by Dr. W. 

 jct, and de- 

 i apparat\H 

 o become it 

 refers with 

 )S0 ima'^inc- 

 Pellat's I'H' 

 of a sort ot 

 llaukel flt'C- 

 ver, a lavLiv 

 13 powdered 

 ,s of cavl)on, 

 roxidc,' ivon 

 id in vavions 

 t it does unt 



IVolta efVocK 



ati(mti)t'.ii' 

 icn made l\v 



10 true, au'l 

 ctric civcuit." 

 lis view, anil 

 ,iiig a theory 



victoriouslv 

 ur of a chemi- 

 )Ocause of the 

 xner (such as 



of the vague 



.il)7.i;4. 



Tl'UblUi-, 



wliiehalmtt-rv 



tlu'V sill'' "' ""' 

 X iiro, iTinl liv ■■• 

 icitviUnMw' 

 c :i satisfactovy 



-, ulcntisdi im> 

 ilso J'o'JIh ''""• 

 ■rio data. 

 Incv's woikH, 15 ■> 

 JK.KMcr seems n- 

 Js (Icstroyeil "> 

 Is Uie trouble i" 

 150), and t""'^ 



and nnsatisfactory viow.s of physicists in j^onoral on tho matter (> j., of 

 Hart) ; bnt I am bound to say that, so fur as I can judfjfe. Dr. von Zalin's 

 own ('xperinu'n(.s are not of that conelusive and decided character that 

 one had hoped for from his start, and lie sifjfiially fails tosnm np tho facts 

 in a neat and crisp muniior. lie adhenvs to tho ctmtact view, bnt his 

 adhe.*iou scarcely seems to mo to be based on strong evidence; and in fact 



Ftc. 11. --Von Zalm'.s Aiqianitiis for c.xpoiiiiientiiig in ilitVereiil (luncs ;it different 

 I'reysari'S and Ti nipcraturi'S, and also in lii^h Vacua. 



The iiiipeT iilatc M is atlaclicd In- Kins'* roils to a slodi^e ii, wliich slides on vortical steel rods 

 <i, lieinK iiuUed up liy a strinj^. On reachin:;' its liii^liost point it conies into contiict with 

 iin insulated iilatinuni wire s. which I'onnnunic'atos witli .a ll.ankul elcctroinetir throii.nh 

 one ot the insulati-tl exits i:. Tiic bottom plate; is supported on the rin^' k. 'v is the .stop- 

 cock for e.xhaustion and elianj;e of f;as. i'ij;-. '2 sliows file appendaf;e to tlie boituin plate 

 t'nr warniiuf;' it l)y a current of steam. J'if;. .'! sliows tho apparatus used lor liif^h vacua. 

 The two ])lates are zinc and platimnn, and the platinum is arranj,fed to fall by its own 

 wcifiht when the wliole thini; is inverted. Tiie diagram shows it in its highest position, 

 and just ii-oiin; to fall l)acU into its dotted position. The frietio)i of its guide rod seems 

 Hot M-holly satistactory. 



liis theoretical views seem a little superficial, considering tho date atwliicli 

 he writes, so that one may admit pretty well idl ho says about contact 

 and not chemical action as the causio of tho Volta effect without being 

 deeply committed to any .specially true or specially false position.' His 



1 lie thermoelectric power ot luetnls tho same Jit one-niillionth atmosphere ;is at 1. 

 This, however, is not conclusive, if it be regarded as a matter ncedina: experiment t{> 

 settle. 



' I am afraid thi."? ;s not peculiar to Dr, von Zahn. It may be that the German 

 writers on the .subject arc too busy accunuilating facts to aire much about their pre- 

 I'ise theoretical bearinpr, but I notice a very loose and unsatLsfactory way of pnttinsr 

 lOrward secondary matters, as if they were the real point.s at i.'^sue, and of never really 



112 



