ELKCTUOMOTIVK KOIKES IN THE VOLTAIC CV.\.\.. 



471 



on its ir.iiiilli, 



'J8('. and HO: 



Wlicn lie touches on theory lio agrees with Tlionison. Professor Clifton 

 lias examined the Voltii eifects for the substances ordinarily used in 

 hattcrits with great care, and has probably elicited tlio maximum of 

 iicennicy possible to his method, lie <;ives the K.M.F. of numerous virgin 

 (•(.'lis in which no current has circulated. 



\yit(in and Perry in 187(5 devised in Japan a very ingenious but 

 Miiiicwliat unwieldy modification of Kohlrausch's method, and with the 

 lu'lp of students carried out a most extensive and laborious series of 

 <lcterniinatioiis ol' metal/metal, mefal/li(pnd, and li((nid/liquid contacts.' 



'h;. I — Ayrtoi. ;iiiil I'cii-y's Apparatus for iiicasuriiig tlio Volta eft'ccl with all sorts 



of substances. 



riic -iili.-iiaiicps lire ari-.-ni^ril on the lower iilntforin, n.s, for instance, the metal nnd liquid shown 

 in the linuie at !• imil i.. The ]ilutfiiriii A n is *'ii|>!il>le of rotation throu;;h ISO" on its rail- 

 w.iy c. ;i antl 1 arc faivfully iiisuliitcd kIU i)latL'S li.\t'<l to a bar ■which can l)c raised nnd 

 li'Wertd. The experiment consists in lowering,' these jilates close to the surfaces to bo 

 ti-sted, and connertinjr them with <'ach other for a short time ; then raise them, rotate the 

 jilatt'orm through Iso-^, lower a^•nin. ami connect them with a quadrant electrometer. 



On the appearance of Clifton's paper the year after, they issued a 

 strongly-worded claim - in respect both of priority and completeness, a 

 claim which seems to me well established, for their results are the most 

 comprehensive yet obtained, and the energy needed to devise, construct, 

 and use such an apparatus as the one they depict must have been 

 immense. A convenient summary of their imrabers is to be found in 

 I'lvcrctt's ' Units,' second edition. The main result achieved by them is the 

 experimental establishment of the summation law for all substances 



' Ayrton atid Terry : Drit. Assoc. Glasgow, 187('>. No abstract printed. Part I. 

 I'ruc. Itiiij. Sue. 1877 or 1878 is a preliminary account. Part II. describes a metallic 

 voltaic cell of mairnesium and jjlatinumand mercury, also some experiments on elec- 

 ii'ilytcs of higli resistance. P.'u-t III. P/iil. Trans. 1880, is the complete account 

 of their published eloctroscopic experiments. 



• Ayrton and reny : Letter published in 1877 by Meiklejohn, Yokohama. 



