S. p. Sharpies on some fornis of the Galvanic Battery. 249 



The first measurements, made in March, 1870, ^vere merely 



to determine tlie electro-motive force. In tlie rest of tlie experi- 



: ( ills, made in December, 1870, and Jan. 1871, the internal 



■<'s were also determined. 



''./mment. For purposes of com]):iri-()ii. .■ \)-aw< ""- rdl 



■1 up, using the same zinc and iK)n>ii- ( 1.).. ;i'i.i tln'snne 



_: liquid, but substituting for the <.'ar1i<)ii a ii.>li.>u (■\,iii- 



"pper open at one side and using a -,it..r;n<"i -i'Iii;l,.ii ol' 



,11 ;• sulphate as the absorbing liquid. The moan ot >ix (-(^m- 



I'unsou?; ot tliis with a Bunsen's cell gave 169 tor th(> oU^'tro- 



; lotive force of the latter, that of Daniclhs being lOO. Latimer 



• "lurk" gives the number 175. 



Kr. Xo. 2. The porous cell was lilk^l witli a situral.-/i -..bi- 



.!iM sulphuric acids, diluted with^our tinu- 'tL,.ir \ul,M.irof 

 ■■":ti''r. This gave a constant batterv w(>rkin,u without .-i\ing 

 "tr add fumes until the exciting Hquid was rxhau^lcl. Its 

 electro-motive force was the same as that of the or^linarv Bun- 

 sen cell. 



Ex. No. 3. The porous cell was filled with coarse fragments 

 of potassic bichromate, and then saturated with nitric acid. 

 The electro-motive force was the same as in the last experiment, 

 hilt the battery was not quiet so constant, and thei-e was a gi-eat 

 ^vaste of bichromate, there being much more than was rcquii^ite 

 to saturate the nitric acid. 



^x. No. 4. The cell was filled as in the last experiment, only 

 the liquid used was a mixture of equal parts, nitric and sul- 

 phuric acids. The electro-motive force was the same, but 

 trouble was experienced from the formation of crystals of chro- 

 mic alum which encrusted the carbons and porous cells and 

 stMin.P,! tlie working of the battery. 



A". 5. The absorbing liquid was a saturated solution of 



l»ichromate in hydi-ochloric acid. The electro-motive 



this battery rapidly declined; starting with the same 



^ Bunsen's, in the course of 2i hours it ran down to two- 



'"HMs of that force ; its internal resistance at the start was 1-7 



tiiHt of Bunsen's ; at the end of 2i hours it was 3-6. It gave 



on chlorine during the whole time it was in action. 



Ex. No. 6. The absorbing liquid was a saturated solution ot 

 potassic bichromate in nitric acid. It gave the same electro- 

 motive power as the ordinary Bunsen cell, but the internal 

 resistance was about 2-3 as much. The battery was sensibly 

 constant for twelve hours. 



. Ex. No. 7. Ex. No. 1 was .„^ 



circumstances. The saturated solution 

 t experiment, was mixed with 



the last 



^0. 7. Ex.Yo7i was repeated under shghtly different 

 of bichromate, used m 



