340 Dr. Draper on the Use of a Secondary Wire as a 



Here we have an exemplification of the converse of the 

 fact ah'eady so much insisted on. As the quantity developed 

 from the sa7ne surface gradually became greater and greater, 

 the tension became less and less, due to the increased con- 

 ducting powers of the fluid medium. It is the same effect 

 that would have been produced by constantly shortening the 

 conecting wire. 



Such is the action of increasing doses of sulphuric acid ; 

 let us now see how nitric acid will act. The copper plate 

 being repolished, and the zinc reamalgamated, and every- 

 thing else being as at the commencement of the former trial, 

 the latter acid was now added to the cell, in the same way 

 that the former had been used. 



Table F. 



These measures are effected with some difficulty as the acid 

 acts somewhat irregularly, and keeps the needle vibrating. 



Muriatic acid, under the same conditions and circum- 

 stances, being substituted, gave as follows : 



Table G. 



NiTROSULPHURic ACID, the Constituents of which were 

 added alternately in equal measures, was next tried. 



