46 



DESCRIPTION OF GALVANIC BATTERIES. 



battery (fig. 17); figs. 22 and 23 are used for Daniell's battery; the 

 latter for connection with a zinc rod, the former to bind plates 

 together. In all cases, the parts that touch the surfaces to be con- 

 nected must be perfectly clear and bright. 



In many cases, when a complicated apparatus has been put to- 

 gether, it is desirable to ascertain whether the connections are all 

 perfect. This is best determined by means of a galvanometer, two 

 varieties of which are represented by figs. 27 and 28. 



