244 



Prof, von Kohell upon Galvanography. 



of copper are required, and about seventeen and one quarter 

 ounces of zinc are converted into the sulphate. 



Description of the Apparatus, with figures. 



Fig. 1. Tamborine with its wooden hoop; the three feet on 

 which it rests are to be cut out in such a manner that the air 

 can escape from beneath the parchment on the apparatus being 

 let down into the fluid. 



Fig. 1. 



Fig. 2. 



Fig. 3. 



Fig. 3 and figure 6. Sugar basins with the bottom cut off, 

 and having parchment or ox bladders stretched across the aper- 

 ture thus made. They are either supported on wire legs, as fig. 2, 

 or rest upon a tripod, hke fig. 3, covered with a non-conducting 

 substance, for instance a coat of melted wax. 



Fig. 5. 



Fig. 4 and figure 5, the copper base-plate upon which the 

 painted plate is laid. 



