22 Quarterly German Magazine. 



plate constantly retains a fresh surface. To avoid the sulphate 

 of copper from touching the zinc, through which it would be 

 directly decomposed, the space which contains the zinc, is se- 

 parated from that which holds the copper, by a porous parti- 

 tion of burnt clay, or a similar substance, and the space for 

 the zinc is filled with diluted sulphuric acid. The partition 

 hinders the mixture of the two fluids , while it permits the 

 movement of the electricity through its pores. 



In this manner we have a permanent chain ^ the power 

 of which can exist for days together, but as the dilution of I 

 the sulphate of copper continually decomposes, Ave must, from 

 time to time, renew it; and as the sulphuric acid changes 

 gradually into sulphate of zinc, that must also be renewed. 

 The zinc will gradually be quite dissolved, and we learn from 

 that, that we cannot produce the movements of electricity from 

 nothing, but only at the expense of the consumed zinc. From 

 nothing comes nothing. 



Besides this DanieU's chain, there are many other per- 

 manent chains^ of which we antII only name a few. In Grove's 

 chain, platina takes the place of copper, and stands in smoking 

 nitric acid (aqua fortis). Nitric acid forms Hkewise with hy- 

 drogen, water, because it gives it a part of its oxygen, and 

 retains its nitric acid. The tension between zinc and platina 

 is much greater, than that between zinc and copper, the chain 

 is therefore stronger: but the consumption of sulphuric acid 

 is very expensive, and the vapours which it exhales, are very 

 deleterious to metallic objects and to the lungs. As platina 

 is very dear, Bunsen has replaced it by a coal especially pre- 

 pared for that purpose, which works in the same manner as 

 platina. For technical purposes as well as for electro-metall- 

 urgy and telegraphy DanieU's chains are most to be recom- 



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