114 



GALVANIC ELECTRICITY. 



273. DIFFERENT KINDS OF BATTERIES. 



What is said . .. . 



o/ the differ- There are different kinds 01 galvanic bat- 

 britertef teries, but the principle in all is the same. 

 Two of the forms in most common use 

 are described in the Appendix. Smee's battery is 

 especially recommended to the student, for its cheap- 

 ness, simplicity, and efficiency. It is very similar, as 

 will be seen, to the simple one which has been already 

 described. 



274. COMPOUND CIRCUIT. For the sake 



What is said f . ,. . . f 



of the com- ot simplicity, all the foregoing decomposi- 

 pound circuit? tions have been described, as a result of the 

 action of a simple voltaic circle, consisting of an acid, 

 and two metals. But, it is found that in many decom- 

 positions, the power of such a battery is insufficient. 

 The efficiency is increased by employing several single 

 batteries together, and bringing them all to bear upon 

 the same electrode. 



How are heat- 275. The heating and magnetic effects 

 ing and mag- f fa b attery are very ^cft increased by 



netic effects J J J 



produced? uniting the plates, as in the preceding fig- 

 ure, where all the zinc plates are joined together, so as 

 virtually to form one. The quantity of the current is 

 thus increased. Power of decomposition, and to give 

 shocks, such as are taken from an electrical machine, 



