I. BATTERIES. 26 1 



1249 a. Volta Faradaic Machine, with arrangement for 

 taking in the pocket ; also giving interrupted or continuous 

 current, the batteries being of the constant Leclanche form. 



Harvey, Reynolds, and Co. 



1249b. Combined Holtz' and Bertch's Induction Ma- 

 chine, with arrangement for separating the same. 



Harvey, Reynolds, and Co. 



1249c. Induction Electric Machine. J. Teller, Munchen. 



1249d. Toepler's Induction Machine. 



Royal Institution of Great Britain. 



The apertures usual in the fixed disc are here dispensed with as unnecessary, 

 the disc is thus rendered less breakable, and a greater action is obtained. 

 The apparatus is very simple in construction and can easily be taken asunder 

 for cleaning. The driving disc is at the same time utilised as the exciter of 

 electricity. 



1250. Holtz's Electric Machine, with fixed induction 

 surface. Borchardt, Hanover. 



1251. Holtz's Electric Machine, with movable induction 

 surfaces. Borchardt, Hanover. 



1252. Machine for exciting Positive and Negative Elec- 

 tricity. E. Stohrer, Leipzig. 



It has the form of a small disc electric machine. According as you take 

 hold of the one or the other brass ball at the end of the caoutchouc frame 

 you obtain a quantity of positive or negative electricity sufficient for various 

 experiments with electro-dynamic and charging apparatus. The apparatus- 

 is also recommended for excitation of induction machines. 



b. GALVANIC BATTERIES. 



1253. Water Battery. 



Museum of Physical Apparatus, King's College. 



1254. Daniel!' s Battery, employed in researches by Pro- 

 fessor Daniell. Museum of Physical Apparatus, King's College., 



1255. Early Voltaic Batteries : 



Babington's battery. 

 Cruikshank's 

 Wollaston's 

 Sturgeon's 

 Museum of King George III., King's College, London. 



1256. Hare's Calorimotor, or Deflagrator. 



Museum of King George IIL, King's College, London. 



1257. De la Rue's Powder Chloride of Silver Battery. 



Tisley and Spiller. 



