ELECTRICITY. 155 



dissolve while others will grow upon the other terminal. 

 The same thing can be done still better by filling the 

 horizontal tank for the vertical attachment with the 

 solution of lead acetate, and then bending a piece of 

 platinum wire or of tin wire around the interior of the 

 tank. Then, on inserting another wire at the centre of 

 the solution, and making connection with two or three 

 cells so as to make the centre wire the negative and the 

 hoop the positive pole, a beautiful growth of metallic 

 crystals will shoot out from the centre and spread out 

 over the entire field. In place of the solution of lead 

 use a strong solution of the bichloride of tin, using a 

 tin hoop in the solution. Crystals of tin will shoot out 

 and appear in great beauty. 



These solutions in the horizontal tank should not be 

 more than an eighth of an inch deep. 



HEATING BY THE CURRENT. 



Make a small coil of platinum wire, and thrust the 

 ends of the wire through the rubber of the tank, as 



Fig. 112. 



shown in the engraving, Fig. 112. Fill the tank with 

 water, and having projected the whole, send the current 



