3o6 



POPULAR SCIENCE MONTHL} . 



complete nowadays unless it contains a complete set of photo- 

 graphic apparatus. 



These are but a few among the many things that photography 

 does for us. Each year reveals some fresh uses to which it can 

 be placed. 



Quite recently the electrician has discovered its value to him 

 in many ways, principally in registering electrical discharges, so 

 that the same may be carefully studied at leisure. At a meeting 

 of the British Association in 1892, Mr. A. A. Campbell Swinton 

 showed some most interesting photographs of electrical discharges 

 which are here reproduced (Figs. 1 and 2). According to an ac- 

 count of them given in the Electrical Review, these figures were 



Fig. 1. — A 1'ositive ])isi;uarge. 



all obtained without the employment of a camera or lens, but 

 produced by merely causing tlie electrical discharges to take place 

 across the sensitive surface of an ordinary photographic dry 



