Objects, and on the Oscillating Electric Spark, 251 



anxious to obtain photographs of these forms which should 

 be as sharp and as clear as the photographs already described. 



Fig. 2. 



Mr. Chichester Bell described to me in a letter a method 

 which he had used successfully for this purpose, which is 

 more especially interesting now, as Lord Rayleigh has recently 

 exhibited photographs taken by a very similar method. Mr. 

 Chichester Bell simply makes a small spark with one or two 

 Leyden jars several feet away from the plate. The jet of 

 water is allowed to fall between the spark and the plate, but 

 as close to the plate as possible. The shadow cast under 

 these conditions is perfectly sharp and will stand considerable 

 magnification, and the light is quite sufficient to blacken the 

 plate except when the water-drop protects it. Fig. 3 is an 



