14G Pictures Produced on Photographic Plates in the Dork. [May 5, 



site page, which had been in contact with the one which was used ; 

 thus this ghostly effect was produced. 



I believe, ttien, that it is this active body, hydrogen peroxide, 

 which enables us to produce pictures on a photographic plate in the 

 dark. There are many other curious and interesting effects which it 

 can produce, and which I should like to have shown you, had time 

 permitted. 



I would only add that this investigation has been carried on in 

 the Davy Faraday Laboratory of this Institution. 



[W. J. E.] 



