‘74 M. C. Lea on the Action of Ozone upon 
Art. XI—On the Action of Ozone upon Insensitive Iodid and 
Bromid of Silver; by M. Carey Lea, Philadelphia, 
A STATEMENT has recently appeared in the French scie 
Journal Les Mondes, from which it has been copied,’ to the 
that ozone is capable of giving sensitiveness to insensitive 
of silver. Mr. J. P. Kaiser states that he has found that certall 
vapors, such as the vapor of benzine, exercise a powerful eflet 
of this kind, converting one insensitive variety into one 1a 
was highly sensitive: that he attributed this effect to the ozons 
produce y the contact of this vapor with atmospheric alt= 
that he therefore experimented with air ozonized by a galvallt 
induction apparatus, and found the same results produced, bil 
i 1 more marke gree, a 
This statement was not altogether the first suggestion of the 
once have become practical. For plates could be coated ¥ 
insensitive iodid of silver in ordinary light, (say, for exam 
be placed m® 
ordinary dark slide; and a vessel containing the means of get 
erating ozone could be placed in the camera. On withdraws 
wey 
Nov. 1864, in which s. * tography, 1864, is 392. Also Phot. Mit 
