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preparations which I have found to work well together both 
summer and winter. 
SILVER Baru. 
Pure crystallized Silver Nitrate, 2 ounces. 
Distilled Water, pee He 
Or of the strength of 40 grains to the ounce. 
A plate as large as the bath will hold is coated with 
Collodion, as described below, and left to stand in the bath 
for about half an hour. By this means it becomes partially 
saturated with Iodide and Bromide, and is less liable to fog 
than if used directly without this precaution. Lastly make 
just acid with Hydrogen Nitrate (Nitric acid.) 
Topo-BROMIZED COLLODION. 
Washed Ether, sp. gr. °720 3 ounces. 
Alcohol, sp. gr. *805 Pe x 
Gun Cotton, 16 grains. 
Cadmium Iodide, in powder. er) ar 
Cadmium Bromide 3 arn 
The eun cotton is first placed with the salts in a bottle, 
and the alcohol introduced and agitated until the salts are 
dissolved, then the ether is added and the whole allowed to 
stand until complete solution has taken place. Then the 
clear collodion poured off and preserved for use. 
For development, I have used both Iron solutions and 
Pyrogallic Developers and found them each to be adapted to 
special cases. Formule for the different Developers, which 
are very numerous, can be found in the text books on 
photography The Pyrogallic one which I have found to 
work well, is made as follows: 
PYROGALLIC DEVELOPER. 
Distilled Water, 15 fluid ounces. 
Pyrogallic Acid, 15 grains. 
Crystallizable Acetic Acid, 1 ounce. 
This does not keep as well as the Iron Developer and 
must be preserved in the dark. 
I fix in a saturated solution of Sodium Hyposulphite and 
wash very thoroughly in a copious stream of water. 
