DEVELOPMENT OF THE PLATE. 11J 
Take i oz.—fluid—of liq. ammoniae, sp. gr. ‘SBo, and 
add 9 ozs. of distilled water. Label “ Ammonia, io 
per cent.” 
Note .—When a phial of liq. amm. fort, is opened it is 
well to dilute it at once with equal measure of water, 
or till it shows on the hydrometer sp. gr. -920. This, of 
course, is half strength, and double the quantity of it 
must be used as compared with sp. gr. -88o. 
Take also 1 oz.—chemical—of potassium bromide, 
and dissolve it in such a quantity of water as will, when 
solution is complete, make the whole amount to 10 ozs. 
fluid. 
A normal developing solution may consist of 20 mins, 
of pyro-solution, 30 of ammonia dilution, and 10 of 
bromide solution. (The developer thus consists of one 
grain of bromide, two of pyro, and three minims of 
strong ammonia in an ounce of water.) The solutions 
separately will keep for a long time in good order; the 
ammonia should of course be kept in a well-stoppered 
bottle ; the solutions once mixed will not keep good for 
many minutes. The pyro solution may be obtained 
made up from any photographic dealer under the name 
of “ Sulpho-pyrogallol.” 
If it is found inconvenient to measure so small a 
quantity as 10 mins, of the bromide, a five per cent, or 
any other convenient solution may be used as “ Stock.” 
When a plate has been nearly properly exposed and 
this developer is applied, details may be expected to 
begin to appear in about twenty to thirty seconds ; the 
details will creep up gradually, and density will increase 
