_Mr. Sisson's Developing Solution._--The REV. MR. SISSON, in a letter I
received from him a few days ago, stated that he had been trying, at the
recommendation of a gentleman who had written to him upon the subject, a
stronger developing solution than that the formula for which he published
some time back in your pages, and that it gave splendid positive pictures
with very short exposure in the camera.
Since I received his letter I have been able to corroborate his testimony
in favour of the stronger solution, and have much pleasure in sending you
the formula for the benefit of your readers. It is this: 1-1/2 drachms of
protosulphate of iron in five ounces of water, 1 drachm of nitrate of lead,
letting it settle for some hours; pour off the clear liquid, and then add
to it 2 drachms of acetic acid.