The formula then, as improved by MR. SISSON, is--

Water 5 oz.

Protosulphate of iron 1-1/2 drs.

Nitrate of lead 1 dr.

Formic acid 2 drs.

Perhaps you will give your readers the benefit of it in your next Number.

Having tried it myself, I think they will be delighted with the beautiful

white silvery tone, without any metallic reflection, produced in pictures

developed with it.