_Mr. Crookes' Wax-paper Process_ (Vol. vi., p. 613.).--R. E. wishes to know
the exact meaning of the sentence, "With the addition of as _much free
iodine_ as will give it a sherry colour." After adding the iodide of
potassium to the water, a small quantity of iodine (this can be proctored
at any operative chemist's) is to be dissolved in the mixture until it be
of the proper colour.
The paper is decidedly more sensitive if exposed wet, but it should not be
washed; and I think it is advisable to have a double quantity of nitrate of
silver in the exciting bath. I have not yet tried any other salt than
iodide of potassium for the first bath; but I hope before the summer to lay
before your readers a simpler, and I think superior wax-paper process, upon
which I am at present experimenting.