_Baths for the Collodion Process._--Having lately been assured, by a
gentleman of scientific attainments, that the sensitiveness of the prepared
collodion plate depends rather upon the strength of the nitrate of silver
bath than on the collodion, I am desirous of asking how far the experience
of your correspondents confirms this statement. My informant assured me,
that if, instead of using a solution of thirty grains of nitrate of silver
to the ounce of water for the bath, which is the proportion recommended by
Messrs. Archer, Horne, Delamotte, Diamond, &c., a sixty grain solution be
substituted, the formation of the image would be the work of the fraction
of a second. This seems to me so important as to deserve being brought
under the notice of photographers--especially at this busy season--without
a moment's delay; and I therefore record the statement at once, as, from
circumstances with which I need not encumber your pages, I shall not have
an opportunity of trying any experiment upon the point for a week or two.
Upon referring to the authorities on the subject of the best solution for
baths, I have been struck with their uniformity. One exception only has
presented itself, which is in a valuable paper by Mr. Thomas in the 6th
Number of the _Journal of the Photographic Society_. That gentleman directs
the bath to be prepared in the following manner: