G. C., claiming for Le Gray the merit of the first use of collodion upon
glass, states that a pamphlet upon the subject was published in 1850, and
which was _translated into English at the same time_. Will he oblige me by
stating who published this pamphlet, or where it may be obtained? I have
heard this statement before, and have used every endeavour to obtain a
sight of the publication, but without success. Were the facts as stated by
your correspondent, it would deprive MR. ARCHER undoubtedly of the merit
which he claims; but from all I have been able to learn, Le Gray mentioned
collodion as a mere agent for obtaining a smooth surface to paper, or other
substance, having no idea of making it the sole sensitive substance to be
employed. I have been informed that in Vienna, early in 1850, collodion was
tried upon glass by being first immersed in a bath of iodide of potassium;
and it was afterwards placed in a second bath of nitrate of silver. These
experiments had _very limited_ success, and were never published, and
certainly were unknown to MR. ARCHER.