_Originator of the Collodion Process._--All those who take any interest in photography must agree with your correspondent G. C. that M. Le Gray is a talented man, and has done much for photography. G. C. has given a very good translation of M. Le Gray's _last published work_, p. 89., which work I have: but I must take leave to observe, that it is no contradiction whatever to my statement. The translations to which M. Le Gray alludes, of 1850, appeared in Willat's publication, from which I gave him the credit of having first suggested the use of collodion in photography. The subject is there dismissed in three or four lines. M. Le Gray gave no directions whatever for its application to glass in his work published in July 1851, wherein he alludes to it only as an "encallage" for paper, classing it with amidou, the resins, &c., which he recommends in a similar manner. I had, four months previous to this, published the process in detail in the _Chemist_. I never asserted that he had not tried experiments with collodion in 1849; but he did not give the public the advantage of following him: and I again repeat that the first time M. Le Gray published the collodion process was in September, 1852,--a year and a half after my publication, and when it had become much used. It is obvious that if M. Le Gray had been in possession of any detailed process with collodion on glass in 1850, he would not have omitted to publish it in his work dated July, 1851. F. SCOTT ARCHER. 105. Great Russell Street, Bloomsbury. 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. H. W. D.