ABSTRACT
WHILE the value of the photographic delineation of microscopic objects, as a means of accurately recording observations, seems to be generally acknowledged, yet, owing to the real or imaginary difficulties with which the process is beset, but very few working microscopists have adopted it.* After eight months of steady experimental work on the subject, this fact appears to me a matter of astonishment, for the difficulties, which are not inherent, mostly disappear when proper precautions are taken. I propose to mention briefly certain points in my experience, and to indicate the methods pursued.
In. Vienna microscopic photographs have been produced under the direction of Auer. Pohl and Weselsky have also worked at this subject. (‘Sitzungsbericht d. Kais. Akad., 1857, xxiii, vol. 1, page 317) ; at an earlier date Mayer, of Frankfort, obtained fine photographs of this kind. Bertsch presentedsimilarresultstothe French Academy (‘Comptes Rendus,’ 1857,xliv.) Nachet also obtained good results. Hodgson (‘Quart. Journ. of Micros. Science’ 1853, ii, p. 147), Delves (3d No. of the same, p. 57), Shadbolt (ibid., p. 165), Huxley (ibid., p. 178, also No. 4, p. 305), Wenham (same journal, 1855, No. 10, p. 1), and Kingsley ‘Phil. Mag.,’ (1853, June, p. 461), have published accounts of their more or less successful results. Harting ‘On the Microscope,’ Braunschweig, 1859. To the above must be added the great work now being issued in numbers iu Munich, entitled ‘Atlas der allgeminen theirischen Gewebelehre, herausgegeben von Th. v. Hessling und J. Kohmann, nach der Natur photographist von Jos. Albert.’
‘Treatise on Photography,’ by Chas. Waldack, Cincinnati, 1860.
‘Humphrey’s Journal,’ Joseph H. Ladd, New York.
‘Quart. Journal of Mie. Science’ No. xxxi, p. 115,
The orthoscopic eye-piece of Grunow consists of an eye lens partially achromatized in combination with a field lens differing in form from the ordinary Huyghenian.—O. N. R.
After this article was in print, I received from a friend a paper of Amasa M. Eaton, Esq. ‘Proceedings B. S. N. H.,’ vol. viii, p. 105. Mr. Eaton has devoted himself with success to the production of ambrotypes of microscopio objects.—O. N R., Troy, N. Y., July 23rd, 1861.
