186 Prof. Rood on the application © 
Art. XXII.—On the Practical Application of Photography to the 
Microscope; by Prof. O. N. Roop, of Troy, N. Y. 
WHILE the value of the photographic delineation of micro- 
scopic 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 inhe- 
rent, mostly disappear when proper precautions are taken. I 
propose to mention briefly certain points in my experience, and 
to indicate the methods pursued. . 
Arrangement of the Apparatus.—The microscope is brought 
into a horizontal position, and connected with a camera box by 
a blackened paste board tube; much vexation will be avoided 
by constructing at the outset the arrangement seen in the wo 
A 
cut, fig. 1. Blocks are fitted around the foot of the micro- 
scope, that it may be firmly held in position, and the camera 
box slides between parallel strips of board, so that its distance 
from the microscope can be varied. The length of A A’ 8 
seven feet. The frame holding the ground glass slides in at G; 
behind it at L, is a door on hinges carrying an achromatic lens 
of two inches focal length, for the purpose of magnifying the 
image on the ground glass while focusing; the glass plate should 
be finely ground. A tube lined with black velvet is to be nse 
* In Vienna microscopic photographs have been produced under the direction of 
Aver. Pont and Wesexsky have also wo i 
Kais, Akad, 1857, xxiii, vol. 1, 17); at an earlier date Mayer f Frank se 
obtained fine photographs of t d. Be similar results eho 
French Academy ( Comptes Rendus, 1857, xliv). Nacuet also ob’ “a “ae 
Mi ce, 1858, ii, p. 147), Detves, (3 No we 
Wauenam (same Journal, Ag No. 10, p. 
June, p. 461), have published accounts of their more or less successful res 
Harrine on the Microscope, Braunschweig, 1859. To the above must be add ad 
great work now being issued in numbers in Munich entitled Adlas der ig 
theirischen Gewebelehre, herausgegeben von Tu. v. Husstine und J. KontMaNn, 
der Natur photographist von Jos, ALBERT. 
