Miscellaneous Intelligence. 143 
r. Delves of his process. 
‘The only arrangement necessary for the purpose is the addition to 
the microscope of a dark chamber, similar to that of the camera obscura, 
having at one end an aperture for the insertion of the eye-piece end of 
the compound body, and at the other a groove for carrying the ground- 
glass plate. 
in the microscope. e eye-piece must be removed from the com- 
pound body, and the object (being well illuminated by reflection from 
the concave mirror) must be adjusted an used upon the ground- 
eight inch glasses, was taken with a more sensitive collodion; and the 
time from ten to fifteen seconds.’ : 
In the production of negative pictures (from which the paper speci- 
mens were obtained) a moment’s exposure to the sunbeam is sufficient 
when using the lowest powers, and with the highest I have varied the 
time from five to ten seconds. 
In conclusion, I beg to submit this method which Ihave found so 
simple and successful, in the hope that the communication ma 
