206 PHOTOGRAPHY AND MICROSCOPIC OBJECTS. 



But now comes the question, What is the process really worth? 

 How far is it available ? and What circumstances limit its applica- 

 tion, and detract from its usefulness ? 



As I said in the first few sentences of my paper, I do not 

 consider that Photo-micrography can supersede the study of 

 natural objects by the microscope. The eye of the observer is a 

 far more potent instrument of research than any artificial con- 

 trivance can possibly be. But there are other difficulties. 

 Unless the object to be delineated lies very nearly in one plane, 

 the different parts cannot be in focus at the same time, and 

 confusion is produced. Again, different colours have very differ- 

 ent effects on the sensitive plate, and as the photographic image 

 is produced only in light and shade, the charm of colour is 

 wanting. And again, there are objects rendered visible to the 

 eye by the microscope, which are of such extreme tenuity that 

 they will not form an optical image of sufficient force to produce 

 a satisfactory photograph. All these things limit the range of the 

 process, and detract from its value as a really scientific means of 

 research ; but as an assistance in the reproduction of microscopic 

 objects, either for the draughtsman or the engraver, it is of great 

 value, and for popular demonstration there can be no better means 

 employed than the display on the screen of magnified images of 

 objects, previously obtained direct from such objects in the camera. 



Such appears to be the position of Photo-microscopy at the 

 present time. The process has been greatly simplified, and 

 though all that the man of science needs has not yet been at- 

 tained, it may in the future help us to reach all that is required. 



[This paper was illustrated at its close by the practical working 

 of the system described. With the camera, a drawing of which 

 we annex, several photographs of microscopic objects were taken 

 in a most perfect manner, and we were much impressed with the 

 exceeding effectiveness and simplicity of the process. — Ed.] 



