Art of Photogenic Drawing. 203 



tures only that, as yet, I have observed indications of colour. I 

 have not had time to pursue this branch of the inquiry further. 

 It would be a great thing if by any means we could accomplish 

 the delineation of objects in their natural colours. I am not 

 very sanguine respecting the possibility of this ; yet, as I have 

 just now remarked, it appears possible to obtain at least some 

 indication of variety of tint. 



§ 8. Api^lication to the Microscope. 



I now come to a branch of the subject which appears to me 

 very important and likely to prove extensively useful, the ap- 

 pUcation of my method of delineating objects to the solar mi- 

 croscope. 



The objects which the microscope unfolds to our view, cu- 

 rious and wonderful as they are, are often singularly compH- 

 cated. The eye, indeed, may comprehend the whole which 

 is presented to it in the field of view ; but the powers of the 

 pencil fail to express these minutiEe of nature in their innume- 

 rable details. What artist could have skill or patience enough 

 to copy them ? or granting that he could do so, must it not 

 be at the expense of much most valuable time, which might be 

 more usefully employed ? 



Contemplating the beautiful picture which the solar micro- 

 scope produces, the thought struck me, whether it might not 

 be possible to cause that image to impress itself upon the 

 paper, and thus to let Nature substitute her own inimitable 

 pencil, for the imperfect, tedious, and almost hopeless attempt 

 of copying a subject so intricate. 



My first attempt had no success. Although I chose a 

 bright day, and formed a good image of my object upon pre- 

 pared paper, on returning at the expiration of an hour I found 

 that no effect had taken place. I was therefore half inchned 

 to abandon this experiment, when it occurred to me, that there 

 was no reason to suppose that either the nitrate or muriate of 

 silver, as commonly obtained, was the most sensitive substance 

 that exists to the action of the chemical rays*; and thouo-h 

 such should eventually prove to be the fact, at any rate it was 

 not to be assumed without proof. I therefore began a course 

 of experiments in order to ascertain the influence of various 

 modes of preparation, and I found these to be signally differ- 

 ent in their results. I considered this matter chiefly in a prac- 

 tical point of view; for as to the theory, 1 confess that I can- 

 not as yet understand the reason why the paper prepared in 

 one way should be so much more sensitive than in another. 



* Sir H. Davy somewhere says tliat the iodide is more sensitive, which I 

 have hardly found to be the case in my experiments. 



