128 ARRANGEMENT OP APPARATUS. 



dry process, ten times the precautions are neces- 

 sary here, as the slightest touch will ruin the plate. 



We shut the slide and convey the plate in as 

 horizontal a position as possible to the camera, care 

 being taken to avoid its knocking against anything 

 or being shaken during the journey. After insertion 

 it is exposed in the manner previously described, 

 three to six minutes being sufficiently long, and when 

 removed from the camera immediately carried to the 

 dark room. 



Any development suitable for the wet plate pro- 

 cess, is at once proceeded with. The resulting nega- 

 tive, after fixing and subsequent washing, being 

 dried and varnished. 



During the description of this method exception 

 might be taken to needless repetition. We have 

 only one excuse to offer. Having seen numerous 

 failures and the destruction of many plates caused 

 by the neglect of some trifling detail only remedied 

 by perseverance, we prefer repetition on our own 

 part, to failure on that of our readers. 



The following arrangement should be selected by 

 those compelled to adopt one plan alone. Its advan- 

 tages are, the ease and quickness with which the 

 different manipulations are performed; the small 

 number of adjustments necessary; and the absence 

 of all danger of disturbing the centring of the 

 different instruments, as the microscope and camera 

 are not placed in direct continuity. In the former 

 arrangement this was very liable to occur, when fix- 

 ing the bellows front to the camera and microscope, 



