THE WORKROOM 23 



is that of a dark room of comfortable size adjoining the 

 workroom, and the latter should be fitted up with curtains, 

 so that it can be darkened when desired. Ready access 

 to every part of the apparatus must be assured, and 



Fig. 10 



SMALL VERTICAL CAMERA FOR INSTANTANEOUS EXPOSURES 



comfort, without which delicate operations are almost 

 impossible, must not be neglected. Draughts and great 

 fluctuations in temperature should be avoided, as liable to 

 upset fine adjustments. 



Prevention of Vibration. Vibrations are very detri- 



