ARRANGEMENT OF APPARATUS. 117 



plates are inserted opened, and placed with the zinc 

 and velvet partitions, on some dry support. 



The door of the dark room being securely fastened 

 and the curtain drawn across it, the tin cover is 

 placed over the lamp. 



The tin box containing the packages of dry plates 

 is now opened ; the lid should fall back to a hori- 

 zontal position, thus forming a shelf on which the 

 pasteboard box, in which the plates are packed with 

 its cover, can be placed during the removal of the 

 desired number from it. As we are now using a 

 double dry slide, two plates are removed, and held 

 one above the other by their edges between the 

 thumb and finger of the left hand, with the right we 

 replace the cover on the cardboard box, shut the tin 

 box, and if necessary, cover it with a dark cloth kept 

 for the purpose. 



Holding the plates in our left hand, we go to the 

 support on which the dark slide has been placed, 

 and insert one plate with the gelatine surface down- 

 wards or looking towards the unopened side. The 

 gelatinised surface may be distinguished from the 

 other, by its want of lustre, when reflecting the 

 image of the lamp ; care being taken to use only 

 sufficient light to enable us to barely distinguish the 

 difference. One zinc partition is placed with its 

 velvet side next the back of the plate, the other 

 with it in the opposite direction. The second plate 

 is laid with its back on the velvet side of the second 

 zinc partition, its gelatinised surface then looks to- 

 wards us. Whatever plan is now adopted for fas- 



