THE BOOK OF THE LANTERN. 237 



had put away somewhere a jar of chloride emulsion, which 

 I had made some months before, and had left neglected for 

 want of opportunity to make plates from it. Why, thought 

 I, should I not make some 16 by 13 plates with this 

 chloride emulsion ? The thing was no sooner conceived 

 than put in practice, and that night the plates were coated 

 and racked, to the number of eighteen. I also was careful 

 at the same time to cover a few quarter-plates, with which 

 I could make trial exposures. 



There is one great advantage in manipulating chloride 

 emulsion and the plates made from it : it is so insensitive 

 about 100 times less so than bromide plates that the 

 brightest of yellow lights can be used without affecting it. 

 I use a brilliant paraffin lamp, surrounded by a wire fence, 

 and this is covered with a screen of yellow oiled paper. 

 The light given is so great that a book can easily be read 

 at the further end of the room, and my coating-room is 

 quite a large one. 



Two days later I was ready for work, and had the 

 lantern adjusted at the right distance from my focussing- 

 screen on the wall to give an image of the required size. 

 Carefully focussing the first picture, I took one of the 

 little trial-plates, and held it against the focussing- screen 

 for one minute. Upon development it showed under- 

 exposure. One or two more trials resulted in my finding 

 that the correct exposure was ninety-five seconds. I now 

 felt some confidence in dealin^ with the larger plates, and 

 I exposed three, one after another. 



Now came the development. 1 mixed, first of all, one 

 pint of developer from my stock solutions, and this I put 



