84 PHOTOGRAPHIC PROCESSES. 



an hour take some more of the waste water, and add 

 a few drops of silver solution, and if there is no pre- 

 cipitate of bromide of silver, the emulsion is washed 

 enough. If there is still a precipitate of bromide of 

 silver, continue to wash until, upon trial, there is no 

 precipitate formed. Stirring the emulsion several 

 times will hasten the washing. Never take off the 

 cover to the washing box, except in red light after 

 you add the brine. 



The emulsion is now ready to be preserved for 

 future use, or to be used at once. 



To use at once, tie a piece of coarse canvas over a 

 large bowl, pour the emulsion on to canvas and let 

 it drain free of excess of water ; put back into pitcher 

 and place into hot water in apparatus described 

 hereafter. Melt at a temperature of 140 to 150. 

 Add two ounces alcohol and two ounces pure albu- 

 men. (To prepare the albumen, beat the white of 

 eggs to a stiff froth and set aside to go back to liquid). 

 Add two drops of a saturated solution of chrome alum 

 in water to each ounce of emulsion; this is to keep the 

 gelatine from frilling. There should be 35oz. of 

 emulsion when finished ; if not, make up with water. 

 Make smaller quantities in proportion. 



To FLOW THE PLATES. 



Filter the emulsion through a piece of moist 

 flannel in the glass funnel, placed in the tin funnel 

 as described hereafter ; filter into a small pitcher 

 that will hold about six ounces. You can have 



