134 THE PROGRESS OF PHOTOGRAPHY. 
the mass has assumed a jelly form, when it is squeezed 
through a coarse canvas, to thoroughly divide up the to- 
tal bulk into small shreds, which are thoroughly washed, 
either in running water or in many changes of water, 
until all of the free nitrate of silver not converted into 
bromide is washed out. Then the emulsion is carefu!ly 
remelted, a small quantity of freshly-dissolved gelatine 
is added, the whole is filtered, and it is ready to be 
spread upon the paper or glass which is selected to sup- 
port the negative. 
These operations must all be conducted in a room very 
feebly illuminated by ruby light only, and of course the 
finished plate must never be exposed to the actinic rays 
of light until it is exposed in a camera. Itis needless to 
say that the perfection of the dry plate has completely 
revolutionized photography. It has popularized it, and 
not only converted it into a valuable adjunct to art, but 
it has enhanced its commercial value a hundred thousand 
fold. Moreover, it has opened the door for a most fas- 
cinating amusement. A great army of amateurs, already 
numbering many thousands, and yearly increasing, are 
tasting the sweets of out-of-door life with an object in 
view. Men and women, girls and boys, are taken into 
the fields, the woodland, and along the winding streams, 
and impelled to observe and study,the beauties of nature. 
This is doing much to build up and sustain an esthetic 
side to an age which is inclined to be selfish and prosaic. 
For a more extended review of the history of photog- 
raphy, I refer all interested to the very complete work 
on that subject by W. Jerome Harrison. I wish that 
time permitted some allusions to the subjects of lenses 
and printing methods, but these must be reserved for 
another occasion. 
At the conclusion of the address, the subject was dis- 
cussed by the members present. 
8S 
