76 Paper Process in Photography, [no. 1, new series, 
paper with a fresh piece on the top, on this lay the wet side of 
your paper, and cover it with another piece of fresh blotting paper 
— blot off the excess of fluid by passing the hand lightly and 
equally over it. Then put in between fresh blotting paper and 
place it in a drawing paper envelope, which may be deposited in 
a portfolio or a flat tin case made for the purpose, until required 
to be put in the slide. This should not be done for about half an 
hour, unless it be intend/^d to expose it immediately, as the eva- 
poration from the paper is cori'densed upon the glass, and forms a 
number of small plano-convex lenses which doubtless refract the 
rays that have passed through the glass of the slide and injure the 
picture. 
I have not had occasion to keep this paper longer than 18 hours 
after exciting, it kept well for that time. 
EXPOSUBE IN THE CaMERA. 
With a given paper and light, the time of exposure will depend 
upon the focal length of the lens, and the aperture of the dia- 
phragm in front of it. My pictures were taken with a Ross' 4 inch 
Landscape lens of 20 inches focus, with an aperture of | an inch 
in the diaphragm. And the time of exposure I found necessary 
will be the best guide I can give to others. 
I took a good negative of the Catholic Cathedral in 9 minutes, 
between 3 and 4 p. m,, the paper having been excited about half 
an hour previous to exposure in the Camera. This is a white 
building much darkened by time. There were some deep shadows, 
the detail in which is fairly rendered: the Cassarina trees also 
would have been tolerably well represented, had it not blown very 
hard at the time. During half the time of exposure, the sun was 
obscured by a small, but dense, black cloud. The Museum was 
taken between 7 and 8 a. m. on paper excited on the previous even- 
ing, it was exposed 9 minutes in bright sunshine. This was per- 
haps exposed rather too long to be called a good negative, al- 
though not altogether to be despised. It need not have been made 
quite so intense, but there was a palankeen carriage and horse in 
very deep shadow under a large tree, which I wished to bring out, 
or else the development could have been stayed earlier. These 
