90 
Let well-glazed paper (I prefer that called wove post) 
be steeped in water to which hydrochloric acid has been added 
in the proportion of two drops to three ounces. When well wet, 
let it be washed over with a mixture of syrup of ioduret of iron 
half a drachm, water two drachms and a half, tincture of 
iodine one drop. When this has remained on the paper for a 
few minutes, so as to be imbibed, dry it lightly with bibulous 
paper, and being removed to a dark room, let it be washed 
over evenly, by means of a camel-hair pencil, with a solution 
of nitrate of silver, ten grains to the ounce of distilled water. 
The paper is now ready for the camera. The sooner it is 
used the better; as when the ingredients are not rightly mixed, 
it is liable to spoil by keeping. The time I generally allow 
the paper to be exposed in the camera varies from two to 
thirty seconds ; in clear weather, without sunshine, the me- 
dium is about fifteen seconds. With a bright light, the pic- 
ture obtained is of a rich brown colour ; with a faint light, ora 
bright light for a very short time continued, it is black. For 
portraits out of doors, in the shade on a clear day, the time 
for sitting is from ten to fifteen seconds. Ifthe light is strong, 
and the view to be taken extensive, the operator should be 
cautious not to leave the paper exposed for a longer period 
than five or six seconds, as the picture will appear confused 
from all the parts being equally acted on. In all cases, the 
shorter the time in which the picture is taken the better. 
When the paper is removed from the camera no picture 
is visible. However, when left in the dark, without any other 
preparation being used, for a period which varies with the 
length of time it was exposed and the strength of the light, a 
negative picture becomes gradually developed, until it arrives 
at a state of perfection which is not attained, I think, by 
photography produced by any other process.* It would seem 
* The picture, when developed, is not readily injured by exposure to mode- 
rate light; it ought, however, to be fixed, which may be done by washing it 
with a solution of bromide of potassium, fifteen or twenty grains to the ounce, 
or iodide of potassium, five grains to the ounce. It may either be applied with 
