178 Miscellanies. 
and hence the necessity of getting quit of the mirror placed in cameras, 
for throwing the representation in such a way as to allow of its being 
traced by the artist. Hence, in taking impressions by the camera, the 
prepared paper must be fixed on the back of the box, directly opposed 
to the lens, and the focus properly adjusted. I have found greatad- 
vantage, in taking impressions by the camera, in using the paper moist, 
and keeping it so all the time it is exposed. For this purpose, after 
moistening it, I place it between a cushion and a pane of glass, tied 
tightly together, to prevent, as much as possible, the escape of mois- 
ture. In this way I have succeeded in a few minutes in getting a faint 
outline of the object exposed to the lens. 
I may here mention that the camera affords a good method of ta- 
“king profiles from busts, not by the reflected light from the bust, but 
by interposing it between the lens and the source oflight. The bust, 
for instance, may be placed, during sunshine, at an open window, and 
the image from it thrown on the prepared paper; using the precal- 
tion, of having the face slightly inclined towards the source of light, 80 
as to give its outline as distinctly as possible. 
Etchings.—A method of taking impressions of etchings on glass by 
the photographic process was described by Havell of London. For 
this purpose the glass is covered with etching varnish, and aftet the 
figure is etched on it, it is smoked, so as to darken the varnish to 
prevent the transmission of light; of course, the smoke does not adhere 
to those parts of the glass exposed by the etching needle, and is there 
fore easily wiped off with a cloth, thus leaving the etching free for the 
light to passthrough. On exposing this with the prepared paper be- 
hind it, a beautifulimpression is taken. In taking impressions in this 
way, the varnished side must be placed next the paper, which must 
be kept close upon the etching by means of a cushion, otherwise the 
impression is not well defined. When the glass side is next the pape 
the impression is very indistinct, owing to the light, when it passes 
through the exposed parts of the glass, being diffused, and by which the 
lines run into each other. 
From the ease with which impressions can be got in this ways 
curred to me that the process might be still farther extended, 50 ag 1 
enable us to take copies of oil paintings, or of drawings on boards, 
through which the light does not penetrate, and for this purpos¢ 
have followed different methods. One of these is to cover the glass 
with a transparent varnish, as with a thin solution of Canada balsam 
in oil of turpentine, and, after Jaying it down on the oil painting, to 
etch it out on the varnish, in the usual way; after this, the glass is 10 
be slightly heated, so as to soften the varnish, which is then tobe 
smoked, by holding itin the flame of an argand gas lamp, taking oar? 
it oc- 
Oe 
