by 
TRANSACTIONS OF THE SECTIONS. 71 
On a New Method of Photogenic Drawing. By Dr. ScHAFHAEUTL. 
After some observations on the comparatively low value of all draw- 
ings taken by means of the camera-obscura, in an artistical point of 
view, and on the principal points on which Mr. Talbot's and M. 
Daguerre’s methods of fixing the drawings of the camera-obscura were 
founded, the author proceeded to describe his peculiar methods of 
producing photogenic drawings in Mr. Talbot's, that is, in a negative 
way; then, secondly, he described two new methods of obtaining 
photographs in a positive way. His first method tended to obtain a 
paper of very great sensibility by a comparatively short process. He 
recommended Penny’s improved patent metallic paper, and spreading 
a concentrated solution of the nitrate of silver (140 grains to 24 
drachms of fused nitrate to six fluid drachms of distilled water), by 
merely drawing the paper over the surface of the solution contained in 
a large dish. In order to convert this nitrate of silver into a chloride, 
the author exposed it to the vapours of boiling muriatic acid. A coating 
of a chloride of silver, shining with a peculiar silky lustre, was by this 
method generated on the surface of the paper, without penetrating 
into its mass; and in order to give to this coating of chloride the 
highest degree of sensibility, it was dried, and then drawn over the 
surface of the solution of the nitrate of silver again. After having 
been dried, the paper was ready for use; and no repetition of this 
treatment was able to improve its sensitiveness. ‘The author’s process 
for fixing definitively the drawing was as follows:—He steeped the 
drawing from five to ten minutes in alcohol, and after removing all 
superfluous moisture by means of blotting-paper, and drying it slightly 
before the fire, the paper thus prepared was finally drawn through 
diluted muriatic acid, mixed with a few drops of an acid nitrate of 
quicksilver, into the minutiz of the preparation of which we cannot 
here enter. The addition of the nitrate of mercury requires great 
caution, and its proper action must be tried first on paper slips, upon 
which have been produced different tints and shadows by exposure to 
light; because, if added in too great a quantity, the lightest shades 
disappear entirely. The paper, after having been drawn through the 
above-mentioned solution, is washed well in water, and then dried in a 
degree approaching to about 158° Fahr., or, in fact, till the white 
places of the paper assume a very slight tinge of yellow. The appear- 
ance of this tint indicates that the drawing is fixed permanently. The 
author’s way for reversing the drawing is, in the principal points, the 
same as that suggested by Mr. Fox Talbot. 
In order to obtain a photogenic drawing in a direct or positive way, 
the author uses his above-mentioned paper, allows it to darken in a bright 
sunlight, and macerates it for at least half an hour in a liquid, which is 
prepared by mixing one part of the already described acid solution of 
nitrate of mercury with from nine to ten parts of alcohol. A bright 
lemon-yellow precipitate, of basic hyponitrate of the protoxide of quick- 
silver, falls, and the clear liquor is preserved for use. The macerated 
paper is removed from the alcoholic solution, and quickly drawn over the 
