"In 1840 I communicated to Sir John Herschel some very curious results obtained by the use of colored media, which he did me the honor of publishing in one of his memoirs on the subject from which I again copy it." "A paper prepared with muriate of barytes and nitrate of silver, allowed to darken whilst wet in the sunshine to a chocolate color, was placed under a frame containing a red, a yellow, a green, and a blue glass. After a week's exposure to diffused light, it became red under the red glass, a dirty yellow under the yellow glass, a dark green under the green, and a light olive under the blue. "The above paper washed with a solution of salt of iodine, is very sensitive to light, and gives a beautiful picture. A picture thus taken was placed beneath the above glasses, and another beneath four flat bottles containing colored fluids. In a few days, under the red glass and fluid, the picture became a dark blue, under the yellow a light blue, under the green it remained unchanged, whilst under the blue it became a rose red, which in about three weeks changed into green. Many other experiments of a similar nature have been tried since that time with like results. "In the summer of 1843, when engaged in some experiments on papers prepared according to the principles of Mr. Talbot's calotype, I had placed in a camera obscura a paper prepared with the bromide of silver and gallic acid. The camera embraced a picture of a clear blue sky, stucco-fronted houses, and a green field. The paper was unavoidably exposed for a longer period than was intended--about fifteen minutes,--a very beautiful picture was impressed, which, when held between the eye and the light, exhibited a curious order of colors. The sky was of a crimson hue, the houses of a slaty blue, and the green fields of a brick red tint. Surely these results appear to encourage the hope, that we may eventually arrive at a process by which external nature may be made to impress its images on prepared surfaces, in all the beauty of their native coloration." PHOTOGRAPHIC DEVIATIONS. Before taking leave of the subject of photogenic drawing, I must mention one or two facts, which may be of essential service to operators.