In the absence of cyanide of potassium, a solution of pure hyposulphite of soda will answer as a fair substitute.
To Redeem, a Solarized Impression.—The Daguerreotype plate, prepared in the ordinary manner, should be exposed in the camera a sufficient time to solarize the impression. Then, before it be exposed to the vapor of mercury, expose it for a very brief period to the vapor of either chlorine, bromine or iodine. Then expose over mercury, as usual. I have produced singularly interesting results by this process.
To Purify Water.—Filter the water well, and then add about three drops of nitric acid to the pint. This can be used as absolutely pure water, but I would recommend the use of distilled water as preferable.
Cleaning Mercury.—Make a small bag of chamois skin, pour in the mercury, and squeeze it through the leather. Repeat this several times, and filter by means of a funnel made of paper, with a very small aperture, through which it will escape and leave the particles of dust, or other substances, in the paper. A paper with a pinhole through it will answer as well, and it is less difficult to make.
Adhesive Paper.—Take gum arabic, four ounces, put it in a wide-mouthed bottle and pour on water about one-third above the gum. Add half ounce of isinglass, or fish glue, and a small piece of loaf sugar. Let all dissolve, and spread over French letter paper, with a brush or piece of sponge. If once spreading is not enough, perform the same operation a second time.
Black Stain for Apparatus.—Dissolve gum shellac in alcohol, or procure shellac varnish at the druggists’, stir in lampblack, and apply with a sponge or bit of rag. This will adhere to metal, as well as wood, and is used for the inside of camera, tubes, etc.
Sealing Wax for Bottles.—Melt together six parts rosin and one beeswax, and add a small quantity of lampblack; or, if red is preferable, add red lead. Common white wax is best, as most chemicals act less upon it.
When bottles containing bromine are to be sealed, it is well to grease the stopper. This, however, only when the bottle is in frequent use, for if it were to be sent by any conveyance it would be likely to fly out.
Rouge.—The method employed by Lord Ross is probably unsurpassed in the production of rouge. He has given his process as follows:
“I prepare the peroxide of iron by precipitation with water of ammonia, from a pure dilute solution of sulphate of iron; the precipitate is washed, pressed in a screw press till nearly dry, and exposed to a heat which in the dark appears a dull, low red. The only points of importance are, that the sulphate of iron should be pure, that the water of ammonia should be decidedly in excess, and that the heat should not exceed that I have described. The color will be a bright crimson inclining to yellow. I have tried both potash and soda, pure, instead of water of ammonia, but after washing with some degree of care, a trace of the alkali still remained, and the peroxide was of an ochrey color, till overheated, and did not polish properly.”