Читать книгу Henley's Formulas, Recipes and Processes (Applied Chemistry) - Various - Страница 567
Colors For Polished Brass.
Оглавление—The brass objects are put into boiling solutions composed of different salts, and the intensity of the shade obtained is dependent upon the duration of the immersion. With a solution composed of
| Sulphate of copper | 120 grains |
| Hydrochlorate of ammonia | 30 grains |
| Water | 1 quart |
greenish shades are obtained. With the following solution all the shades of brown from orange brown to cinnamon are obtained: {128}
| Chlorate of potash | 150 grains |
| Sulphate of copper | 150 grains |
| Water | 1 quart |
The following solution gives the brass first a rosy tint and then colors it violet and blue:
| Sulphate of copper | 435 grains |
| Hyposulphite of soda | 300 grains |
| Cream of tartar | 150 grains |
| Water | 1 pint |
| Upon adding to the last solution | |
| Ammoniacal sulphate of iron | 300 grains |
| Hyposulphite of soda | 300 grains |
there are obtained, according to the duration of the immersion, yellowish, orange, rosy, then bluish shades. Upon polarizing the ebullition the blue tint gives way to yellow, and finally to a pretty gray. Silver, under the same circumstances, becomes very beautifully colored. After a long ebullition in the following solution we obtain a yellow-brown shade, and then a remarkable fire red:
| Chlorate of potash | 75 grains |
| Carbonate of nickel | 30 grains |
| Salt of nickel | 75 grains |
| Water | 16 ounces |
The following solution gives a beautiful, dark-brown color:
| Chlorate of potash | 75 grains |
| Salt of nickel | 150 grains |
| Water | 10 ounces |
The following gives, in the first place, a red, which passes to blue, then to pale lilac, and finally to white:
| Orpiment | 75 grains |
| Crystallized sal sodæ | 150 grains |
| Water | 10 ounces |
The following gives a yellow brown:
| Salt of nickel | 75 grains |
| Sulphate of copper | 75 grains |
| Chlorate of potash | 75 grains |
| Water | 10 ounces |
On mixing the following solutions, sulphur separates and the brass becomes covered with iridescent crystallizations:
| I.— | Cream of tartar | 75 grains |
|---|---|---|
| Sulphate of copper | 75 grains | |
| Water | 10 ounces | |
| II.— | Hyposulphite of soda | 225 grains |
| Water | 5 ounces |
Upon leaving the brass objects immersed in the following mixture contained in corked vessels they at length acquire a very beautiful blue color:
| Hepar of sulphur | 15 grains |
| Ammonia | 75 grains |
| Water | 4 ounces |
