Dissolve camphor in spirit of wine, and deposit the vessel containing the solution in a very close room, where the spirit of wine must be made to evaporate by strong and speedy boiling. If any one then enters the room with a lighted candle, the air will inflame, while the combustion will be so sudden, and of so short a duration, as to occasion no danger.
To melt Iron in a Moment and make it run into Drops.
Bring a bar of iron to a white heat, and then apply to it a roll of sulphur. The iron will immediately melt and run into drops.
This experiment should be performed over a basin of water, in which the drops that fall down will be quenched. These drops will be found reduced into a sort of cast-iron.
Never-yielding Cement.
Calcine oyster-shells, pound them, sift them through a silk sieve, and grind them on porphyry till they are reduced to the finest powder. Then take the whites of several eggs, according to the quantity of the powder; and having mixed them with the powder, form the whole into a kind of paste. With this paste join the pieces of china, or glass, and press them together for seven or eight minutes. This cement will stand both heat and water, and will never give way, even if the article should, by accident, fall to the ground.
To remove Stains and Blemishes from Prints.
Paste a piece of paper to a very smooth clear table, that the boiling water used in the operation may not require a colour which might lessen its success. Spread out the print you wish to clean upon the table, and sprinkle it with boiling water; taking care to moisten it throughout by very carefully applying a very fine sponge. After you have repeated this process five or six times, you will observe the stains or spots extend themselves; but this is only a proof that the dirt begins to be dissolved.
After this preparation, lay the print smoothly and carefully into a copper or wooden vessel, larger than the size of the print. Then cover it with a boiling ley of potash, taking care to keep it hot as long as possible. After the whole is cooled, strain off the liquor, take out the print with care, spread it on a stretched cord, and when half dry, press it between leaves of white paper, to prevent wrinkles.
By this process, spots and stains of any kind will be effectually removed.