Solutions of muriate of lime and carbonate of potash will answer as well. To Form a Liquid From Two Solids. Rub together in a Wedgewood mortar a small quantity of sulphate of soda and acetate of lead, and as they mix they will become liquid. Carbonate of ammonia and sulphate of copper, previously reduced to powder separately, will also, when mixed, become liquid, and acquire a most splendid blue color. The greater number of salts have a tendency to assume regular forms, or become _crystallized_, when passing from the fluid to the solid state; and the size and regularity of the crystals depend in a great measure on the slow or rapid escape of the fluid in which they were dissolved. Sugar is a capital example of this property; the ordinary loaf-sugar being rapidly boiled down, as it is called: while to make sugar-candy, which is nothing but sugar in a crystallized form, the solution is allowed to evaporate slowly, and as it cools it forms into those beautiful crystals termed sugar-candy. The threads found in the center of some of the crystals are merely placed for the purpose of hastening the formation of the crystals. Experiments. 1. Make a strong solution of alum, or of sulphate of copper, or blue vitriol, and place in them rough and irregular pieces of clinker from stoves, or wire-baskets, and set them by in a cool place, where they will be free from dust, and in a few days crystals of the several salts will deposit themselves on the baskets, etc.; they should then be taken out of the solutions, and dried, when they form very pretty ornaments for a room. 2. Fill a Florence flask up to the neck with a strong solution of sulphate of soda, or Glauber’s salt, boil it, and tie the mouth over with a piece of moistened bladder while boiling, and set it by in a place where it cannot be disturbed. After twenty-four hours it will probably still remain fluid. Pierce the bladder covering with a penknife, and the entrance of the air will cause the whole mass instantly to crystallize, and the flask will become quite warm from the latent caloric, of which we have spoken before, given out by the salt in passing from the fluid to the solid state. It is better to prepare two or three flasks at the same time, to provide against accidents, for the least shake will often cause crystallization to take place before the proper time. Changes of Color Produced by Colorless Liquids.