The liquid clarifies by standing; may be regarded as a solution of chloride of lime, and must be protected from the air and light.

It may also be made without putting in the water with the hydrate of lime, by merely passing the chlorine into the hydrate of lime.

This last is by some used in preparations for accelerating the operation of taking Daguerreotypes, but when used for this purpose it is in small quantities.
Chloride of Calcium .-- To one part of water add two parts of muriatic acid, and add pieces of common chalk until effervescence ceases; then filter through cotton cloth and evaporate it by placing it in all earthen or porcelain dish, over a slow fire, to the consistency of a syrup.

When cooling, large prismatic crystals of chloride of calcium are formed.

These must be quickly dried by pressing between folds of blotting paper and kept carefully excluded from the air, as it readily attracts hydrogen.