of Cry s t al Zisa t io n . By JAMES ERNEST MARSH. MANY halogen salts, which individually arel very sparingly soluble in organic solvents, readily dissolve when two are mixed together, thereby forming a double salt. One of the two is an alkali or alkaline earth salt, and the other the salt of a heavy metal. This applies especially to the iodides, less t o the bromides, and still less t o the chlorides. The organic solvents in question belong t o the following types : alcohols, ethers, esters, ketones, and aldehydes.