_Deutosulphuret of copper._ This compound is formed whenever sulphuretted hydrogen gas or a hydrosulphuret is sent into a solution of salt containing the deutoxide, or into the deutoxide just precipitated from any acid. It is a dark brown powder not differing much in appearance from the protosulphuret. It consists of 100 copper and 50 sulphur; the weight of the atom is 84. _Quadrisulphuret of copper._ This compound is formed by mixing quadrisulphuret of lime with a salt of the deutoxide of copper, and diluting the solution. A light brown precipitate falls immediately, which is the quadrisulphuret of copper. It burns with a blue flame, and leaves the protosulphuret. The atom consists of 56 copper and 56 sulphur, or weighs 112; and hence the sulphuret consists of equal parts copper and sulphur. The blue hydrate of copper recently precipitated from a salt of copper and washed, acts upon quadrisulphuret of lime; the results, according to my experience, is quadrisulphuret of copper, and the oxygen unites with the sulphur remaining in the liquor. 22. _Sulphurets of iron._ Sulphur may be united to iron either by the dry or humid way, and that in various proportions. _Protosulphuret of iron._ This compound may be formed by passing a hydrosulphuret into a solution of the green oxide in any acid. It is a black powder. It may also be formed by rubbing a highly heated bar of iron with a roll of sulphur; the two unite in a fluid form and soon congeal into a brownish black mass. It is too a natural production, though not very common; excellent analyses of it, as well as of the common pyrites, were some time ago given by Mr. Hatchett. (See Nicholson’s Journ. VOL. 10.) The protosulphuret is magnetic in a considerable degree; it is soluble in acids, and yields sulphuretted hydrogen. It is proper to notice that the sulphuret of iron is not precipitated from solutions by sulphuretted hydrogen simply or without a base. According to Mr. Hatchett this sulphuret consists of 100 iron, and 57 sulphur, which corresponds with 1 atom iron 25, and 1 of sulphur, 14, nearly.