STRONTITES, or STROWTIAN, in mineralogy, is of a green colour ; it oc curs sometimes massive, and sometimes crystallized. This earth was not disco vered till about the year 1791 or 1792. Dr. Crawford, indeed, previously to this period, in making some experiments on what he supposed was a carbonate of ba. rytes, and observing a striking difference between this mineral and the carbonate of barytes which he had been accustom ed to employ, conjectured that it might contain a new earth ; and he sent a spe cimen to Mr. Kirwan for the purpose of analyzing it. This conjecture was fully verified by the experiment of Dr. Hope, Mr. Kirwan, and M. Klaproth, who were all engaged in the same analysis nearly about the same time. This earth is found native in combination with carbonic and sulphuric acids. With the former it is found in considerable quantity in the lead mines of Strontian in Argyleshire, from which it has derived its name, strontites, or stron tian, as it is called by others ; here it oc curs with lead glance, heavy spar, &c. The nature and properties of this earth have been still further investigated by Pelletier, Fourcroy, and Vauquelin. This earth may be obtained in a state of puri ty, either by exposing the carbonate of strontites mixed with charcoal powder to a strong heat, by which the carbonic acid is driven off; or by dissolving the native salt in nitric acid, and decompos ing the nitrate of strontites thus formed by heat. Strontites, obtained by either of these processes, is in small porous frag ments of a greenish white colour. It his an acrid, hot, alkaline taste, and converts vegetable blues to green. The specific
gravity is from 3.4 to 3.6. Light has no perceptible action upon this earth. When It is exposed to heat it may be kept a long time even in a red heat, without un dergoing any change, or even the appear ance offusion. By the action of the blow pipe it is not melted, but is surrounded with a very brilliant white flame. When a little water is thrown on atrontites,it ex hibits the same appearance as barytes. It is slaked, gives out heat, and then falls to powder. If a greater quantity of water be added, it is dissolved. According to Klaprotb, it requires 200 parts of water, at the ordinary temperature of the atmo sphere, for its solution. Boilingwater dis solves it in greater quantity, and when the solution cools, it affords transparent crys tals. These crystals are in the form of rhomboidal plates, or in that of flattened silky needles, or compressed prisms. They effloresce in the air, and have an acrid hot taste. The solution of this earth in water is acrid and alkaline, and converts vegetable blues to green. R is soon covered with a pellicle, by absorb ing carbonic acid from the atmosphere. Strontites has the property of communi cating a purple or red carmine colour to flame., Specimens have been analyzed by various chemists, wbo have obtained different results ; according to Klaproth, the constituent parts are, Strontites . . . . 69 5 Carbonic acid . . 30.0 Water 5 IGO cz