acid oxidizes boron phospho-di-iodide with incandescence.  Dilute nitric acid oxidizes it to phosphoric and boric acids.  It burns spontaneously in chlorine, forming boron chloride, chloride of iodine, and pentachloride of phosphorus.  When slightly warmed in oxygen it inflames, the combustion being rendered very beautiful by the fumes of boric and phosphoric anhydrides and the violet vapors of iodine.  Heated in contact with sulphureted hydrogen, it forms sulphides of boron and phosphorus and hydriodic acid, without liberation of iodine.  Metallic magnesium when slightly warmed reacts with it with incandescence.  When thrown into vapor of mercury, boron phospho-di-iodide instantly takes fire.

The second phospho-iodide of boron obtained by M. Moissan is represented by the formula BPI.  It is formed when sodium or magnesium in a fine state of division is allowed to act upon a solution of the di-iodide just described in carbon bisulphide; or when boron phospho-di-iodide is heated to 160 deg. in a current of hydrogen.  It is obtained in the form of a bright red powder, somewhat hygroscopic.  It volatilizes in vacuo without fusion at a temperature about 210 deg., and the vapor condenses in the cooler portion of the tube in beautiful orange colored crystals.  When heated to low redness it decomposes into free iodine and phosphide of boron, BP.  Nitric acid reacts energetically with it, but without incandescence, and a certain amount of iodine is liberated.  Sulphuric acid decomposes it upon warming, without formation of sulphurous and boric acids and free iodine.  By the continued action of dry hydrogen upon the heated compound the iodine and a portion of the phosphorus are removed, and a new phosphide of boron, of the composition B_{5}P_{3}, is obtained.—­Nature.

* * * * *

BORON SALTS.

A paper upon the sulphides of boron is communicated by M. Paul Sabatier to the September number of the Bulletin de la Societe Chimique.  Nature gives the following:  Hitherto only one compound of boron with sulphur has been known to us, the trisulphide, B_{2}S_{3}, and concerning even that our information has been of the most incomplete description.  Berzelius obtained this substance in an impure form by heating boron in sulphur vapor, but the first practical mode of its preparation in a state of tolerable purity was that employed by Wohler and Deville.  These chemists prepared it by allowing dry sulphureted hydrogen gas to stream over amorphous boron heated to redness.  Subsequently a method of obtaining boron sulphide was proposed by Fremy, according to which a mixture of boron trioxide, soot, and oil is heated in a stream of the vapor of carbon bisulphide.  M. Sabatier finds that the best results are obtained by employing the method of Wohler and Deville.  The reaction between boron and sulphureted hydrogen only commences at red heat, near the temperature of the softening