To operate the burner, we place the cylindrical tube, K L M N, in the inner vessel, and pour sulphide of carbon into it up to the level _aa_. This done, we fill the external vessel with water up to the level _bb_. Thanks to the siphons, the water enters the inner vessel, presses the sulphide of carbon, which is the heavier, and causes it to rise in the tube up to the level _a'a',_ where it saturates a cotton wick, which is then lighted. The upper end of the tube is surmounted with a chimney, PQ. which quickens the draught. The combustion may be retarded or quickened at will by causing the level _bb_ of the water to rise or lower. The burner is placed in the room to be disinfected, which, after the wick has been lighted, is closed hermetically. When all the sulphide is burned it is replaced by water, and the lamp goes out of itself. The combustion proceeds with great regularity and without any danger. It takes about five and a half pounds for a room of 3,500 cubic feet capacity. The process is sure and quite economical, since sulphide of carbon is sold at about five cents per pound, which amounts to 25 cents for a room of 3,500 cubic feet capacity. The burner costs ten dollars, but may be used for an almost indefinite period. The process of producing sulphurous acid by the combustion of sulphide of carbon is, as may be seen, very practical and advantageous. It does not affect metallic objects, and it furnishes a disinfecting gas continuously, slowly, and regularly. Mr. Ckiandi's burner may also be applied in several industries. It is capable of rendering great services in the bleaching of silk and woolen goods, and it may also be used for bleaching sponges, straw hats, and a number of other objects.--_La Nature_. * * * * * THE DETERMINATION OF GRAPHITE IN MINERALS. By J.B. MACKINTOSH. In many instances the accurate determination of the amount of graphite present in a rock has proved a rather troublesome problem. The first thought which naturally suggests itself is to burn the graphite and weigh the carbonic acid produced; but in the case of the sample which led me to seek for another method, this way could not be employed, for the specimen had been taken from the surface, and was covered and penetrated by vegetable growths which could not be entirely removed mechanically. Add to this the fact of the presence of iron pyrites and the probable occurrence of carbonates in the rock, and it will be at once seen that no reliance could be placed on the results obtained by this suggested method.