132 Scientific Intelligence. 



dense and collect the substances that sublime, a copper U-tube 

 through which a rapid current of cold water flows, is placed in 

 the furnace immediately over the crucible, and is surrounded 

 with asbestos card-board. Magnesium pyrophosphate exposed 

 for five minutes to the arc produced by a current of 300 amperes 

 and 65 volts gives a sublimate of magnesium oxide and ordinary 

 phosphorus. Asbestos with 300 amperes and 75 volts almost 

 completely volatilizes in a few minutes leaving only a small resi- 

 due of fused silicate and a globule of magnesium silicide. Cop- 

 per with 300 amperes and 70 volts volatilizes rapidly and con- 

 denses in globules. In contact with air its vapor forms cupric 

 oxide. Silver enters into ebullition and distills readily, condens- 

 ing in fused globules, gray amorphous powder and arborescent 

 fragments. Platinum melts almost immediately and very soon 

 begins to volatilize, condensing in brilliant globules and as a 

 powder. Aluminum with 250 amperes and 70 volts also volatil- 

 izes and condenses in small spherules. Tin with 380 amperes 

 and 80 volts volatilizes readily and condenses in small globules 

 and in fibrous masses. Gold with 360 amperes and 70 volts 

 volatilizes in six minutes to a considerable extent, condensing in 

 small spheres. Manganese, with 380 amperes and 80 volts vola- 

 tilizes very readily; only a small residue of carbide being left 

 from 400 grams of the metal, after ten minutes. Iron with 350 

 amperes and 70 volts volatilizes and condenses as a gray powder 

 mixed with brilliant malleable scales. Uranium with 350 am- 

 peres and 75 volts readily volatilizes and condenses in small non- 

 magnetic spheres free from carbon. Silicon volatilizes with 380 

 amperes and 80 volts and condenses in small spheres mixed with 

 a gray powder and a small quantity of silica. Carbon with 370 

 amperes and 80 volts rapidly changes into graphite and then 

 volatilizes, condensing in very light thin translucent maroon- 

 colored plates, similar to or identical with the maroon-colored 

 variety of carbon noticed by Berthelot, and burning in oxygen 

 readily. Calcium oxide with 350 amperes and 70 volts volatilizes 

 alter 8 or 10 minutes and with 400 amperes and 80 volts it vola- 

 tilizes in five minutes. The oxide condenses entirely as an amor- 

 phous powder. With 1000 amperes and 80 volts, 100 grams of 

 the volatilized oxide can be obtained in 5 minutes. Magnesium 

 oxide volatilizes with more difficulty than calcium oxide and its 

 boiling point is near its melting point. With 360 amperes and 

 80 volts it gives off a quantity of vapor ; distillation becoming 

 very rapid with 1000 amperes and ten volts. 



Moissan has also submitted zirconia and silica to the electric 

 arc. When zirconia is heated in an electric arc with a current of 

 360 amperes and 70 volts it rapidly melts and in about ten min- 

 utes is in complete ebullition giving off thick white vapors which 

 condense to a white powder consisting of opaque microscopic 

 granules which scratch glass and possess all the properties of 

 zirconia, having a specific gravity of 5 '10. The residue in the 

 crucible has a crystalline fracture. In the cooler parts of the 



