CHEMICAL SCIENCE. 219 



place, could not be determined, inasmuch as a less degree of heat pro- 

 duces in a longer the same effect which a higher temperature pro- 

 duces in a shorter time. The joint action of heat and light was also 

 found more efficacious than either of these agents separately. The au- 

 thor compares the two allotropic modifications of phosphorus \vith those 

 of carbon ; the diamond, v T hen strongly heated, passing into an amor- 

 phous state and becoming black and opaque. Amorphous phosphorus 

 is most readily prepared by exposing common phosphorus to the action of 

 heat or light, and then dissolving out the unchanged substance by means 

 of bisulphide of carbon and filtering, taking care to keep the filter full 

 of liquid till a portion of the filtrate evaporated on a strip of platinum 

 no longer leaves a trace of phosphorus. The substance on the filter is 

 to be boiled with a solution of caustic potash, of density 1.30, and 

 washed first with pure water, then with very dilute nitric acid, and 

 finally again with pure water. The new modification of phosphorus is 

 an amorphous powder, without lustre, and of a color which varies from 

 scarlet red to dark carmine red, but which may become dark brown or 

 brownish black ; when washed, it becomes violet, recovering its origi- 

 nal color when cold. Its density, at 10 C., is 1.964. Amorphous phos- 

 phorus is insoluble in bisulphide of carbon, alcohol, ether, naphtha and 

 perchloride of phosphorus ; boiling oil of turpentine takes up a small 

 quantity of it ; in the air it remains entirely unchanged. It is not 

 luminous in the dark at ordinary temperatures, but becomes slightly so 

 near the temperature at which it ignites. Schrotter considers it prob- 

 able that the black phosphorus of Thenard is the same allotropic mod- 

 ification with that which he has described. Nitric acid readily oxidizes 

 amorphous phosphorus, the increased surface of the latter forming 

 many points of attack. Finally, neither copper nor other metallic 

 substances are precipitated from their solutions by amorphous phos- 

 phorus. The author recommends this substance, in an economical 

 point of view, for the preparation of friction matches and percussion 

 caps, as it possesses over ordinary phosphorus the great advantages that 

 it is neither affected by the moisture of the atmosphere, nor injurious 

 to the health of the workmen. In a second paper the author fully con- 

 firms the results which he had previously attained, and adds, among 

 other interesting facts, the remarkable one, that common phosphorus is 

 capable of decomposing water at a temperature between 250 C. and 

 200 C. It should have been stated above that the amorphous modifi- 

 cation of phosphorus is reconverted into common or crystallizable phos- 

 phorus when heated above its boiling point in an atmosphere of hydro- 

 gen or nitrogen. Pogg. Am., 1850, No. 10. 



FIIOSPlirRET OF TUNGSTEN. 



TTonLER has described a remarkable compound of tungsten with 

 phosphorus, prepared and analyzed in his laboratory by Wright. Im- 

 pure phosphoric acid, containing lime, is to be mixed in coarse powder 

 with tungstic acid, in the proportion of nine of phosphoric to two of tung- 

 stic acid, and the mixture is to be ignited in a charcoal crucible for an 

 hour, at a temperature at which metallic nickel becomes perfectly 



