316 Intelligence and MiscellUneous Articles, 



tity of phosphate appears, in general, to be at its maximum. The 

 chloride of phosphorus must then be poured off to make it serve for 

 a fresh operation ; the pieces of phosphorus which adhere together, 

 at the bottom of the globe, must be detached, and gradually allowed 

 to fall into cold water. By this proceeding, the considerable increase 

 of temperature is avoided, which would otherwise occur, by a too 

 rapid solution of the phosphoric acid, and of the excess of chloride 

 of phosphorus ; this would occasion the decomposition of the phos- 

 phate of oxide, as will presently appear. I'he water soon becomes 

 of a deep yellow colour by dissolving the phosphate of oxide ; and 

 by decanting and filtering to free it from the suspended phosphorus, 

 a perfectly limpid yellow liquid is obtained. By heating this solu- 

 tion, the phosphate of oxide decomposes at about 177° Fahrenheit 

 into phosphoric acid, and a yellow, finely-divided, flocculent matter, 

 which, however, collects pretty rapidly at the bottom of the water. 

 This substance is hydrated phosphoric oxide, which is nearly inso- 

 luble in water. This hydrate may, in a short time, be washed upon 

 a filter with hot water ; but in order to have the product not soiled 

 by the paper, it must not be dried upon the filter, but it must be 

 removed from it, while moist, to a porcelain capsule, and dried, in 

 vacuo, over sulphuric acid. The oxide not only loses the interposed 

 water, but also that which it contained in combination : the hydrate 

 is decomposed, and perfectly pure oxide of phosphorus remains ; it 

 has the form of small grains, which are of a red colour ; but when 

 finely powdered, it is canary yellow. 



It was proved to contain no chlorine, by dissolving in nitric acid, 

 and finding none in the solution, and it contained no hydrogen ; for 

 by burning with oxide of copper, it yielded no water. By converting 

 this oxide into phosphoric acid, and that into phosphate of lead, it 

 was found to consist, very nearly, of 



Oxygen 11-35 or 1 eq. 8 



Phosphorus .... 88-65 or 4 eqs. 64 



100- 72 



This oxide is insoluble in water, alcohol and aether ; its density is 

 greater than that of water. At the moment of withdrawing it from 

 the vacuum, it has neither smell nor taste, and it remains in this 

 state, either in contact with the air or dry oxygen. But when these 

 gases are moist, it slowly acidifies, yielding a slight odour of phos- 

 phuretted hydrogen. It is not luminous in the dark under any cir- 

 cumstances. 



Out of contact with the air it may be kept at a temperature of 

 about 570° without decomposing, but it becomes of a bright red 

 colour ; at a little below the heat of boiling mercury, it decomposes 

 rapidly, phosphorus distils, and perfectly white phosphoric acid re- 

 mains. When heated in the air, it remains unchanged at a high 

 temperature, and it burns only when it disengages phosphorus. 

 Chlorine converts it into chloride of phosphorus and phosphoric acid. 

 Hydrochloric acid, whether gaseous or in solution, has no effect 

 on this oxide ; when heated with concentrated sulphuric acid, sul- 



