SS^' prepAiiAtion or* phosphoric acid. 



equal parts of concentrated nitric acid and distilled water. 

 A tube of safety is then to be introduced into the same 

 aperture, so that its toothed extremity shall reach the bot- 

 tom of the retort. The apparatus is then to be luted, and 

 dried. 



The process is to commence with heating the sandbath 

 till tlie liquor boils, and the phosphorus melts. A quantity 

 of nitric acid is then to be pourc<l into the funnel, sufficient 

 to produce a levei, without flowing into the retort. 8 gr. 

 [123'5 grs,] of the same acid arc then to be added; which,, 

 by their weight, force into the retort an equal quantity of 

 the liquid, part of which still remains in the tube, without 

 touching the phosphorus. 



The phosphorus, retained at the bottom by its specific 

 gravity, attracts the nitric acid, but, as it receives only a 

 small quantity at a time, the combustion is slow, and ef- 

 fected without danger. 



In proportion as the nitrous vapours in the retort di- 

 minish, a fresh portion of acid is to be poured into the 

 funnel ; and this is to be repeated, till the phosphorus is 

 completely oxigenated. 



To effect the perfect combustion of 32 gr. [494 grs.] of 



Quantity of 

 nit lie- 

 required. 



cid phosphorus, I have employed 128 gr. [1977 grs.] of con- 

 centrated acid; or 192 gr. [2963*5 grs.] of what is com- 

 monly called fuming nitrous acid. 

 Results. ^y operating in this manner, we obtain phosphoric acid, 



mixed with nitrous gas, and a quantity of superfluous liquid, 

 from which it is to be freed by evaporation. This process 

 takes more time with a retort, than it would with a matrass ; 

 but the operator is not exposed to inhale the nitrous gas. 

 The liquid residuum should have the consistence of a thin 

 sirup, and leave streaks on the glass, as milk or oil would do. 

 If the process I have just described produce pure phos- 

 phoric acid; if my simple and ready apparatus secure the 

 operator from the nitrous fumes, and the accidents that might 

 be occasioned by the explosion of the vessels; this apparatus 

 and this process will no doubt be adopted, and perhaps not 

 be thought uninteresting to those, who are engaged ia 

 chemistry. 

 1 



INDEX 



