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XXX. Suggestions for the Preparation of Phosphorus. 

 By M. Donovan, Esq,, M.R.I.A* 



PHOSPHORUS, a substance abundantly diffused throughout 

 the animal, vegetable, and mineral kingdom, is obtained 

 by processes which, although they have undergone many altera- 

 tions and improvements during nearly two centuries, are still 

 troublesome, expensive and difficult. According to M. Hellot's 

 method, the description of which occupies many pages in the 

 Memoirs of the Academy of Sciences, 1737, in order to obtain 

 one ounce of phosphorus we must submit to the tedious and dis- 

 gusting process of evaporating nearly three hogsheads of putrid 

 urine. Dolfuss, who was more successful, obtained but 54 grains 

 from 100 pints. Henckel first and Marggraff afterwards, by 

 adding plumbum corneum to urine evaporated to thickness after 

 being allowed to putrify for two months, procured two ounces 

 and a half of phosphorus from nine or ten pounds of the inspis- 

 sated matter: by this improvement the product was doubled, 

 provided that the persons from whom the urine was obtained in- 

 dulged in drinking malt-liquors in preference to vinous. But 

 still its price was enormous. Mr. Boyle induced a chemist 

 named Bilgar to extract it from very old night-soil. By some 

 unknown addition Bilgar produced it so abundantly from this 

 source, that he lowered the price of it to six guineas per ounce, 

 yet made a large fortune. It could now be purchased for about 

 half as many shillings. Giobert, by precipitating fresh urine 

 with acetate or nitrate of lead, obtained a powder, from 100 parts 

 of which he distilled from 14 to 18 of phosphorus. 



But when Gahn discovered that the earthy part of bone con- 

 sists of phosphate of lime, a more abundant and available source 

 of phosphorus was made known to chemists. Crell accordingly 

 decomposed bone-ashes by caustic alkali, dissolved the mass in 

 water, precipitated it by nitrate of mercury, and distilled the 

 phosphate of mercury with charcoal in the usual manner. But 

 the phosphorus so obtained contains mercury ; just as it contains 

 zinc when sulphate of zinc is used for the separation of phos- 

 phoric acid from bone-ashes. 



At length the present processes were contrived : bone-ashes 

 were mixed with dilute sulphuric acid ; a solution was thus ob- 

 tained consisting of phosphoric acid holding some lime dissolved. 

 This was either evaporated to dryness and distilled with char- 

 coal, or it was precipitated with a salt of lead, and the precipitate 

 distilled with charcoal ; or it was neutralized with ammonia, 

 filtered, and evaporated to dryness ; the ammonia was expelled 

 by heat, and the glassy residue finally distilled with charcoal. 

 * Communicated by the Author. 



