PHOSPHORUS. 



very heavy. It forms a great bed in the 

 province of Estremadura in Spain. In 

 appearance it resembles curved, lamellar, 

 heavy-spar ; but it is harder and lighter 

 than this kind of heavy-spar 



PHOSPHOROUS acid, is obtained by 

 the slow combustion of phosphorus at the 

 common temperature of the air. If phos- 

 phorus, in small pieces, be exposed to 

 the air in a glass funnel placed in a bot- 

 tle, it attracts the oxygen and moisture 

 from the atmosphere, and runs down in- 

 to the bottle. This is the phosphorous 

 acid. By this process, about three times 

 the weight of the phosphorus is obtain- 

 ed. It is then in the form of a thick li- 

 quid, adhering 1 to the sides of the vessel. 

 It vanes in consistence according 1 to the 

 state of the air. Its specific gravity is 

 not known. It has an acid pungent taste, 

 not different from phosphoric acid. It 

 also reddens vegetable blue colours. The 

 phosphorous acid is not altered by light. 

 When exposed to heat in a retort, part 

 of the water combined with it is first 

 driven off', and when it is concentrated, 

 bubbles of air suddenly rise to the surface, 

 and collect in the form of white smoke, 

 and sometimes inflame, if there be any 

 air in the apparatus. If the experiment 

 be made in an open vessel, each bubble 

 of air, when it comes to the surface, pro- 

 duces a vivid deflagration, and diffuses 

 the odour of phosphorated hydrogen gas. 

 This acid is composed of the same con- 

 stituent parts as the phosphoric, and is 

 considered by some as the phosphoric 

 acid holding in solution a small quantity 

 of .phosphorus. Phosphorous acid forms 

 compounds with alkalies, earths, and me- 

 tallic oxides, which are known under the 

 name of phosphites. 



PHOSPHORUS. This singular sub- 

 stance was accidentally discovered in 

 1677 by an alchymist of Hamburgh, nam- 

 ed Brandt, when he was engaged in 

 searching for the Philosopher's stone. 

 Kunkel, another chemist, who had seen 

 the new product, associated himself with 

 one of his friends, named Krafft, to pur- 

 chase the secret of its preparation ; but 

 the latter deceiving his friend, made the 

 purchase for himself, and refused to com- 

 municate it. Kunkel, who at this time 

 know nothing further of its preparation 

 than that it was obtained by certain pro- 

 cesses from urine, undertook the task and 

 succeeded. It is on this account that the 

 substance long went under the name of 

 Kunkel's phosphorus. Mr. Boyle is also 

 considered as one of the discoverers of 

 phosphorus. He communicated the se- 



cret of the process for preparing it to the 

 Royal Society of London in 1680. I is 

 asserted, indeed, by KratH, that he dis- 

 covered the secret to Mr Boyle, having 

 in the year 1678 carried a small piece of 

 it to London, to shew it to the royal fami- 

 ly ; but there is little probability that a 

 man of such integrity as Mr. Boyte would 

 claim the discovery of the process as his 

 own, and communicate it to the Royal So- 

 ciety, if this had been the case. Mr. 

 Boyle communicated the process to God- 

 frey Hankwitz, an apothecary ot London, 

 who for many years supplied Europe 

 with phosphorus, and hence it went un- 

 der the name of English phosphorus. In 

 the year 1774, the Swedish chemists, 

 Gahn and Scheele, made the important 

 discovery, that phosphorus is contained 

 in the bones of animals, and they improv- 

 ed the processes for procuring it. 



The most convenient process for ob- 

 taining phosphorus seems to be that re- 

 commended by Fourcroy and Vauquelin, 

 which we shall transcribe. Take a quan- 

 tity of burnt bones and reduce them to 

 powder. Put luO parts of this powder 

 into a porcelain or stone-ware bason, and 

 dilute it with tour times its weight of wa- 

 ter. Forty parts of sulphuric acid are 

 then to be added in small portions, tak- 

 ing care to stir the mixture after the ad- 

 dition of every portion. A violent effer- 

 vescence takes place, and a great quanti- 

 ty of a;r is disengaged. Let the mixture 

 remain for twenty-four hours, stiri ing it 

 occasionally, to expose every part of the 

 powder to the action of the ucid. The 

 burnt bones consist of the phosphoric 

 acid and lime ; but the sulphhuric acid 

 has a greater affinity for the lime than the 

 phosphoric acid. The action of the sul- 

 phuric acid uniting with the lime, and the 

 separation of the phosphoric acid, occa- 

 sion the effervescence. The sulphuric 

 acid and the lime combine together, be- 

 ing insoluble, and fall to the bottom. 

 Pour the whole mixture on a cloth filter, 

 so that the liquid part, which is to be re- 

 ceived in a porcelain vessel, may pass 

 through. A white powder, which is the 

 insoluble sulphate of lime, remains on the 

 filter. After this has been repeatedly 

 washed with water, it may be thrown 

 away ; but the water is to be added to 

 that part of the liquid which passed 

 through the filter. Take a solution of 

 sugar of lead in water, and pour it gradu- 

 ally into the liquid in the porcelain ba- 

 son. A white powder falls to the bottom, 

 and the sugar of lead must be added so 

 long as any precipitation takes place 



