Y5d On so^KO Properties of the Phosphoric Add 



Jieve that benzoic acid is to be foinivi in the urine of every- 

 sound horse; but the principal point is the time when it is 

 voided. It is well known that in the urma cnida of man 

 very little urc is found; nay, it often seems to be entirely 

 wanting. On the other hand, it is always found in the 

 urina coda of persons who are iu a sound condition. May 

 not the case be the sanie wi;h a limals ? Is it not therefore 

 more than probable that the concocted urine of sound horses 

 always contains benzoic acid, when no trace of it is to be 

 found in the crude urine of the same animals ? This dif- 

 fcrence is of so much importance that it ought not to be 

 entirely overlooked. 



XXIV. On some Properties of the Phosphoric Add not yet 

 suffidently known. By M. J. F.Guers-e^, Apothecary of 



I. Susceplihility of crystallization. 



X HE property which the phosphoric acid possesses of being 

 transformed into a vitreous mass by exposure to heat, was 

 one of its characteristic signs first known : this was not the 

 case, however, with its susceptibility of crystallization. It 

 is not improbable that the method long employed of ob- 

 taining it from urine and bones, and the continued fusion 

 of it to free it from the sulphurous acid, may have pre- 

 vented chemists from knowing it in (.hat state of concen- 

 tration in which it shoots into crystals. 



De Lassonne and Cornette f, however, speak of a phos- 

 phoric acid which was in the ratio of 19"8 to water, and 

 vv^hich being mixed in the proportion of two parts to one 

 part of water, formed after cooling a gelatinous kind of 

 saass. This phcenomenon, however, wlule the phosphoric 

 acid was so much diluted, seems to have arisen rather from 

 a. mixture of earthy matier than from the property of the 

 ^cid to crystallize. 



Gpttling X is undoubtedly the first chemist who observed 

 this ppoptrty of the phosphoric acid, which he did acci- 

 dentally, on having siiftered phosphorus to stand for three 

 months in a cellar m a glass filled with carbonic acid : at 

 the end of tins period he found the sides of the glass co- 



• From Schcre- 's ^gemeines Jot/rnal der Cbemif, no. 44., 

 f. Mim. del' Acad, Ue Paris, 1780; and Crcll's Chem. Annals, 17S6, 

 Vol. ii. 



J Gottlin^'s Taschenbuch fur das iahr, 1797. 



vered 



