Phosphorus and Sulphur, i^c. A\9 



jdissolves In it, producing much heat. The solution evapo- 

 rated affords a thick liquid, which is a solution of pur« 

 phosphoric acid, or a hydrat of phosphoric acid. 



When the liquor is treated wiih water in the same way, 

 it furnishes likewise a thick fluid of the consistence of 

 syrup, which crystallizes slowly by cooling, and forms 

 transparent parallelopipedons. 



This substance has very singular properties : when it is 

 iieated pretty strongly in the air, it takes fire and burns 

 brilliantlv, emittinEj at the same time "h'hules of gas, that 

 inflame at the surface of the liquid. This substance may 

 be called hydrophosphorous acid ; for it consists of pure phos- 

 phorous acid and water. This is proved by the action of 

 ^mmonlacal gas upon it.: when it is heated in contact with 

 ammonia, water is expelled and phosphite of ammonia 

 formed ; and it is likewise shown by the results of its de- 

 composition in close vessels, which are phosphoric acid 

 and a peculiar compound of phosphorus and hydrogen. 



Ten parts in weight of the crystalline acid I found pro- 

 .duced aljout 8 5 parts of solid phosphoric acid, and the 

 elastic product must of course have formed the remainder 

 <>f the weight, allowing for a small quantity of the sub- 

 stance not decomposed. 



The peculiar gas is not spontaneously inflammable ; but 

 explod'^s when nilxed with air, and heated to a temperature 

 rather below 21 '2°. 



Its spccitic gravilv appeared from an experiment in which 

 a small quantity of it only was weighed, to be to that of air 

 nearly as 87 to 100. Water absorl-)ed about one-eighth of 

 its volume of this gas. Its smell was disagreeable, but not 

 nearly so fetid as that of common phosphuretted hydrogen. 



When it was detonated with oxygen, it was found that 

 three of it iti volume absorbed more than five in volume of 

 oxygen, and a little phosphorus was precipitated. 



When potassium was heated in contact with it, its volurne 

 increased rapidlv till it became double, and then po further 

 effect was produced. 'I'lie pota^^siuni Vi'as partly converted 

 inlo a !iul)Stance having all the characters «f phosphuret of 

 potassium ; and the residual gas absorbed the same quantity 

 of oxvgin by detonation as pure hydrogen. When sulphur 

 was sublimed in the gas over mercury, the volume was 

 J kewibc dou!)Icd; a compound of phosphorus and sulphur 

 was foinud, and the elastic fluid produced had ail the cha- 

 racters of sulphuretted hydrogen. 



It appears from iK^'se experiments, that the peculiar gas 



^oiisii^ts of 4'.^ of h)droacii in weight to 22"5 phosphorus; 



'D d 2 and 



