VOL. tXXXII.] PHILOSOPHICAL TRANSACTIONS. 229 



It appears to me, that the above experiments justify the inference that the 

 joint affinities between respirable air and phosphorus, and between phosphoric 

 acid and mineral alkali, are superior to the affinity between the whole, or at least 

 part, of the respirable air of carbonic acid and charcoal, co-operating with the 

 affinity between that acid and the same alkali. And though I have not ascer- 

 tained the facts with equal satisfaction, the experiments already made seem to 

 warrant the conclusion, that the order of the affinities is such, that carbonic 

 acid united to vegetable alkali, lime, barytes, magnesia, and clay, will be decom- 

 posed by phosphorus in a due degree of heat. With respect to carbonic acid 

 combined with volatile alkali, as might be expected, I could not decompose it, 

 though I transmitted boiling hot phosphorus through a very long tube, contain- 

 ing mild volatile alkali. 



Expermenls wi/h phosphorus applied to giiick-lime, and caustic Jixed alkalis. — 

 1 need not explain that these experiments must confirm or invalidate the con- 

 clusion above drawn, that carbonic acid was decomposed by phosphorus applied 

 to milk alkalis, and earths which contain this elastic fluid. As the quick lime 

 which can be procured in London must contain both water and carbonic acid, I 

 exposed a quantity of this earth 48 hours to the fire of a reverberatory furnace, 

 by which it was contracted to half its former bulk, and was diminished in its 

 weight; it was however still soluble in acids, and affiirded no carbonic acid. In 

 the manner above described, I exposed 240 grs. of it, with 6o grs. of phospho- 

 rus, to heat in a coated glass tube. On breaking the tube, when cold, 1 found 

 at the bottom about 30 grs. of blackish and white powder; and above that, to 

 the extent of 4 or 5 inches, was a rose-coloured powder, which by its contact 

 with air soon became of a reddish brown colour; above this was the quick-lime, 

 scarcely altered in its colour, but it had, like the rest of the powder in the tube, 

 an alliaceous smell. On tasting a little of this reddish powder, I was surprized 

 by its exploding on my tongue. I threw a few grains of it into several ounces 

 of cold water, it did not seemingly dissolve, or turn black, but in a kw minutes 

 emitted air-bubbles, which rose to the surface of the water, and then burst and 

 exploded, producing a white circular cloud, which in ascending expanded gra- 

 dually, till it burst in the air. It continued to emit these bubbles from time to 

 time, during an hour, and then left a grey sediment, which was phosphoric se- 

 lenite and lime, and the water tasted strongly of lime. The same powder, in 

 hot water, exploded more rapidly and loudly than in cold, but not so violently 

 as the phosphoric air obtained by boiling phosphorus in a lixivium of caustic fixed 

 alkali. By putting this powder into an inverted jar of water, I collected a quan- 

 tity of the air which it produced; it had the properties of the phosphoric air al- 

 ready mentioned, and, among others, by standing over water a dny or two, it 

 became no longer spontaneously inflammable, but appeared to have deposited 



