^'T.X, 



» 



IS 



""Si 



^ich i, 



Gently i 



^^ ^t tk 



w 



isfe 



^rttith 





►2cked i 



H 



^ Edinbu 



111 bar. 



ire fre 





q^entlj 



^een the ho 



ut 



> (Jeteaed by 



•articularlyfa. 

 :id to produce 

 1 clofe velTels, 



leir, Vol. II 

 edted in gum 



7 



3 



etable or ani- 



ii 



, of Homberg, 

 all the parts 

 ine, and bone- 

 in the fabrics- 

 ufteiiceisd'f- 



he above 



ofpborus 

 h ch are 



con' 

 to be 



ba 



3 



Ul 



) 



ol a 



llitle, 3" 



n 



the 



air- 



A 



Votw 



the 



•d li^^ 



buii^'" 





\s 



-ell '' 



3111 



■,[1)31 



Oll^^ 



) 



Sect.X. 5 



3- 



MANURES 



209 



ones, contain acid of phofphor 



r 



A that in this experiment th 



d of the alum takes the fixed alkaline fait from the vegetable 



a(hes 

 bon 



d the calcareous 

 with the oxy 



th 



f fuch there be, and that th 



f the phofphoric acid ; and the veg 



; exadlly 



table phofphorus is left mingled with the earth of alum 



the fame manner as the animal phofphorus is obtained from the aOies 



of bones, or the fait of urine, by calcining them in clofe vefTels with 



charcoal. 



\ 



of 



3. An important queftion now occurs r if thisfimple m 

 phofphorus be not generally made in the velTels of vegetables, whencer 



do they acquii 

 quantity from th 



it? 



fiderablc 



They may probably obtain 



ements of decaying vegetable and animal bo 



dies ; as it appears in rotten wood, and in putrefying fifli, and 



its 



fuch large quantit 



bone-afties, and in the fait of 



B 



I fuppofe there is another great fource of phofphorus, I mean in cal 

 careous earth, which alfo has been of animal origin in the early age 

 of the world. 



common. 



If an oyfter-fliell be calcined for about half an hour in a 

 fire, and is then kept from the air in a cold place ; when it is after- 

 wards expofed for a while to the funfliine, and brought into a dark 

 room it willappearluminous like the calcined Bolognian ftone ; which 



the phofph 



acid thus deprived of its oxygen by th 



carbon of the fire-coals, and intermingled with the pure calcareous, 

 earth or lime of the fiiell ; and which again combining with the oxy- 

 gen of the air, both light and heat are emitted in the reprodudion o£ 

 phofphoric acid. See Wilfon on Phofphori, Dodfiey, London, 1795 



The Bolognian fione is a felenite or gypfum, w 



vitriolic 



hich 



fifts of 



d and calcareous earth, and I fuppofe of acid of phofpho- 

 fince on mixing the powder of this ftone with gum arabic, and 

 calcining it fome time, a kind of phofphorus is produced fimilar to the 

 above, owing I fuppofe to the carbon of the fire coals, or of the gum 



abic, carrying ofFthe oxygen from the phofphoric acid ; which p 



E 



fly 



If 



r 



