the Laws of Affinity. 13$ 



The limited fallibility of nitrate of potafh in water arifes from 

 the fallibility of the potafh, as well as of the nitric acid, by 

 water, being: greater than by alcohol. 



7. Bodies acl in proportion to the quantity of them which 

 exiits within the fphere of action. (Art. IV.) Hence we de- 

 duce, that an action much ftronger than that of the compo- 

 nent parts may refult from a combination, when the compo- 

 nents, or one of the two, pafs from the elaftic to the liquid 

 ftate; for they then carry into the fphere of activity a more 

 confiderable quantity, the action of which may confiderably 

 exceed the force loft by the faturation. Thus potafh cannot 

 overcome the refinance which proceeds from the elafticity of 

 the oxygen and azotic gafes; but if thefe two be com- 

 bined, in order to form nitric acid in the liquid ftate, they 

 acl: upon the potafh in a quantity much greater than they 

 could have applied when in the elaftic ftate; and the refult 

 of their action, though weakened by a commencement of 

 faturation, is found to be much more confiderable than if the 

 azote and oxygen had continued in the elaftic ftate. 



8. The affinity of a fubftance which enters into combina- 

 tion with a compound fubftance, concurs with the elementary 

 affinities of the latter, to maintain its compofition againft the 

 action of foreign fubftances, in proportion to the degree of 

 faturation which it produces. Thus iron easily carries off 

 oxygen from azote, or rather, it (hares it, or takes a portion; 

 but as foon as the nitric acid is combined with potafh, iron 

 can no longer feparate its oxygen at an ordinary temperature; 

 but at a higher temperature the difference of dilatation fuffi- 

 cientlv deftroys the refulting affinity of the potafh to caufe 

 the iron to combine with the oxygen. Jn the oxygenated 

 muriatic acid, the fur-oxygen, which is feebly retained by 

 the muriatic acid, paffes eafily into other combinations ; but 

 though it is prefent in a much greater proportion in the 

 oxygenated muriate of potafh, it is carried off with much 

 more difficulty by oxvgenable fubftances. Phofphate of lime 

 is not decomposed by charcoal even at a great degree of heat; 

 but if it be in the ftate of acidulous phofphate, the portion of 

 acid, which may be confidered as in excels, is capable of 

 being decompofed by charcoal, becaufe not prevented by a 

 Sufficiently large mats of the bafe ; and it is this part alone 

 which affords phofphorus, when, in order to obtain this fub- 

 ftance, we ufe phofphate of lime reduced to an acidulous 

 phofphate by the fulphuric acid. 



9. The contrary takes place when, inftead of a fatirrating 

 fubftance, which ferves to ftrcngthen the refulting affinity* 



1 4 WO 



