134 Refearchcs refpe&ing 



4. The chemical action of Jubilances is weakened in pro* 

 portion to their faturation. (Art. II. No. 10.) It muft he. 

 concluded, therefore, that the refulting affinity muft be a lei's 

 quantity than the elementary affinities when alone: for the 

 latter have experienced a commencement of faturation ; h\x\ 

 other circumttanccs may increafe the action of the refulting 

 affinity, or may augment the weaknefs it derives from fatura- 

 tion. 



5. If one of the fubftances that combine change from a 

 folid to a liquid ftate, it acquires the advantages poflTefled by 

 folvents; and its affinity, before difgui fed by the folid ftate, 

 becomes active ; fq that the refulting affinity may, on this 

 account, be much more confiderable than the elementary 

 affinities appeared to be. Thus, when fulphur is ditlblved by 

 potafh, the fulphuret which proceeds from it exerts a ftrong 

 action upon oxygen gas, as foon. as it has been 'rendered li- 

 quid bv the addition of water, pr has attracted fufBc'ient hu 7 

 midity from the air : becaufe it has by that means loft its 

 force of cohefion, as it would bv igneous f«.ifion ; and becaufe 

 the potafh jikewife exerts an action upon the oxygen, though 

 much weaker than that of the fulphur, fince it cannot alone 

 overcome the elafticity of the gas. The action of the fulphur 

 is diminjfhed by the fum of that attraction which it exerts 

 upon the potafh, and upon the water which ferves as a folvent 

 to the fulphuret ; but it gains much more by the liquidity 

 which it acquires, than it lofes by this faturation. Strictly 

 fpeaking, all thofe fubilances the folidity of which is oveiv 

 come by a folvent, do act by virtue of a refulting force or 

 affinity. 



6. Circumflances contrary to the preceding produce an 

 oppofite effect ; and when fubftances, by combining, become 

 folid, or more difpofed to cryftallize, this circumltance muft 

 he added to the lofs of force anting from the faturation. Pot- 

 afh, for example, and nitric acid, have both the property of 

 diffolving in alcohol, ana! yet alcohol does not difiolve nitrate 

 of potafh 5 that is, the force of cohefion which belongs to 

 that combination, and which, with water, produces its crvf- 

 tallization, has' modified the elementary affinities into the 

 refulting affinity. What confirms this explanation is, that 

 falts which are not cryftalhzable in water, becaufe they op-7 

 poi'e only a feeble cohefion, have, in general, the property of 

 flifTblvinsr in alcohol ; but in fuch a manner, that they are ca- 

 pable of cryftallizing in that' fluid, becaufe the weaker action 

 of the alcohol cannot overcome, exeept to a certain point, 

 the force of cohefion, of which they are not entirely deftitute. 



The 



