13 S Kefe •arches ref peeling 



eftablifhing thofe properties by experiment ; for we muft pay 

 attention to all the circumftances of chemical action, to ex- 

 plain the remits of that action, or we mult confine ourfelvea 

 to their eftablifiunent or confirmation. 



XV. Recapitulation. 



I. We have frequently remarked that the a£lion of a fub- 

 flance is diminilhed in proportion as it approaches a Itate of 

 faturation; and this diminution of force was applied to ex- 

 plain ieveral chemical phenomena. It was affirmed that a 

 metal could only take a definite portion of oxygen from the 

 nitric acid, becaufe, when the oxygen in the acid is dimU 

 rhthed, the remaining portion is too ftrongly combined with 

 the azote. The property of carrying off only a portion of 

 oxygen from certain metallic oxides was attributed to hydro- 

 gen ; it was admitted that when a fubftance attracts humi- 

 dity from the air, its diflblving force comes to an equili- 

 brium ; fo that, according to the degrees of deficcation of 

 the air, the fubftance may either carry off or give out water 

 to it. It was (liown that the retiftance experienced in expell- 

 ing the laft portions of a fubftance from a combination, 

 either by the action of an affinity or by that of heat, is much 

 greater than at the commencement of the decompofition, and 

 fometimes fuch, that its entire decompofition cannot be ef- 

 fected. Thus it was alcertained that oxygen could be but 

 partially difengaged from the oxide of manganefe by the 

 action of heat. The combinations which are formed when 

 forces are oppofed, do not therefore depend upon the affinU 

 ties alone, but upon the proportions of the fubftances which 

 act. I have therefore only applied to all the phaenomena of 

 chemiftry, what has been unavoidably admitted in fever al of 

 them from obfervation. I have only deduced the immediate 

 confequences. 



a. Thefe are, that fubftances act in proportion to theiF 

 affinity, and to the quantity of them exifting within the 

 fphere of activity ; that the latter may counterbalance the 

 former affinity; and that the chemical aclion of each power 

 is proportionate to the fatu rations it produces. I have de- 

 fined by the word nmf$ 9 or chemical mafs, the quantities .de- 

 termined by a like degree of faturation, and confequently, 

 relative to the capacity of faturation : when ^wo fubftances 

 are in competition in order to combine with a third, each of 

 them obtains a degree of faturation proportionate to its mal's. 

 The fubject of the combination alfo divides its action in pro- 

 portion to the mafl'esj and by varying the latter the remits 

 will alfo be varied. 



3. I have. 



