Inquiry Into the Laws of Affinity. to^ 



It is therefore necelfary either to confider all the conftitutlon of a body, in order to ex- 

 plain its chemical properties, or to content ourfelves with eftablifhing thofe properties by 

 experiment; for we muft pay attention to all the circumftances of chemical aftion, to 

 explain the refults of that action, or we muft confine ourfelves to their cftabiiftiment or 

 confirmation. 



A R T I C L E XV, 



Recapitulation, 



1. It has often been remarked that the aflion of a fubftance is diminiflied, in proportion 

 as it appro^hes to a ftate of faturation : and this diminution of power was made ufeful in the 

 explanation of feveral chemical phenomena. It was affirmed that a metal could only take 

 a definite portion of oxigen from the nitric acid, becaufc when the portion of oxigen in the 

 acid is diminifhed, the remainder is too ftrongly combined with the azote. The property 

 of carrying off only a portion of oxigen from certain metallic oxides was attributed to 

 hidrogen; it was admitted that when a fubftance attradts humidity from the air, its dif- 

 folving force comes to an equilibrium ; fo that according to the degrees of defication of the 

 air, it may either carry off or give out water to it. It was known that the refiftance found 

 in expelling a fubftance from the laft portions of a combination, either by the aftion of an 

 affinity, or by that of heat, is much greater than at the commencement of the decompofi- 

 tion, and fometimes fuch, that its entire decompofition cannot be effe£led. Thus it was 

 afcertained that oxigen could be but partially difengaged from the oxide of manganefe by 

 the adlion of heat. 



The combinations which are formed when forces are oppofed, does not therefore depend 

 upon the affinities alone, but upon the proportions of the fubftances which aft. I have 

 therefore only applied to all the phenomena of chemiftry, what has been unavoidably ad- 

 mitted in feveral of them from obfervation. I have deduced the immediate confequences. 



2. Thefe confequences are, that fubftances a£i: in proportion to their affinity, and their 

 quantity exifting within the fphere of activity; that the latter may compenfate the force of 

 affinity, and that the chemical adlion of each power is proportionate to the faturations it 

 produces. I have defined by the word chemical mafs, or mafs, the quantities determined by 

 a like degree of faturation, and confequently relative to the capacity of faturation : when 

 two fubftances are in competition in order to combine with a third, each of them obtains a 

 degree of faturation proportionate to its mafs. The fubjed of the combination alfo divides 

 its a£tion in proportion to the maffes, and by varying the latter the refults will alfo be 

 varied. 



3. I have confidered all the forces which, by their concurrence or oppofition to the 

 •mutual affinity of the fubftances brought in aftion according to the preceding principle, 

 may have an influence upon chemical combinations and phenomena. They may be reduced 

 to the following heads : the adtion of folvents, or the affinity which they exert according 



Vol. V.—June 1801. P to 



