158 



MEMOIR OF Dll. DALTON, AND 



Table of the numerical expression of the affinities of Jive Acids and 

 seven Bases, according to the constant relations indicated by the 

 most familiar observations.^ 



Baryta 



Potash 



Soda 



Lime 



Ammonia 

 Magnesia. 

 Alumina ., 



At the same time he says,t relating to the figures, *' the 

 numbers which 1 have employed have no certain basis, but 

 because they ^gree with a sufficient number of the most 

 familiar observations, they may be used without inconvenience, 

 until we recognise the necessity of changing them, so as to 

 make them agree with other results." 



Fourcroy gave numbers also on similar principles, but 

 Morveau objects to them as being so small that it was not 

 easy to find intermediate ones, whilst he objects to Kirwan's 

 numbers which gave the weight of the base as the amount of 

 the affinity, because this did not agree with results. 



In these schemes of double decomposition there seems to be 

 a tacit agreement, that the acid which saturated one base, 

 would saturate the second. 



Kirwan experimented very much in the direction which 

 Bergman had followed. He is another of those who nearly 

 discovered the atomic theory, who laboured in a legitimate 

 direction, but whose discoveries and theories on the subject 

 are merged in the higher and simpler law. 



A brief extract will give his results. 



*' The discovery of the quantity of real acid in each of the 



mineral acid liquors, and the proportion of real acid taken up by 



a given quantity of each basis at the point of saturation, led 



mc, unexpectedly, to what seems to be the true method of 



♦ Diet, de Chymic, Vol. I., p. 558. f T'age 557. 



