240 MEMOIR OF DR. DALTON, AND 



numbers with the greatest ease, and looks on such as a 

 necessity of the fundamental law, instead of the beginning 

 of the inquiry as it was to them. 



It seems to me, then, that what happened historically, 

 happened also intellectually. Dal ton had included his pre- 

 decessors in his more extensive system. He had gone to the 

 summit of the hill, and when coming down, found proofs that 

 they had been making good progress upwards. Higgins had 

 gone at once to the top, as it appears to me, but took no heed 

 to make the needful observations when he was up, or he 

 found the prospect entirely obscured. We are compelled to 

 put reciprocal proportion in a secondary position, as it seems 

 to me it cannot be called a law, but one of the consequences 

 of a law ; and the evidence brought to support it, otherwise 

 than empirically, presupposes some of the principles on which 

 the general laws depend. 



It was by a careful mechanical juxta-position of parts that 

 Dalton arrived at his idea, it is eminently mechanical, and it 

 is remarkable that all progressive views on that subject have 

 been so. He introduced proportional weight into the theory, 

 and found it to agree with facts. His is, therefore, the 

 quantitative atomic theory. In this complete form no one 

 seeks to take from him the honour. The total is so entirely 

 his, that the disputed parts can be held only as a fealty.* 



Although Dalton rigidly held to the idea of atoms, he by 

 no means supposed that we had attained the indivisible atom 



* Dr. Schweigger, in his pamphlet, objects that Dalton's theory was not 

 conceived in the spirit of the ancient theory, because he allowed some atoms 

 to be small and some large. Strange this. The reason that the ancient theory 

 is insufficient, is simply because it was not conceived in the spirit of Dalton's. 

 2nd. Most of the ancients allowed greater and smaller atoms, and various shapes. 

 3rd. Dalton formed his theory in the belief that atoms were of one size, but 

 afterwards saw reason to change his opinion. Dr. Schweigger, therefore, has 

 forgotten the opinion of Dalton and the ancients, as well as Richter's preface, 

 where he calls the permanent neutrality of neutral salts after neutral decompo- 

 sition, a well known fact. He sneers at the atomic theory, thinking that by 

 putting it down, Dalton will fall ; I don't agree with him there, but there is 

 time enough to wait. 



