HISTORY OF THE ATOMIC THEORY. 239 



his closet merely. By this custom, therefore, Dalton's credit 

 would be the whole theory, minus what Higgins and Richter 

 had done ; how much this was who will venture to declare, 

 the two parts being the conceptions of different brains, so that 

 Thomson, with his great quickness, could make nothing out 

 of one, and Berzelius, with his patience, nothing out of the 

 other ; nevertheless, Dalton must not have their credit, and it 

 was not the habit of his independent spirit to seek from others. 

 Dr. Henry has made it clear that he had not seen Higgins's book. 

 He no doubt saw Proust's results. They are in the library of 

 the Manchester Society, and they are probably the most likely 

 to have assisted him, as the analyses and reasoning are re- 

 markably clear, but devoid, as before said, of theory; still 

 the clearest and best were later than Dalton. This, there- 

 fore, seems to be the result, that although actually producing 

 all the theory within himself, from the world his deserts are 

 that he first saw the great importance of the idea of using 

 atoms to illustrate proportion and definite constitution. He 

 followed up the idea, and found in it a fundamental natural 

 law, as it appears hitherto. He saw the use and importance 

 of multiple proportion, or the adding of atom by atom in 

 twos or in threes, and he proceeded to investigate nature 

 under this impression. He proved that bodies followed laws, 

 such as fitted his hypothesis, which was thenceforth taken 

 into the province of scientific theory. To perform the above 

 it was needful to grasp the idea more firmly than it had 

 been done, to work laboriously, and to decide convincingly. 

 This Dalton did. He then extended this from simple to 

 complex combinations, and gave the first idea as well as proof 

 of compound proportion, laid down the laws orderly into a 

 system, and accompanied the whole by abundant and laborious 

 proofs. He gave the first idea of atomic weights. Under 

 this head came Richter and Fischer's numbers. Richter 

 grappling with those numbers never could obtain a rational 

 theory from the phenomena. Dalton's plan explains these 



