510 THE POPULAR SCIENCE MONTHLY 



(1737-1820), who, in 1775, in a prospectus of lectures, proposed to dis- 

 course of " his notions and experiments concerning the primary ele- 

 ments and properties of matter," and of " experiments, observations 

 and arguments, persuading that each primary element consists of atoms 

 homogeneal : that these atoms are impenetrable, immutable in figure,, 

 inconvertible, and that, in the ordinary course of nature, they are not 

 annihilated, nor newly created." He also conceived of atoms, of simple 

 particles, and even of gases, as uniting sometimes, in approximately, if 

 not completely, fixed proportions. Yet, he never arrived at true causes, 

 because his experiments failed to dove-tail with his advanced theoretical 

 suggestions. Accordingly, the explicit variety of the former destroyed 

 the implicit unity of the latter, and the status quo ante was main- 

 tained. 21 William Higgins, the claimant of 1814, published his book 22 

 in 1789. It contains forecasts of the atomic theory, such as the 

 following : 



I am likewise of opinion that every primary particle of phlogisticated air 

 is united to two of dephlogisticated air, and that these molecules are surrounded 

 with one common atmosphere of fire. 23 



But, after all, less than a dozen pages of the 300 deal with the 

 subject; and, although he assigned causes for definite proportion and 

 saturation in a few cases, he never suspected a simple, universal and 

 necessary law. His real acuteness led him to see that combining par- 

 ticles had the same weight (multiple proportions), but he missed his 

 chance to generalize in a maze of suspicions directed against the phlo- 

 gistic theory, which had already lost its primacy; his indolence also 

 hindered him, like his eccentricity. 



Ill 



Finally, coming to Dalton's characteristics as a thinker, we may 

 find the clue in his forcible independence. In the preface to Part II. 

 of "A New System of Chemical Philosophy" (1810), he declares: 



Having been in my progress so often misled, by taking for granted the 

 results of others, I have determined to write as little as possible but what I can 

 attest by my own experience. On this account, the following work will be found 

 to contain more original facts and experiments, than any other of its size, on 

 the elementary principles of chemistry. 



Here the strong man places himself on record, and the question of 

 priority takes to flight. Accordingly, I state it as my clear impression 

 that the merits and defects of his achievement are alike traceable to the 

 fact that our laureate lay under direct obligation to but one of his 



21 His chief work is, " Experiments and Observations relating to Acetous 

 Acid, Fixable Air, Dense Inflammable Air, Oils and Fuel, etc." (1780). 



22 " A Comparative View of the Phlogistic and Antiphlogistic Theories, with 

 Inductions, etc." 



23 P. 132 (2d ed., 1791). 



