DALTON. 43 



an outline of his speculations on the subject of the composition of 

 bodies, in which he gave to the world for the first time a ' Table of 

 Atomic Weights.' In the following year he communicated his 

 views on the theory of definite proportions to Dr. Thomas Thomson, 

 of Glasgow, who at once published an abstract of them ; and in 

 1808 Dalton himself published the first volume of his new system 

 of Chemical Philosophy, in which he placed the Atomic Theory on 

 a firm and clear basis, and established the law of Multiple Propor- 

 tions. The value of Dalton's researches on this great subject is 

 immense ; by the promulgation of his views Chemistry became for 

 the first time a science, and one great law or theory was seen to 

 govern its actions ; before it was a series of separate facts, but 

 by this fundamental law and its branches, and by this only, it is 

 preserved as a science. 



Dalton's theory incurred much opposition before it was finally 

 accepted by scientific men, and among the unbelievers in it may be 

 mentioned Sir Humphry Davy. The baronet, however, in the year 

 1826, clearly acknowledged and accurately defined Dalton's dis- 

 coveries in his anniversary discourse, when he made known that 

 the first award of the Royal Society's Prize, founded by George IV. 

 in the year before, would be given to Mr. John Dalton, " for the 

 development of the chemical theory of Definite Proportions, usually 

 called the Atomic Theory, and for his various other labours and 

 discoveries in physical and chemical science." 



During his later life Dalton continued to gain his living as profes- 

 sional chemist, lecturer, and teacher of Chemistry and Mathematics, 

 and contributed to the advancement of science many valuable 

 papers chiefly relating to Chemistry ; he was also accustomed in 

 his analytical researches to use the graduated dropping tube, and 

 may be considered as the originator of analysis by volume. Mr. 

 Dalton was present at the first meeting of the British Association 

 held in York in 1831, and continued to feel a lively interest in its 

 prosperity, and to attend the annual meetings as long as his health 

 permitted him. On the occasion of the second meeting at Oxford 

 in 1832, the honorary degree of D.C.L. was conferred upon him, 

 in conjunction with Faraday, Brown the botanist, and Sir David 

 Brewster. In the summer of the following year, at the meeting of 

 the same society in Cambridge, it was announced by Professor 

 Sedgewick, that the King had conferred on Dalton a pension of 

 150L per annum, which was increased in 1836 to 300?. ; and as his 

 brother Jonathan died about the same time and left him heir to the 

 paternal estate, he became comparatively wealthy. He, however, 

 still continued working according to his strength, and so late as 

 1840 published four Essays, entitled, ' On the Phosphates and Ar- 

 seniates;' 'Microcosmic Salt;' 'Acids, Bases, and Water;' and 

 { A New and Easy Method of Analysing Sugar.' In 1837-8 Dalton 

 was attacked by paralysis, which greatly enfeebled him ; he, how- 



