HISTORY OF THE ATOMIC THEOKY. 27 1 



into the subject of heat; into the relations of air and moisture 

 to each other; and into a variety of other topics intimately 

 connected with the stability and advancement of chemical 

 philosophy. I therefore agree with you that Mr. Dal ton has 

 strong claims upon the national respect and gratitude, and 

 contend for his title to reward, even though he may not 

 have accomplished anything bearing strictly upon the im- 

 provement of those arts and manufactures, which are the 

 chief sources of our national wealth. For let it be remem- 

 bered, that every new truth in science has a natural and 

 necessary tendency to furnish, if not immediately, yet at 

 some future time, valuable rules in art* Nothing is more 

 common than that a general principle, when first developed, 

 may admit of no obvious practical use; but that a few 

 subsequent discoveries, made perhaps at a small expense of 

 genius or labour, supply links which render it available first 

 to individual, and in due course to public wealth and pros- 

 perity. Not to mention other instances, Mr. Watt derived 

 from Dr. Black's discovery of latent heat, a guiding light to 

 the noblest invention that has ever been placed in the hands of 

 man, for giving him control over the physical world, and even 

 for advancing his progress in moral and intellectual cultiva- 

 tion. The discovery of chlorine also in the laboratory of a 

 retired chemist, brought forth no practical results for several 

 years, but when found by a subsequent philosopher to quicken 

 the whitening of unbleached cotton and linen goods, it was 

 immediately applied by practical men to the art of bleaching, 

 and no one can now calculate its immense influence in giving 

 rapid circulation to the capital employed in the cotton and 

 linen manufactures. Among the abstract truths unfolded by 

 Mr. Dalton, it would not be difficult to point out the germs 

 of future improvements in the practical arts generally, germs 

 which now lie dormant in the shape of purely scientific pro- 

 positions. 



'< But were it otherwise it would surely be unworthy of a 



