JOHN D ALTON 



low; but, nevertheless, on trial, objects viewed 

 through the same appeared to preserve their natural 

 color. 



Dal ton devoted his life to the study of natural 

 phenomena. He made more than 200,000 observa- 

 tions on the conditions of the atmosphere ; he deter- 

 mined conditions existing between rain and the dew ; 

 the degree of heat and cold produced by condensa- 

 tion of the air, and many other meteorological investi- 

 gations. / 



In 1801 he suggested the probability that all gases 

 could be reduced to the liquid state under suitable 

 conditions of low temperature and strong pressure. 

 The last few years has proved the truth of his sur- 

 mise ; all the gases have been liquified and all solidi- 

 fied. In 1801 Dalton published his " New System 

 of Chemical Philosophy," in which he showed that 

 the elementary substances consisted of atoms, peculiar 

 to each element, that united with the atoms of the 

 other elements in exact and definite proportions; that 

 these ratios were constant and absolute for each sub- 

 stance ; the elements uniting with each other only in 

 these proportions, or, in some instances, in a simple 

 multiple thereof. To each of the simple elements, or 

 the atoms thereof, he assigned a certain relative weight, 

 for which he assumed the weight of an atom of hy- 

 drogen (that element having the lowest combining 



171 



