PROGRESS IN CHEMISTRY IN THE NINETEENTH CENTURY. 



By Prof. William Ramsay. 



The proo-ress of the science of chemistry forms one phase of the 

 progress of human thought. While at lirst mankind was contented to 

 observe certain phenomena, and to utilize them for industrial purposes 

 if they were found suitable, "philosophers," as the thinking portion 

 of our race loved to call themselves, have always attempted to assign 

 some explanation for observed facts and to group them into similars 

 and dissimilars. It was for long imagined, following the doctrines of 

 the Greeks and of their predecessors, that all matter consisted of four 

 elements or principles, names which survive to this da}^ in popular 

 language. These were "tire," "air," "water," and "earth." It was 

 not imtil the seventeenth century that Boyle in his Sceptical 

 Chymist (1661) laid the foundations of the modern science by point- 

 ing out that it was impossible to explain the existence of the fairly 

 numerous chemical substances known in his day, or the changes which 

 they can be made to undergo, by means of the ancient Greek hypoth- 

 eses regarding the constitution of matter. He laid down the detinition 

 of the modern meaning of the word "element;" he declined to accept 

 the current view that the properties of matter could be modified by 

 assimilating the qualities of fire, air, earth, or water, and he defined an 

 element as the constituent of a compound body. The first problem, 

 then, to be solved Avas to determine which of the numerous forms of 

 matter were to be regarded as elementary, and which are compound, 

 or composed of two or more elements in a state of combination, and 

 to produce such compounds by causing the appropriate elements to 

 unite with each other. 



ANCIENT IDEAS ABOUT THE AIR. 



One of the first objects to excite curiosity and interest was the air 

 which surrounds us, and in which we live and move and have our 

 being. It was, however, endowed w^ith a semispiritual and scarcely 

 corporeal nature in the ideas of our ancestors, for it does not afiect 



^Copyright, 1900, by The Sun Printing and Publishing Association. Keprinted, 

 by special permission, from The Sun, New York, December 30, 1900. 



