CHAPTER IV 



PRINCIPLES OF CHEMISTRY 



CHEMISTRY is a science based on the results of experiment, but 

 its real foundation belongs to quite modern times when experi- 

 ment began to take the form of exact measurement. For ages 

 all kinds of chemical operations and manufactures had been 

 practised in a crude way, such as the production of soap, glass, 

 dyes, and pigments, the distillation of alcohol from wine, the 

 production of sulphuric acid from green vitriol, and so forth. 



It was only in the middle of the eighteenth century when 

 Black, and a little later Lavoisier, began to weigh and measure, 

 as accurately as they could, the materials with which they were 

 working or the products obtained in their experiments, that a 

 body of facts was gradually accumulated on which theories 

 could be safely established. 



At different periods in the history of the science various esti- 

 mates have been formed as to the influence of different men or 

 the importance of different discoveries. Many writers have been 

 accustomed to date the rise of chemistry as a branch of science, 

 from the time of Robert Boyle, " The Father of Chemistry " as 

 he has been called, at the end of the seventeenth century. 



Boyle gave the first clear and precise idea of the word element 

 so much used in chemistry. For he got rid not only of the 

 Aristotelian four elements, but of the whole brood of fantastic 

 assumptions which for centuries had clouded the brains of the 

 alchemists. Their tria prima, the salt, sulphur, and mercury of 

 their occult lore, were henceforth to disappear, and the elements 

 of the chemist were simply those substances which were found 

 to be incapable of further analysis. 



An eminent French chemist, Wurtz, about fifty years ago 

 commenced a graphic history of chemical theory with the words 

 " Chemistry is a French science. It was founded by Lavoisier 

 of.immortal memory." 



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