484 BELL SYSTEM TECHNICAL JOURNAL 



became charges of electricity, positive and negative. Today they are 

 the electron and the positron. Out of all the earlier concepts slowly 

 arose the basic idea of chemistry, that the substantial and ponderable 

 part of the world, matter, composed of solids, liquids and gases, is 

 susceptible to controlled transformation. 



The devising of tests by which various kinds of matter could be 

 recognized was one of the early accomplishments of the chemist. 

 Many such tests were used by the ancients. It was left for Robert 

 Boyle (17th century), famous for his Gas Law, to conceive identifica- 

 tion tests as an important branch of chemistry. Boyle was the first 

 to use the expression "chemical analysis." Lavoisier, of French 

 Revolution era, is credited with having brought about a chemical 

 revolution, one result of which was "quantitative analysis" — methods 

 for determining quantitatively the composition of materials. The 

 Swede Berzelius, working early in the 19th century, analyzed with 

 prodigious industry hundreds of compounds, thus laying the foundation 

 for the quantitative data of chemistry. In the middle 1800's the 

 Belgian chemist Stas repeated and extended Berzelius' work, develop- 

 ing methods and techniques of much greater accuracy. 



With the impetus given to it by Stas' work analytical chemistry 

 might have been expected to hold the center of the chemical stage 

 during the 19th century. But in 1828 the German Wohler synthesized 

 the substance urea from laboratory chemicals. Urea belonged to the 

 vast class of compounds produced by vital processes, and chemists 

 accepted the dogma that these organic compounds could not be other- 

 wise produced. Wohler's synthesis disproved that dogma, and the 

 great Age of Synthetic Organic Chemistry began, destined to occupy 

 chemists' minds for about a century. 



Since little attention had been given to analytical chemistry during 

 these years, it became the step-child of the science, useful but not 

 particularly creative. The natural result was that it became a stag- 

 nant, static science. It had no special apparatus of its own, but had 

 to be content with the instrumentalities designed for other purposes. 

 Similarly, no one had made any special search for chemical reactions 

 particularly adapted to analysis. Interest in synthesis had also begun 

 to wane. Then physical chemistry burst forth to open up new vistas 

 for the science. 



This continued, essentially, until 1910. In the University of Graz, 

 Austria-Hungary, the biochemist Pregl labored for years on a research. 

 Finally he reached a crucial stage of the work. Before him were a 

 few small resultant crystals, whose composition it was necessary to 

 know before further progress was possible. His analyst told him 



