in THE DISCOVERY OF OXYGEN 45 



Scheele as " foul air " (Air and Fire, p. 54), whilst Lavoisier 

 usually called it the "atmospheric mofette"; the French 

 chemists in 1787 (Chemical Nomenclature, p. 26) described 

 it as AZOTE, " from the Greek privative a and oj, life" in 

 order to indicate its inability to support life. It was shown 

 by Cavendish to consist mainly of a gas, present in 

 nitre, to which Chaptal gave the name NITROGEN. (See 

 Chapter X.) 



SUMMARY AND SUPPLEMENT. 



Jean Rey, in 1630, " On an enquiry into the cause wherefore 

 tin and lead increase in weight on calcination," concluded that 

 the gain in weight on calcining tin, lead, and antimony must be 

 due to condensation of air. 



Robert Boyle, in 1673, i n an essay entitled " New Experi- 

 ments to make Fire and Flame stable and ponderable," proved 

 that copper, iron, tin and lead gained in weight when burned, 

 but attributed this to the absorption of igneous particles. This 

 materialistic view of the nature of fire was elaborated in the 

 " phlogiston theory " of Becher and Stahl ; they assumed that 

 combustion and calcination involved an escape of phlogiston, 

 whilst in smelting an ore, or calx, the addition of phlogiston 

 from the fuel revivified the metal. 



Robert Hooke, in 1665, in his " Micrographia," and John 

 Mayow, in 1674, in his "Medico-physical Essays," suggested 

 that air must contain an active principle similar to nitre ; 

 Mayow described this as " spiritus nitro-aereus," or " nitro-aerial 

 spirit." Mayow showed that damp gunpowder would continue 

 to burn under water. He made experiments with air trapped 

 over water, and showed that the volume of air was diminished 

 by the burning of a candle or of camphor, as well as by the 

 breathing of a mouse. 



Antoine Laurent Lavoisier, in 1774, "Memoir on the 

 Calcination of Tin in Closed Vessels," showed that a similar 

 decrease of volume took place when lead and tin were heated 

 by a burning-glass in air confined over water or mercury. He 

 repeated the experiments in which Boyle had calcined tin in 

 sealed glass flasks, but proved that no change in weight took 

 place until the flask was opened ; as the flask did not change in 



