132 



SEVENTEENTH CENTURY. 



FT. III. 



combustion, or burning, and respiration, or breathing, and try 

 and follow them as carefully as he did. 



It seemed to him clear from the experiments of Boyle 

 and Hooke that there must be something in the air which 

 gave rise to flame and breath, and that this could only be a 

 small part of the air, since a candle when put under a bell- 

 glass went out long before all the air was gone. He first of 

 all satisfied himself by experiments that this gas which 

 burnt, and which he called fire-air, was not only in the 

 atmosphere, but existed in nitre, or saltpetre, and also in 

 many acids ; and then he set to work to discover how much 

 of it there was in ordinary air. To do this he took a piece 

 of camphor, with some tinder dipped in melted sulphur, 

 and placed it on a little platform hung inside a bell-jar (see 

 Fig. 19). He then lowered the bell-jar into a basin of water, 

 having first put a siphon or bent tube under the bell-jar to 

 let enough air out for the water to rise. Then he took the 

 tube out, leaving the water at the same height inside and 

 outside the jar, while the rest of the jar above the water was 



Fig. 19. Fig. 20. 



Mayow's experiments on combustion and respiratirai (Yeats)i 



full of air. He now held up a burning-glass, and brought 

 the sun's rays to a focus upon the camphor and tinder till it 

 grew hot and burst into a flame. As it burnt he noticed that 



