vn] of the Seventeenth Century. 191 



" used the animal lives for some time after the candle has gone 

 " out and its smoke has disappeared, so that we cannot suppose 

 " that it is suffocated by the smoke. 



" The reason why the animal can live some time after the 

 " candle has gone out seems to be as follows. The flame of the 

 " candle needs for its maintenance a continuous and at the 

 " same time a sufficiently full and rapid stream of nitro-aereal 

 " particles. Whence it comes about that if the succession of 

 " nitro-aereal particles be interrupted, even for a moment, or 

 "if these are not supplied in adequate quantity, the flame 

 " presently sinks and goes out. Hence, so soon as the igneo- 

 " aereal particles begin to reach the flame scantily and slowly, 

 " it is soon extinguished. For animals, on the other hand, a 

 " lesser store of the aereal food is sufficient, and one supplied 

 "at intervals, so that the animal can be sustained by the 

 "aereal particles remaining after the candle has gone out. 

 " Here it may be remarked that the movements (expansions) 

 " of the collapsed lungs not a little help towards the sucking 

 " in of aereal particles which may remain in the said flask, 

 " and towards transferring them into the blood of the breathing 

 "animal. Whence it comes about that the animal does not 

 "perish until just before the aereal particles are wholly 

 "exhausted. And hence it is that air in which an animal 

 " is suffocated is diminished in volume more than twice as 

 " much as that in which a candle goes out." 



This latter sentence refers to another aspect of the matter. 

 Physicists were then much exercised and Boyle's experiments 

 in particular had led to much discussion about the ' spring ' 

 (elater) of air — the elastic force (vis elastica) of air, and the 

 pressure of air. 



Mayow observes that when a candle is burnt in a closed 

 vessel over water, the water rises after the primary depression, 

 due to expansion from heating, has passed off; the burning 

 has deprived the air of some of its elastic force. He finds 

 by experiment that exactly the same thing takes place in 

 breathing. When a small animal is made to breathe in a 

 closed vessel standing over water the water rises. When a 

 mouse is put inside a cupping-glass, placed over a piece of wet 



