I2S SEVENTEENTH CENTURY. rr. in 



CHAPTER XVI. 



SCIENCE OF THE SEVENTEENTH CENTURY (CONTINUED). 



Boyle's Law of the Compressibility of Gases — This same I,aw dis- 

 covered independently by Marriotte — Hooke's theory of Air being 

 the cause of Fire— Boyle's experiments with Animals under the 

 Air-pump — John Mayow, the greatest Chemist of the Seventeenth 

 Century — His experiments upon the Air used in Combustion — 

 Proves that the same portion is used in Respiration — Proves that 

 Air which has lost its Fire-air is Lighter — Mayow's * Fire-air ' was 

 Oxygen, and his Lighter air Nitrogen — He traces out the effect 

 which Fire-air produces in Animals when Breathing. 



Boyle's Law of the Compressibility of Gases, 1661. — The 

 Hon. Robert Boyle, seventh son of the Earl of Cork, and 

 one of the principal founders of the Royal Society, was born 

 in 1626. He had very delicate health, and when quite 

 young travelled much abroad and learned there a great deal 

 about science even before he was eighteen years of age. He 

 was deeply interested in Galileo's discoveries, and was in 

 Florence when that great astronomer died in 1642. 



After his return to England, when he was at Oxford, he 

 read an account of Guericke's air-pump, and was so de- 

 lighted with this new discovery that he set to work at once 

 to make one without ever having seen the original. He 

 succeeded so well, with the help of his friend and assistant 

 Dr. Hooke, that his air-pump became famous, and many 

 writers have by mistake given him the credit of being the 



