98 THE HISTORY OF SCIENCE 



pressure to one half its original volume, doubles its 

 resistance ; and that if it is further reduced to one 

 half, for example, from six to three inches, it 

 has four times the resistance of common air. In fact, 

 Boyle had sustained the hypothesis that supposes 

 the pressures and expansions to be in reciprocal pro- 

 portions. 



REFERENCES 



Sir Robert S. Ball, Great Astronomers. 



Robert Boyle, Works (edited by Thomas Birch). 



Sir David Brewster, Martyrs of Science. 



J. L. E. Dreyer, Tycho Brake. 



Sir Oliver Lodge, Pioneers of Science. 



Flora Masson, Robert Boyle ; a Biography. 



