C, The Density of the Earth 



The most ingenious and most im- 

 portant piece of apparatus devised by 

 John Michell at his Yorkshire home was 

 his bold and original invention of the 

 Torsion-balance with which he proposed 

 to determine the mean density of the 

 Earth. It was probably his last feat in 

 mechanical contrivance, at least he did 

 not live to put it into use. After his 

 death the apparatus passed into the hands 

 of Henry Cavendish who, making some 

 modifications and improvements in it, 

 carried out MichelFs purpose with 

 brilliant success, in what has since been 

 known as the " Cavendish experiment. 1 * 

 In communicating his account of the 

 experiment to the Royal Society 1 , Caven- 

 dish, who seemed so indifferent to the 

 recognition of his own scientific work, 

 took care to bear his testimony to the 



1 Phil. Trans, vol. 88 (1798), p. 469. The paper 

 was read to the Society on 2ist June 1798. 



