determined ; and consequently, half the 

 difference of these positions would shew 

 how much the arm was drawn aside by 

 the attraction of the weights. 



" In order to determine from hence 

 the density of the Earth, it is necessary 

 to ascertain what force is required to draw 

 the arm aside through a given space. 

 This Mr Michell intended to do, by 

 putting the arm'in motion, and observing 

 the time of its vibrations, from which it 

 may easily be computed 1 ." 



" Mr Michell had prepared two wooden 

 stands on which the leaden weights were 

 to be supported, and pushed forwards, 

 till they came almost in contact with 

 the case ; but he seems to have intended 

 to move them by the hand. 



"As the force with which the balls 



1 " Mr Coulomb has, in a variety of cases, used 

 a contrivance of this kind for try ing small attractions; 

 but Mr Michell informed me of his intention of 

 making this experiment, and of the method he in- 

 tended to use, before the publication of any of 

 Mr Coulomb's experiments." [Note by Cavendish .] 



