CAVENDISH. 20 



water would be. The experiments made with this apparatus con- 

 sisted in observing, with many precautions, the movements of a 

 long lever delicately suspended by the centre, so as to hang hori- 

 zontally, and furnished at either extremity with small leaden balls. 

 When two much larger and heavier balls of the same metal were 

 brought near the smaller ones, the latter were attracted towards 

 them with a certain force, the measurement of which supplied one 

 essential datum for the determination of the mean density of the 

 earth. No greater compliment to the accuracy of the ' Cavendish 

 Experiment' (as the researches taken as a whole are generally 

 called) can be afforded, than the slight difference which appeared 

 when the experiment was repeated at a later period by Francis 

 Baily, who, with extraordinary precautions to ensure a correct re- 

 sult, and with all the improvements which forty fertile years had 

 added to mechanical contrivances, determined the density to be 5*6, 

 or a little more than five-and-a-half times that of water. 



The last paper which Cavendish published, on an improvement 

 in the manner of dividing astronomical instruments, appeared in 

 1809, a year before his death. His published papers give, how- 

 ever, but an imperfect notion of the great extent of ground over 

 which he travelled in the course of his investigations, and of the 

 success with which he explored it. He was an excellent mathema- 

 tician, electrician, astronomer, meteorologist, and geologist, and a 

 chemist equally learned and original. He lived retired from the 

 world among his books and instruments; he never meddled with 

 the affairs of active life, but passed his whole time in storing his 

 mind with the knowledge imparted by former inquirers, and in ex- 

 tending its bounds. His dress was of the oldest fashion; his walk 

 was quick and uneasy ; he never appeared in London unless lying 

 back in the corner of his carriage ; and he probably uttered fewer 

 words in the course of his life than any man who ever lived to 

 fourscore years. His private character has been thus described by 

 Dr. George Wilson, from whose comprehensive life of Cavendish 

 the present memoir has been chiefly taken : 



" Morally it was a blank, and can only be described by a series of 

 negations. He did not love, he did not hate, he did not hope, he 

 did not fear, he did not worship as others do. He separated himself 

 from his fellow men, and apparently from God. There was nothing 

 earnest, enthusiastic, heroic or chivalrous in his nature; and as lit- 

 tle was there anything mean, grovelling or ignoble. He was 

 almost passionless. An intellectual head thinking, a pair of won- 

 derfully acute eyes observing, arid a pair of very skilful hands 

 experimenting or recording, are all that I recognize in his memo- 

 rials. His brain seems to have been but a calculating engine ; his 

 eyes inlets of vision, not fountains of tears ; his hands instruments 

 of manipulation, which never trembled with emotion, or were 

 clasped together in adoration, thanksgiving or despair; his heart 



