32 BIOGKAPHIES OF SCIENTIFIC MEN 



Cavendish's residences were in Gower Street and Dean 

 Street, Soho, but his favourite home was Cavendish 

 House, Clapham. In the last-mentioned residence (which 

 was demolished in 1905) most of the rooms were converted 

 into laboratories, workshops, and observatories. The 

 author visited Cavendish House and grounds on 9th August 

 1905, and took several photographs. The house was 

 situated on the south side of Clapham Common, and 

 within its walls one of the most remarkable feats of 

 science was accomplished. Just under the vane (centre 

 window of the second storey) was a small room in which 

 Cavendish weighed the earth. 



In 1798 he computed its mean density by comparing 

 the force of terrestrial attraction with that of the attrac- 

 tion of something of known magnitude and density. 

 This done, an approximation of the weight of the earth 

 became possible. The mean of twenty-three experiments 

 was that the earth weighed 5 '45 times that of a globe of 

 water of equal size the accepted figure now being 5*50. 

 This and a vast amount of work was performed within 

 the walls of Cavendish House, which stood in nine acres 

 of beautifully timbered land ; and here one of England's 

 greatest chemists " buried his science and his wealth 

 in solitude." 



It was in this house that exact quantitative work 

 on electricity received a great impetus by the researches 

 of Cavendish. In 1771 he published important contribu- 



