CAVENDISH 39 



acids on zinc or iron, and he describes its properties in 

 the first part of his paper " On Factitious Airs." In the 

 same paper he discussed the properties of fixed air (carbon 

 dioxide), and proved that fixed air and the air produced 

 during fermentation were the same. 



Early in his career Cavendish made researches into 

 the properties of heat discoveries in regard to specific 

 and latent heat which anticipated those subsequently 

 made and published by Black but it is said suppressed 

 them that he might not enter into rivalry with the 

 learned Scotch professor. One pauses in wonder to con- 

 template a man who could give away fame in so easy- 

 going a fashion, and, moreover, was willing to do so. 



The life of Cavendish presents a deeply interesting, 

 but difficult, problem for the student of psychology. 



His immense library was available to all his scientific 

 acquaintances on condition that they did not disturb the 

 owner ; and on one occasion he was induced to allow a 

 fellow- worker of small means to reside in his London library 

 in order to catalogue and rearrange it. After leaving 

 London, the poor fellow was not in the best of health, 

 and was indifferently provided for. It was suggested to 

 Cavendish that he was deserving of " a little annuity for 

 life." "Well, well, well, a cheque for ten thousand 

 pounds, would that do ? " asked Cavendish ; and a cheque 

 for that amount was accordingly written. This was the 

 only generous act in his long life of eighty years ; and he 



