CAVENDISH 41 



Repelled the pestilence, restrained the storm, 

 And given new beauty to the human form; 

 Wakened the voice of reason, and unfurled 

 The page of truthful knowledge to the world. 

 They who have toiled and studied for mankind, 

 Aroused the slumbering virtues of the mind, 

 Taught us a thousand blessings to create 

 These are the nobly great ! 



Among Cavendish's other investigations may be men- 

 tioned his work on the thermometer and temperatures ; 

 he proved that heat was a mode of motion, thereby 

 refuting the material theory. The origin of the " fur " in 

 a tea-kettle was first noted by Cavendish, and the fact 

 that hard waters could be rendered soft by the addition 

 of lime was demonstrated by him. He also proved, by 

 quantitative experiments, that fixed air (carbon dioxide) 

 was heavier than common air, and performed other work 

 on gases. He invented the eudiometer ; but his two 

 crowning discoveries were the determination of the 

 composition of water, and the weight of the earth. 



Although Cavendish retained the terminology of the 

 phlogistic doctrine, he practically admitted the essential 

 point of the nouvelle chimie of Lavoisier, namely, that 

 calces are compounds of metals and dephlogisticated air 

 (oxygen). He was elected an F.R.S. in 1764, and in 1801 

 one of the eight foreign associates of the French Acad6mie 

 des Sciences. 



Of posthumous honours, the seventh Duke of Devon- 

 shire, himself a distinguished mathematician, erected and 



