1813.] the Hon, Henry Cavendish, f 



much prepossess strangers in his favour. He was somewhat 

 above the middle size, his body rather thick, and his neck 

 rather short. He stuttered a httle in his speech, which gave 

 him an air of awkardness. His countenance was not strongly 

 marked, so as to indicate the profound abilities which he 

 possessed. This was probably owing to the total absence of all 

 the violent passions. His education seems to have been very 

 complete. He was an excellent mathematician, a profound 

 electrician, and a most acute and ingenious chemist. He never 

 ventured to give an opinion upon any subject, unless he had 

 studied it to the bottom. He appeared before the world first as 

 a chemist, and afterwards as an electrician. The whole of his 

 literary labours consist of 17 papers, published in the Philoso- 

 phical Transactions, and occupying each only a few pages ; but 

 full of the most important discoveries, and the most profound 

 investigations. Of these papers there are ten which treat of 

 chemical subjects, two treat of electricity, two of meteorology, 

 and three are connected with astronomy. Let us take a view of 

 these papers, in the order in which we have mentioned them. 



I. Chemical Papers. 



Mr. Cavendish's first paper was published in the year 1 7 when 

 he was 35 years of age. It was entitled. Experiments on Factitious 

 Air, and constituted a most important step in the science of 

 chemistry. Dr. Hales had demonstrated that air is given out by 

 a vast number of bodies in peculiar circumstances. But he 

 never suspected that any of the airs which he obtained differed 

 from common air. Indeed, common air had always been 

 considered as an elementary substance, to which every elastic 

 fluid was referred. Dr. Black had demonstrated that calcareous 

 spar and the mild alkalies differed from quick lime and the, 

 caustic alkalies, in containing a quantity of air, chemically 

 combined with the lime and the alkaline bodies. He called this 

 BAX Jixed air and though he had not examined its properties, 

 there was reason to conclude, from the observations which he 

 made, that fixed air was not of the same nature vvith common air. 

 Mr. Cavendish, in this paper, demonstrates that there are two 

 species of air quite different in their properties from common 

 air. These two are inflammable air and fixed air. He 

 mentions, hkewise, a third species of air; namely, that given 

 out when metals are dissolved in nitrous acid. It differed, as he 

 showed, from the other species, though he did not examine its 

 properties in detail. 



The inflammable air, (now known by the name of hydroge?! 

 gas) was obtained by dissolving iron, zinc, or tin, io diluted 

 sulphuric or muriatic acids. Iron yielded about rg?^- part of its 



