232 Biographical Memoir of Horace Benedict de Saii»sure. 



fibres, and it was for the purpose of ascertaining the best and 

 most effectual means of employing them, that Saussure's experi- 

 ments were made. But to attain this object, it was also neces- 

 sary to examine all the possible combinations of water and air, 

 and the influence which they experience on the application of heat 

 and pressure; to produce, by artificial means, the maximum of 

 humidity and the maximum of dryness ; and to determine the in- 

 fluence which humidity exercises in its turn upon the expansion of 

 the air and the manifestation of heat. From these experiments 

 we therefore see an almost new science springing up, and Me- 

 teorology beginning to possess rational principles. 



Saussure made choice of hair as the hygroscopic substance, 

 possessing most sensibihty and regularity. This result of his 

 comparisons has been disputed ; but what could neither be ca- 

 villed at,^ nor attacked, were his beautiful observations on the 

 expansion of air in proportion as it is charged with humidity ; 

 on the relations of humidity with pressin-e ; on the nature of 

 the vesicular vapours or fogs which are suspended in the air like 

 so many small balloons ; and on many other points, all more or 

 less new to science, at the period when he published this work. 



Time does not permit us to lay before you the numerous me- 

 chanical details by which he at length rendered his hygrometer 

 and other instruments capable of convenient use, while, at the 

 same time, he gave them the necessary precision. It is suffi- 

 eient to observe, that, in all these investigations, we discover a 

 mind no less accurate than fertile in resources, and calculated to 

 be the model of natural philosophers as much as that of natu- 

 ralists. 



Although Saussure had travelled for twenty years among the 

 mountains ; had fourteen times crossed the Alps, by eight diffe- 

 rent routes ; had made sixteen excursions to the centre of 

 that chain ; although he had traversed the Jura range, the 

 Vosges, the mountains of Switzerland, Germany, Italy, Sicily, 

 and the adjacent Isles, and had visited the extinct volcanoes of 

 France ; yet had he never reached the summit of Mont Blanc, 

 which he beheld every day from his window. Ten times he 

 had attacked it, as it were, by all the valleys which terminate 

 on its sides ; he had gone round it, examined it from the sum- 

 mits of the neighbouring mountains, but had always found it 

 inaccessible. On the 18th August 1787, he learned that two 



