^84 



constantly required for the analyses of minerals. By degrees the 

 son became associated with the scientific labours of his father, who 

 records that when he resolved upon attempting the ascent of Mont 

 Blanc, in August 1787? his son, then nineteen years of age. expressed 

 the strongest desire to accompany him ; but being apprehensive 

 that he was not sufficiently strong, he was unwillingly obliged to 

 leave him at the Priory at Chamouni, where he made with great 

 care meteorological observations, simultaneously with those carried 

 on at the summit of Mont Blanc. In the month of June of the 

 following year, Theodore de Saussure accompanied his father in 

 the laborious and hazardous expedition to the Col du Geant, where 

 they remained for seventeen days, during which time young De Saus- 

 sure rose every morning at four o'clock, to commence the meteorolo- 

 gical observations, which he continued with unremitting diligence 

 until ten o'clock each night; and so thoroughly did he enter into the 

 scientific pursuits of his parent, that he almost importuned the latter 

 to extend the period of his sojourn amidst those splendid scenes ; 

 which was however eff'ectually prevented by the guides, who, alarmed 

 at the idea of a longer stay amidst those icy heights, destroyed all 

 the remaining provisions, necessarily compelling the De Saussures 

 to descend to Corraayeur. 



From this period we find Theodore De Saussure always accom- 

 panying his lather, who was not slow in availing himself of the great 

 advantages derivable from his son's labours. In 1789, they made 

 the very difficult tour of Monte Rosa, it being the first time that 

 the gold mines of Macugnaga were visited by men of science. It 

 was during this excursion that young De Saussure restored by experi- 

 ments that confidence in the accuracy of the barometer for measu- 

 ring heights, which the assertion of Bouguer had tended to weaken. 

 He made seventy experiments at difi'erent heights, and in calculating 

 the results, was always careful to make the necessary corrections 

 for temperature and humidity, which Bouguer appears to have neg- 

 lected. The enthusiasm and physical energy of young De Saussure 

 were almost too great for his father, who was now aged, and weak- 

 ened by various illnesses, and consequently we often find the latter 

 compelled to resist his son's desire to prolong their arduous excur- 

 sions. 



The storms of the Revolution, more powerful than those of the 

 Alps, at length put an eff'ectual stop to these useful scientific excur- 

 sions, which hud been continued for so many years. Theodore de 

 Saussure, in common with many men of his age, was compelled to 

 leave his country. He visited this country with Alexander Marcet, 

 who many years afterwards became his colleague in the Academy at 

 Geneva. After travelling over England and Scotland, he returned 

 to Geneva, and resolved henceforth to devote his life to scientific 

 pursuits. The taste which he had acquired for chemistry under his 

 father's tuition, had been strengthened in England and in France, 

 where that science was eagerly cultivated; and on his return to 

 Geneva, he determined to select the vegetable kingdom for the field 



