278 LIFE OF HORACE BENEDICT DE SAUSSURE 



of the valley was very marked. The frequency of these distressing 

 maladies in Val d'Aosta, while they are rare or unknown in most 

 of the valleys of the Italian Alps, has not yet been satisfactorily 

 accounted for. De Saussure devoted a chapter to its discussion. 

 May one of the causes be that the population belong to an old 

 and worn-out stock, in which the tumidum guttur of Juvenal 

 has become hereditary ? 



From Aosta the travellers were taken by their friend M. de St. 

 R^al, 1 whose acquaintance they had made in 1787 in theMaurienne, 

 and who was now the Intendant of the Province, to visit the 

 copper and manganese mines of St. Marcel, situated on the right 

 bank of the Dora Baltea half-way to Chatillon. These mines are 

 reputed to have been worked in Roman times, and traces of the 

 ancient galleries were pointed out. It may be remembered that 

 Strabo asserts that the subjugation of the Salassi was hastened 

 owing to their inconveniencing the inhabitants of the lower valleys 

 by diverting streams for the use of the mines. Even more 

 interesting than the mines was a source of which de Saussure 

 gives a full description : 



* A spring large enough to turn a mill, of which the waters, them- 

 selves blue, covered all their channel, rocks, stones, wood, and earth, 

 with a substance of every shade between green and blue ; what was 

 under the water was deep sky-blue, what was half-wet green, what 

 was dry pale sky-blue. The stream itself, of which the water is per- 

 fectly transparent, runs over this painted bed, breaks into spray, 

 and presents by its reflection the most singular effect ; it resembles 

 the coloured flames produced by throwing verdigris on burning logs.' 

 [Voyages, 2295.] 



An analysis showed that the sediment left by the water contained 

 19 per cent, of copper. 



De Saussure lingered so late over this fascinating stream that 

 the party was benighted on the rough mountain path ; and de 

 Saussure 's mule, which he had luckily got off, put one of its legs 

 through a rotten bridge, and was only saved by breaking up the 

 planks and letting it fall into the torrent. It was midnight when 

 the party got back to St. Marcel, and found the Cur6, who was to 

 lodge them, in bed and asleep. 



This was to be de Saussure's filial adventure in the mountains. 



1 See p. 360. 



