GEOLOGY. 659 



bers of which in such places we cannot very well explain. 

 It is, however, probable that they were brought thither 

 by currents of water. Sometimes, too, we find mixed with 

 them traces of the handicraft of the most ancient human 

 races, and sometimes human crania. 



But the difficulties presented by the exploration of grot- 

 toes and mines, the desert nature of the country where their 

 mouths open, and the ignorance of the rude inhabitants of 

 the mountains, have always kept us from seeing a great 

 part of the treasures scattered in the ground. On the other 

 hand, those inflammable gases, which by their frightful rav- 

 ages carry desolation into mines ; those poisonous vapors, 

 those spiritus let hales, as Pliny calls them, which instantly 

 destroy life and extinguish a torch, were they not calcu- 

 lated to freeze with horror those who should dare to pene- 

 trate into the abysses of the mountains ? 



Superstitious alarms also long hindered men from gather- 

 ing the mineral riches which the bosom of the earth incloses. 

 As they are principally found in countries which have been 

 the theatre of the most violent convulsions, it was with un- 

 mixed terror that men approached the wild and gloomy 

 spots where they lay stored up ; and sometimes gross cre- 

 dulity spread the belief that they were guarded by dragons, 

 jealous of the supremacy of their dark domains. To these 

 all the accidents which happened to miners were attributed : 

 at the moment when the fire-damp exploded, it was said 

 that they were seen in the shape of horses, with fiery 

 manes, passing through the ruins and the fire. 



Pacific spirits, however, everywhere effaced the work of 

 these evil genii ; this was a rooted belief in all the mining 



