414 de luc’s Barometrical Obfervations on 
mines, where indeed I met with fome irregularities, but 
not fuch as might have been expedled from barely con- 
fidering the local circumftances. 
Thefe mines are in the Ramelfberg near Goflar. The 
ore that is chiefly extracted from them, as well as from 
thofe of Claufthal, is lead ; but they are worked in ano- 
ther manner. The vein of ore, which is near eighteen toifes 
broad, is extremely impregnated with pyrites: infomuch 
that, when you heat it, the vapour of the fulphur, which 
difengages itfelf, burfts the ftone, which falls down in 
large fragments. The method then is to light great fires 
againft the rock; and, when they are extinguilhed, the 
miners aflift with their inftruments the fall of the ftones, 
that may ft ill remain fufpended. 
Sulphureous vapours, therefore, conftantly difengaged 
from the heated ore, circulate in the caverns of the 
mountain, 
quelques jours apres dans d’autres mines, ou jc trouvai quelque irregularite, mais 
non point fuivant ce que les circonftances locales fembloient devoir en produire. 
Ces mines font dans le Ramelfberg, pres de Goilar. Elies fourniflent prin- 
cipalement du plomb, comme celles de Claufthal ; mais on les exploite d’une 
autre maniere. Le filon, qui a pres de 18 toifes de largeur, eft extremement 
penetre de pyrite; tellement qu’en PechaufFant, les vapeurs du fouffre qui fe 
degage, font crevafterla pierre, qui tombe d’elle-meme en grand lainbeaux. On 
allumedonc de grand feux contre lerocher; et lorfqu’ils fonteteints, lesmineurs 
aident avec des inftrumens, la chute des pierres qui font encore lufpendues. 
II fe detache done prefque conftamment du mineral echauffe, des vapeurs ful- 
fureufes, qui circuient dans les cavernes de la montagne, et dans les puits et 
foupiraviH 
