424 M. de luc’s Barometrical Obfervatiom on 
in order to determine points correfponding to his pits 
and galleries. 
But is this a method that may fafely be depended 
upon ? The fail anfwers, and faves us the trouble of long 
reafonings. A miner, i'olely upon the faith of his Geo- 
meter, and in the abfolute obfcurity of the entrails of 
the earth, undertakes a labour that is to coft him years, 
in daily boring through a rock. Another miner fets out 
to meet him from fome other mine, or from without. At 
the end of a determined meafure, the Gnomes begin to 
hear each other, and at length they meet. I have ob- 
ferved fome of thefe points of rencounter in the galle- 
ries ; it is fometimes difficult to perceive the fmall wind- 
ing which has been neceflary for their meeting end to 
.end. 
It 
dehors, a travers les vallees et les collines, des points correfpondants a fes gale- 
ries et a fes puits. 
Eft-ce done la une methode dans laquelle ou purffe vraiment prendre con- 
fiance? Le fait parle ici, et epargne les raifonnemens. Le mineur, fur la foy 
de fon Geometre, s’avanture a entreprendre, dans l’abfolue nuit des entrailles de 
la terre, un travail qui lui coutera des annees, en per^ant journellement le 
rocher. On vient a fa rencontre, de quelqu’autre mine, ou du dehors. Aulxmt 
de la mefure determinee, nos Gnomes viennerft a s’entendre; et enfrn iris fetrou- 
vent. J’ai vu plulieurs de ces points de rencontre dans les galeries; on a peine 
qtfelquefois a apper^evoir le petit evafement qu’il a fallu faire, pour qu’elles fe 
joignent bout a bout. 
II 
