486 Mr. de luc on Barometrical Meafures 
It was on the 5th of July that I went clown into it. I 
had heen informed that I might not perhaps be able to 
arrive at the loweft galleries becaufe of the foul air which 
had been there all the preceding days. Some miners 
therefore went before to examine how far we might go 
down without danger. Mr. uslar, who had been fo 
kind as to accompany me to the mines of R.amelfberg, 
was alfo pleafed to be of this party, as well as Mr. fre- 
Peric, one of the officers of the mines, a gentleman well 
ikilled in fubterraneous geometry. And whilft we were 
under ground Mr. mayer, one of the clerks of the office 
of the mines, obferved his barometer above ground every 
quarter of an hour. 
It had been fine weather for fome days, and that day 
it was particularly fo; and Mr. mayer perceived no va- 
riation 
Ce fut Ie 5 0 Juillet que j’y defcendis. On me prevint que je ne pourrois peut- 
etre pas arriver jufqu’aux galeries les plus bafles a caufe des mouffettes, dont il y 
avoit eu tous les jours precedens. Quelques mineurs prirent done les devants 
pour examiner jufqu’a ou nous pourrions defeendre fans danger. Monf. de uslar* 
qui avoit eu la bonte de me conduire aux mines du Ramelfberg, voulut bien en- 
core etre de cette partie, demesne que Mr. Frederic, 1’un des oiHciers mineurs* 
tres au fait de la geometrie fouterraine. Et tandis que nous fumes dans l’inte- 
yieur de la terre, Mr. mayer, Fun des officiers du bureau des mines, obferva 
fon barometre chaque quart d’heure a Fexterieur. 
II faifoit fort beau depuis quelques jours, et ce jour la en particulier; ct Mr. 
mayer n’apper§ut aucune variation, dans fon barometre de 4 h. a 9 h. du foir: 
