in the Mines of the Hartz. 495 
open air, have agreed with the geometric meafures, 
which feems to indicate that the ufual llate of the air of 
the mines, is a mean among the different fates of the 
exterior air as found in the whole of my obferva- 
tions; the almoft conftant ftate of the heat in the mines 
may be the principal caufe of it. 
As to the geometric meafures themfelves, I might 
here give fome very intereihng proofs of their exadl- 
nefs by the defcription of the aftonithing works which 
are undertaken in confequence of them ; but I fhould be 
afraid of being too tedious. And, betides, we may de- 
pend on the miners for the exadtnefs of thofe meafures, 
they being more interefted in them than we are. I thall, 
therefore, conclude this paper with fome general re-? 
marks on barometrical meafurement. 
So 
plein air, s’y font accordees avec les mefures geometriques ; ce qui paroit indi- 
quer, que I’etat habituel de Fair des mines, eft moyen entre les divers etats ou il 
s’eft trouve dans la totalite de mes experiences; et l’etat prefque conftant des 
mines quant a la chaleur, pourroit bien en etre la principale caufe. 
Quant aux mefures geometriques elles memes, je pourrois donner ici des 
preuves tres intereflantes de leur exaditude, par le tableau des ouvrages etonnans 
qu’on entreprend d’apres elles; mais je craindrois d’etre trop long. Et d’ail- 
leurs nous pouvons nous en rapporter aux mineurs fur Texa&itude de ces me- 
fures; iis y ont un plus grand interet que nous. Je conclurai done ce memoire 
par quelques remarques generales fur la mefure barometrique. 
T t t a 
Tant 
