in the Mines of the Hartz. 491 
geometric meafure which had been given me, and I re- 
queued Baron de reden to caufe it to be examined. The 
perfon whom he charged with that care was his nephew, 
who is very fkilful in every thing concerning the mines. 
He examined with Mr. rausch, the chief geometer, the 
meafure which had been given me ; and they found, that 
in writing the depths of the differents parts of the mine, 
the fum of which ought to give the whole depth, one of 
thefe parts had been twice put down, fo that the true 
depth was only 215^ lachters: it became then two feet 
lefs than that which refulted from my obfervations. 
Thus the barometric meafurement gave four feet 
lefs than the geometrical meafure for the former of the- 
depths, and two feet more for the latter. 
I was 
qui m’avoit ete donnee de la mefure geometrique; et je priai M. le Baron de 
reden de la faire examiner. La perfonne qu’il chargea de ce foin, fut fon 
neveu, qui eft tres eclaire dans tout ce qui concerne les mines. II verifia done 
cette note avec Mr. rausch le geometre en chef; et ils trbuverent, qu’en pre- 
nant en detail les profondeurs des differentes parties de la mine, dont la fomme 
devoit donner la profondeur totale, on avoit pofe deux fois une de ces parties; 
deforte que la vraie profondeur n’etoit que 215! liters. Elle etoit done alors 
Kioindrede 2pieds, quecellequi refultoitde mes obfervations, 
Ainfi la mefure barometrique avoit donne 4 pieds de moins que la mefure 
geometrique pout la premiere des profondeurs, et 2 pieds t de plus pour la der- 
niere. 
