42 1 M. de luc’s Barometrical Obfervations on 
100,85 
That of the vale of Oft erode, 173,56 
Confequently, one of thefe barometrical meafures, 
taken in open air, was found to agree very nearly with 
the geometrical meafure ; and the other differs only ij 
toife in excefs. 
The only thing that remained to be enquired into was, 
whether the geometrical meafures could really be relied 
on; but I foon found that I might truft to the impor- 
tance they were of to the miners, as well as to the daily 
experience of the truth of them; although they be 
made in fo very Angular a manner, that one does ftand 
in need of this experience, to be perfuaded of their 
exaftnefs. 
A twifted 
Le point de'la vallee de Bremeke, au deffous d’Alte Seegen, 100,85 
Celui de la vallee d’Ofterode, 1 73 » 5^ 
Ainli, Tune de ces mefures barometriques fakes en plein air, s’eft trouvec 
prefqu’ entierement femblable a la mefure geometrique; l’autre n’en difFere que 
d’une toife et un tier en exces. 
II ne s’agilToit plus que d’examiner, li les mefures geometriques etoient vrai- 
ment dignes de confiance. Mais je vis bientot, que je pouvois me repofer a cet 
egard fur l’importance dont il eft pour les mineurs qu’elles le foyent; et fur 
1 ’experience qui les verifie tous les jours. Cependant elles s’executent d’une 
maniere ft finguliere, qu’il faut reellement cette experience, pour fe perfuader 
qu’elles font exa&es. 
The point of the valley of Bremeke below Alte 
Seegen, 
