830 Hints for the Formation of 
former level, and has afterwards remained in a state of 
elevation ? 
11. Are there dry fogs, such as that of 1783, which 
may be considered as vapours, that have issued from the 
earth by the action of shocks or concussions ? 
chap. xx. 
Observations to be made on Mines of Metal , Coal, anti 
Salt . 
1 . The historical part : the epoch of the discovery of 
a mine ; of its being first worked ; the expense and net 
produce at different periods. If there ever was, or still 
is, a grant of it, and on what conditions. 
1 . A. In regard to the physical part, care must be ta- 
ken to examine whether the ore be in veins or strata $ 
that is to say, whether it intersects the strata of the 
mountain, or be parallel to them. 
2. In mines which consist of veins, the dimensions, 
thickness, and length of the veins are to be examined 5 
their inclination in regard to the horizon, and their di- 
rection in regard to the cardinal points. The miners call 
this direction the hours. 
3. The metal it contains ; the mineralising substance, 
and the kind of mineral which thence results. 
4 . The matrix, or non-metallic fossil, found mixed 
with the ore. 
5. The nature of the soil at the bottom, or that part 
of the mountain on which the vein rests ; nature of the 
covering, or part of the mountain immediately above it. 
6 . Nature of the covering of the veins, or those parts' 
of the vein next to the substance of the mountain. 
7 . Nature of the druses , or crystallised geodes con* 
tained in the vein. 
