a Theory of the Earth 837 
7. A. The form, dimensions, and nature of the moun- 
tain which contains the vein. 
8. Situation of the vein in regard to the strata of the 
mountain ; under what angle it intersects them. 
9. Its situation in regard to the exterior part of the 
mountain ; whether it be parallel to the external inclina- 
tion of the mountain, or whether that inclination be in a 
contrary direction. 
10. The progress of the vein : whether it be subject 
to change its direction or situation, and according to what 
laws ; if there are any indications that precede these 
changes ; any corners, vacuities, or fissures, which inter- 
rupt the course of the vein 5 and how it is found after 
having been lost : situation and distance of the place 
where it is richest. 
11. Lateral veins or ramifications of the principal 
vein ; veins by which it is accompanied, or which run 
parallel to it. 
IS. To verify Werner's theory in regard to veins, the 
fundamental principles of which are as follows 
A. That the spaces occupied by veins have been origi- 
nally empty crevices or fissures. 
B. That these fissures have been afterwards filled 
from the bottom upwards, at a time when the sea still 
covered the mountains ; and by the precipitation or crys- 
tallisation of the substances which were before dissolved 
in the waters of the sea. 
C. That of two veins crossing each other, the most 
modern is that which intersects the other. 
13. That of two veins, one of which stops and diverts 
the course of the other, the most modern is the latter. 
E. That, in the same vein, the parts nearest to the 
sides of the surrounding substance, the salbande , for in- 
stance, are the most ancient ; those in the middle the most 
modern ; and the intermediate ones of a mean antiquity. 
Von. i. u u 
