OF METALLIFEROUS VEINS IN THE MINES OF CORNWALL. 
409 
Explanations. 
Sections of Cross Veins marked thus 
Section dotted, Granite. 
Short line section, Clay Slate. 
The arrows mark the direction of the positive electricity through the wire, which is represented by 
the black lines, and the number of cross marks on the arrows are increased according to the increase 
of electrical intensity. 
© Marks the stations of the Galvanometer. 
Q The copper plate at the bottom of a level. 
O Ditto at the back of a level. They are shaded in proportion to the richness of the veins, 
which are all of copper ore, except Fig. 11 & 18, and those otherwise marked in Fig. 19 & 21. 
B.S. Bottom of the Shaft. 
f s D. Depth from Surface in fathoms. 
00° Temperature at the Stations of the plates. 
■Scale of Juzt/ioms 
10 5 O 10 VO'S 30 40 30 60 
Wires corresponding with the directions of the ore Veins or Lodes, from Fig. 1. to 18. 
Huel Jewel. 
South Lode. 
North Underlie 23°. 
WEST 
EAST. 
