374 Mr. Henwood on the Rocks and Veins 
we assume that a motion has taken place to such an extent 
and in such direction as may be requisite, we may solve, at 
least within certain moderate limits, the problem of any single 
heave. The difficulty, however, lies in the mutual connexion 
of several heaves, for the motion which will reduce one series 
of displacements to a tolerable continuity may be found to in- 
crease our difficulties respecting other heaves by the same 
cross-vein, It is therefore only by a comparison of several 
intersections by the same cross-vein, at the same and at dif- 
ferent levels, that we can hope to arrive at truth or certainty. 
In making this comparison I shall confine myself to examples 
in which the identity of the veins is beyond dispute; and I 
now proceed to the details which I think will supply ample 
materials for the confirmation or rejection of this theory. 
(a.) At Wheal Bolton the middle lode dips towards the 
south, and the south lode towards the north, yet the cross- 
course heaves both towards the right-hand,—the former 18 
feet, and the latter 12 feet: and beside being so heaved, both 
of them accompany the cross-course for several fathoms. 
(b.) At Stray Park the north lode dips towards the south, 
and the south lode towards the north, yet at certain levels both 
are heaved towards the right-hand by the Boundary cross- 
course, and also towards the left-hand by the Machine cross- 
course ; at other levels, however, these lodes are simply in- 
tersected by the cross-courses, 
At 146 fathoms deep the south lode is 2 feet wide on the 
western side of the Boundary cross-course, but on its eastern 
side the lode is 6 feet in breadth: thus whilst the south wall 
of the lode seems merely intersected, the north one appears 
to be heaved 4 feet. 
(c.) At Cook’s-kitchen Dunkin’s lode dips to the south, 
and the Middle Engine lode towards the north, but both are 
heaved to the right-hand by the Little cross-course, which also 
intersects one elvan-course on the north, and another on the 
south of the lodes, but heaves neither of them. ; 
(d.) At North Roskear the Caunter lode dips southward, 
and both the Engine and south lodes towards the north, but 
the cross-course simply intersects the two last, whilst it heaves 
the first 8 feet towards the left-hand. 
(c.) At Cardrew Downs the south lode dips to the north, 
and the north lode towards the south, and between them is an 
elvan-course dipping south-west, from which seyeral veins 
strike off into the adjacent slate. The lodes, the elvan-course, 
and the veins of elvan are all traversed by the Little flucan ; 
but whilst the elvans are simply intersected, both lodes are 
heaved towards the right-hand,—the former 24 feet, and the 
