368 H#. B. Hunt on our Sense of the Vertical and Horizontal, 
2. There is a large extent of ore-ground known to exist in the 
mine, and which can, although of a low percentage: of ores, be 
worked at a profit. 
3. There is good stoping ground in the solid parts of the mine, 
which can be profitably wrought. 
_A. The widening of the flucan in descending, and the appear- 
ance of the solid ore-ground at the lowest points yet reached by 
the workings, render it a safe and advisable matter to open the 
mine at a considerably greater depth. Since there it is certain 
reason to believe that good leaders of ore will be cut in the solid 
part of the ground, and to hope that the various branches may 
unite into one master lode or form rich bunches of ore at the 
crossings of the east and west branches. 
_ &. The position of the dressing works is such in relation to 
unsettled ground, that their position must be changed, or prepa- 
rations made for doing so immediately. : 
. A new engine shaft must be commenced to cut the lode at 
80 or 100 fathoms, and must be pushed forward as rapidly as 
possible. 
7. The ore stuff now on the surface will go far towards re- 
turning the cost of all necessary improvements requisite to place 
the mine in a state of great productiveness, and with proper care 
the old works can be kept up with undiminished returns during 
the erection of the new machinery. 
August 1855. 
Art. XX XIV.—On our Sense of the Vertical and Horizontal, 
and on our Perception of Distance ;* by Lieut. E. B. Hunt, 
Corps of Engineers, U. S. A. 
Puenomena are often unobserved or difficult of analysis, by 
reason of their connection with our habitual acts of conscious- 
ness. Conclusions derived from a life-long experience of our 
particular conditions of existence, are practically ranked as intui- 
tions. From infancy onwards, each waking moments’ percep- 
tions go to impress these conditions upon us, as almost of absolute 
necessity. Our relations to space and to the earth, in their ex- 
ternal or apparent form, are so incessantly subjects of our con- 
sciousness, that we come to regard them without special consid- 
eration or question. Asa mind which has spent its habitual en- 
ergies in pursuing analytical geometry, conceives codrdinate axes, 
almost as matters of course in every investigation, so do we all, 
habitually experiencing the action of gravitation, come to con- 
* Read before the American Association for the Advancement of Science, at 
Providence, August, 1855. 
