more; its pointed end is for entrance between stones, and then the wooden handle and the unemployed elevated arm of the pick are used as two lever-arms at right angles to each other; thus motion can be had in two planes for the varying character of the pavior's work.
Such an employment is never allotted to the stone-mason's pick. The object of this is to remove chippings from stone much as the single-angled edge of an axe or an adze would do with chips from timber. It is, however, pointed and not edged, because stones are not fibrous. The weight of the iron head corresponds exactly with that of a heavy hammer, and, so far as this particular feature is concerned, the considerations in relation to hammers apply.
There are peculiarities in reference to the points of these tools. The whole of the energy of the workmen is expended upon one point (in the carpenter's axe or the wheelwright's adze this energy is distributed over an edge from four to eight inches in length), hence the rapid wear of this point, and the necessity not of frequent grinding, but of frequent reforging and retempering. Any attempt at grinding up these points would be practically unsuccessful, made as these picks usually are, because of the mass of metal required to give that penetration resulting from the sudden stoppage of heavy weights. The ordinary picks are therefore sent to the smith's to be sharpened. For this purpose they must be removed from the handle; and this has suggested forms of eye and handle which might with advantage be used with some other tools.
The axes and adzes hitherto considered have been chiefly regarded as tools for the greatest amount of heavy work to be accomplished by a workman. They are at one extreme of the scale, the other extreme being the removal of such small flakes as to become shavings of varying thickness. In progressing from great to small, the order would be from the axe or adze with its weighted head to a separation of the cutting-edge and its necessary metal, and the weight which must give the blow. Hence, in this descending scale, we reach the chisel, struck by a mallet.—Journal of the Society of Arts.
|SUBTERRANEAN STREAMS IN SOUTH CAROLINA.|
NEITHER the formations nor the phenomena described in this paper are peculiar to South Carolina, and the general subject has been frequently investigated in other limestone regions. The present writer, therefore, desires merely to offer some results of his own observation and experience as a contribution to the scientific literature of the subject.