MINING. 109 
upon the rocky strata in turning the auger, use is made of the carp-tongue 
or serpent-tongue auger, of the riband-shaped, furrowed, and four-cornered 
auger. For cutting into quartz, pebbles, or rubble-stone, the conical-headed 
auger answers. ‘The portions of rock bored out, and the earth, are brought 
to view by means of the soil-borer or loam-spoon, also by the salt or sand- 
borer, which is a hollow cylinder having a globular valve below. Some- 
times the shaft and boring part break in the hole, and they must be again 
drawn out. For this purpose a hook is used which catches hold of the 
bands of the shaft, and in this way it is lifted out. The same object 
is accomplished by a grappling-tool, which is screwed down in such a 
manner over the shaft broken in the hole or rope that the claws fasten upon 
the shaft or rope, which is then drawn up. 
For facilitating the operations of boring, variously constructed frames are 
used. A very good boring-frame consists of four posts for suspending the 
auger with a windlass and lifting-cams. There is a rope for suspending and 
lifting out the auger, and a swingle or balance-handle to allow the auger to 
operate by strokes. This swingle is connected with a lever, which is raised 
by means of cams on the windlass and falls back by its own weight. This 
windlass is represented in pl. 23; jig. 13a is a side view of the cams or 
short levers on the windlass. 7g. 136 is a section at azB of jig. 13c, seen 
towards the side of the windlass. /%g.13c¢ is a front view. The three 
cams or lever arms, aaa, are fixed to the axis m, and serve to make the 
lever for the swingle, or auger handle, rise and fall. cc are the cast-iron 
uprights of the frame; m, the axis on which the rope of the auger winds 
itself; on the same axis is the lift-wheel, aaa, which moves the lever of the 
boring-rod. wN is a cog-wheel which catches in the driver g; d is a set of 
pinion wheels, the teeth of which have a reversed direction, and in which 
the pawl x, which is fastened on the upper rod, is allowed to catch when it 
is desired to prevent the backward movement of the windlass. ¢ is a 
wooden wheel on which presses the brake band, e, which is drawn on to it 
by means of the lever f (jig. 130). A is a stop placed on the axis of the 
crank between the upright c and the enlargement of the axis, to keep the 
wheel in gear with the pinion. Ifthe stop / be raised, then the driver may 
be released from the cog-wheel, by shoving the axis gf through its boxes 
in the frame cc until the pinion g no longer engages the cog-wheel n. 
The usual process of boring is briefly the following. First, the surface is 
attacked by the proper boring tools. With conical-headed augers and 
chisels, the motion of the auger is by strokes, the tool being slightly turned 
round. The auger is only occasionally lifted when the borings impede its 
operation. The expense and difficulty increase rapidly with the depth of 
the hole bored, on account of the weight of the shank of the auger; for the 
last few years, therefore, ropes have been used instead of the stiff iron shanks, 
and with very good success. A tolerably high massive boring-frame, a 
windlass or vertical capstan, and lever, together with the auger rope and 
various tools for attacking the rock, are the only things needed in this 
method of boring, which is represented in pl. 25, jigs. 6, 7, 8, and 9. 
Figs. 6 and 7 represent the boring-frame, the windlass, the swingle, and the 
ICONOGRAPHIC ENCYCLOPZDIA.—VOL, IV. 44 689 
