346 STONE. 
little piece of iron driven into a stone, with a 
force which a child might exert, the largest 
vessels might be moored,— that, by the same 
means, masses of granite might be nailed as it 
were together, with a force which could hardly 
be overcome, and rocks suspended as by a touch 
in the air.” 
Another facile contrivance for both lifting and 
removing large landfast boulders is a modifica- 
tion of the well-known sling-cart,—a machine 
which seems to have been first brought out at 
Woolwich, and was long ago used there for the 
removal of heavy ordnance, and was afterwards 
employed at Arbroath for the removal of the 
large stones used in the erection of the Bell-Rock 
lighthouse, and has of late years become common 
in the constructing of all sorts of huge masonry and 
great public works. The modification of this ma- 
chine used for lifting and removing landfast boul- 
ders, andinvented by Mr. W. F. Robertson of Hazle- 
head in Aberdeenshire, is described as follows :— 
“ The carriage-wheels are about 74 feet in height, 
to admit of the stone being freely suspended un- 
der the axle, and are defended by two or three 
concentric slender rings of iron, attached to the 
inward face of the wheels, to prevent the stone 
from chafing the spokes. The shafts are con- 
nected by cross frame-work, after the construc- 
tion of the common open cart, with the excep- 
tion of the main bar, which in this case is made 
very strong, and to which the axle of the car- 
riage is attached. On the upper side of the main 
bar is placed the frame-work of the crab: this 
consists of two cast-iron cheeks, strongly bolted 
to the main bar, and carrying a toothed wheel, 
with a drum or barrel, on which the purchase- 
chain is coiled. The wheel is acted upon by 
a pinion, which is turned by the application of 
manual power to winch-handles. The propor- 
tions of the machinery of the crab are such as to 
enable two men at the handles to raise a stone 
of three tons’ weight. A small platform is at- 
tached to the main bar on which the two men 
stand who work the crab. The purchase-chain, 
having one end fixed to the barrel of the crab, 
and a hook at the other end, completes the 
working parts of the machine. The auxiliary 
parts consist of a pair of common stone-shears, 
together with a sling chain of three or four yards 
in length, a pick-hammer, mattock, spades, &c. 
When a stone is to be raised, the only prepara- 
tion necessary is to expose, by digging, as much 
of it as will admit of the stone-shears getting 
hold, and, for this purpose, a small indentation 
is made on each side of the stone with a pick- 
hammer. The machine is then brought over the 
stone, the shears hooked on to the purchase- 
chain, and their hooked extremities brought to 
take hold of the stone, at the indentations made 
for that purpose ; a rest or prop is also put under 
the shafts, to ease the horse, and keep the ma- 
chine steady while loading. The crab is then 
worked by the two men at the handles, until the 
STONECHAT. 
stone is raised from its bed, and to such height 
that the sling-chain can be passed under it; the 
purchase-chain is then eased off; the shears dis- 
engaged, and the sling-chain being now brought 
to embrace the stone, is hooked to the purchase; 
and, by again working up the crab, the stone is 
elevated till it swim clear off the ground. The 
substitution of the chain for the shears is neces- 
sary, in order to allow the stone to be raised suf- 
ficiently high; for, though the shears must be 
used in the first place to raise the stone from the 
ground, their length prevents it from being raised 
so high as to admit of transportation. Thestone 
being in this manner suspended, its removal from 
the field is easy and expeditious.” Mr. Robert- 
son found that, when the stones are prepared by 
being dug about and marked for the shears, he 
was able to remove from 50 to 60 blocks, each 
weighing from one to three tons, to the boundary 
of a field of eight or ten acres in one day, and at 
an expense not exceeding one-half of what he 
incurred by any other method. The use of the 
simple plug-lewis and tackle instead of the stone- 
shears and chain would perhaps be an improve- 
ment; and the drilling of the hole for the plug 
might not, in the average, cost more than the 
digging and hammering for the stone-shears.— 
One of the most obvious of the common methods 
of dealing with large landfast boulders, as well 
as with slight, occasional, rocky protrusions, is 
to blow them to pieces with gunpowder, and re- 
move them in fragments. 
STONE. A weight of commodities. The legal 
stone is 14 pounds avoirdupois; but provincial 
stones, and stones of particular commodities, vary 
from 5 to 16 pounds. The old stone of glass is 
5 pounds; the old stone of fish is 8 pounds; the 
old stone of wool, in Herefordshire, is 12 pounds, 
—in Gloucestershire, 15 pounds,—and, according 
to statute in the reign of the seventh Henry, 14 
pounds; the old stone of beef, in London, is 8 
pounds,—in Herefordshire, 12 pounds,—and in 
the northern counties, 16 pounds; and a com- 
mon stone, both old and modern, both British 
and Irish, in the case of some particular commo- 
dities, is 16 pounds ;—and a ton of stones, long 
weight, is 21 hundreds. 
STONE. A disease. 
DER. 
STONECHAT,—scientifically Saxicola Rubi- 
cola. A British bird, of the warbler group of 
Passerinze. Its total length is 55 inches; its 
head, neck, chin, and throat are black ; its breast 
is rich chestnut; and the sides of its neck down 
to the wings are white. It resides in Britain 
throughout the year. Its nest is built on the 
ground, at the base of some low bush; and con- 
sists of moss, grass, hair, and feathers. Its eggs 
amount to five or six; and have a pale greyish 
blue colour,—the larger end minutely sprinkled 
with dull reddish brown; and each measures 
about 84 lines in length, and 7 lines in breadth. 
STONECROP. See Szpum. 
See Sronn-1n-THE- BLapD- 
