revier 112-1/2, of Bourgeois 102-1/2, of Long Primer 89, of Small
Pica 83, of Pica 71-1/2, of English 64.

Wire ropes for the transmission of power vary in size from 3/8 to 7/8
inch diam. For from 3 to 300 horse power; to promote flexibility, the
rope, made of iron, steel, or copper wire, as may be preferred, is
provided with a core of hemp, and the speed is 1 mile per minute, more
or less, as desired. Tho rope should run on a well-balanced, grooved,
cast iron wheel, of from 4 to 15 feet diam., according as the
transmitted power ranges from 3 to 300 horse; the groove should be
well cushioned with soft material, as leather or rubber, for the
formation of a durable bed for the rope. With good care the rope will
last from 3 to 5 years.

Cannon balls go furthest at an elevation of 30 degrees, and less as
the balls are less; the range is furthest when fired from west to east
in the direction of the earth's motion, which for the diurnal rotation
on its axis, is at the rate of 1,037 miles per hour, and in its orbit,
66,092 miles.

The air's resistance is such that a cannon ball of 3 lbs. weight,
diameter, 2.78 ins. Moving with a velocity of 1,800 feet per second,
is resisted by a force equal to 156 lbs.

Bricklayers ascend ladders with loads of 90 lbs., 1 foot per second.
There are 484 bricks in a cubic yard, and 4,356 in a rod.

A power of 250 tons is necessary to start a vessel weighing 3,000 tons
over greased slides on a marine railway, when in motion, 150 tons only
is required.

A modern dredging machine, 123 ft. long, beam 26 ft., breadth over
all, 11 ft., will raise 180 tons of mud and clay per hour, 11 feet
from water-line.

In tanning, 4 lbs. of oak bark make 1 lb. of leather.

Flame is quenched in air containing 3 per cent, of carbonic acid; the
same percentage is fatal to animal life.

100 parts of oak make nearly 23 of charcoal; beech 21, deal 19, apple
23.7, elm 23, ash 25, birch 24, maple 22.8, willow 18, poplar 20, red
pine 22.10, white pine 23. The charcoal used in gunpowder is made from
willow, alder, and a few other woods. The charred timber found in the
ruins of Herculaneum has undergone no change in 1,800 years.

Four volumes of nitrogen and one of oxygen compose atmospheric air in
all localities on the globe.

Air extracted from pure water, under an air pump, contains 34.8 per
cent. of oxygen. Fish breathe this air, respiring about 35 times per
minute. The oxhydrogen lime light may be seen fro