It is a well known, but not less remarkable fact, that if the tip of
an exceedingly small tube be dipped into water, the water will rise
spontaneously in the tube throughout its whole length. This may be
shown in a variety of ways; for instance, when a piece of sponge,
or sugar, or cotton is just allowed to touch water, these substances
being all composed of numberless little tubes, draw up the water,
and the whole of the piece becomes wet. It is said to _suck up_ or
_imbibe_ the moisture. We see the same wonderful action going on in
nature in the rising of the sap through the small tubes or pores of
the wood, whereby the leaves and upper portions of the plant derive
nourishment from the ground.
This strange action is called "capillary," from the resemblance the
minute tubes bear to a hair, the Latin of which is _capillus_. It is,
moreover, singular that the absorption of the water takes place with
great force. If a dry sponge be enclosed tightly in a vessel, it will
expand when wetted, with sufficient force to burst it, unless very
strong.
London Water Supply.--The quantity of water consumed in London
amounts to about 145,000,000 gallons a day. If this quantity could be
collected together, it would form a lake 700 yards long, 200 wide, and
with a uniform depth of 20 feet.
A Protection for Embankments.--Engineers often have considerable
trouble with the loose soil of newly-made embankments, so apt to slip
or be washed away before they are covered with vegetation. According
to a French railway engineer, the best plan is to sow the banks with
the double poppy. Several months elapse before grasses and clovers
develop their feeble roots, but the double poppy germinates in a
few days, and in a fortnight has grown sufficiently to afford some
protection to the slope, while at the end of three or four months the
roots, which are ten or twelve inches in length, are found to have
interlaced so as to retain the earth far more firmly than those of any
grass or grain. Although the double poppy is an annual, it sows itself
after the first year.
A Cheap Concrete.--A kind of concrete made without cement is composed
of 8 parts of sand, gravel and pebbles, 1 part of burnt and powdered
common earth, 1 part of pulverized clinkers and cinders, and 1-1/2
parts of unslacked hydraulic lime. These materials are thoroughly
incorporated while dry into a homogeneous mixture, which is then
wetted up and well beaten. The result of this is a hard and solid
mass, which sets almost immediately, becoming exceedingly strong after
a few days. It may be made still stronger by the addition of a small
proportion--say 1 part--of cement.
Marking Tools.--To mark tools, first coyer the article to be marked
with a thin coating of tallow or beeswax, and with a sharp instrument
write the name in the tallow. Clear with a feather, fill the letters
with nitric acid, let it remain from one to ten minutes, then dip
in water and run off, and the marks will be etched into the steel or
iron.
How to Prevent Chisel Handles Splitting.--All carpenters know how soon
the butt-end of chisel handles split when daily exposed to the blow
of a mallet or hammer. A remedy suggested by a Brooklyn man consists
simply of sawing or cutting off the round end of the handle so as to
make it flat, and attaching by a few nails on the top of it two discs
of sole leather, so that the end becomes similar to the heel of
the boot. The two thicknesses of leather will prevent all further
splitting, and if, in the course of time, they expand and overlap the
wood of the handle, they are simply trimmed off all around.
The Largest Wheel of Its Kind Ever Made in the World.--The greatest
wheel of its kind in the world, a very wonder in mechanism, was built
for the Calumet and Hecla Mining Company of Lake Superior, Mich., for
the purpose of lifting and discharging the "tailings," a waste from
the copper mines, into the lake. Its diameter is 54 feet; weight in
active operation, 200 tons. Its extreme dimensions are 54 feet in
diameter. Some idea of its enormous capacity can be formed from the
fact that it receives and elevates sufficient sand every twenty-four
hours to cover an acre of ground a foot deep. It is armed on its outer
edge with 432 teeth, 4.71 inches pitch and 18 inches face. The gear
segments, eighteen in number, are made of gun iron, and the teeth are
machine-cut, epicycloidal in form. It took two of the most perfect
machines in the world 100 days and nights to cut the teeth alone, and
the finish is as smooth as glass. The wheel is driven by a pinion of
gun iron containing 33 teeth of equal pitch and face and runs at a
speed of 6OO feet per minute at the inner edge, where it is equipped
with 448 steel buckets that lift the "tailings" as the machine
revolves and discharges them into launders that carry them into the
lake. The shaft of the wheel is of gun iron, and its journals are 22
inches in diameter by 3 feet 4 inches long. The shaft is made in three
sections and is 30 inches in diameter in the center. At a first glance
the great wheel looks like an exaggerated bicycle wheel, and it is
constructed much on the same principle, with straining rods that run
to centers cast on the outer sections of the shaft. The steel buckets
on either side of the gear are each 4 feet 5-1/2 inches long and 21
inches deep, and the combined lifting capacity of the 448, running at
a speed of 600 feet per minute, will be 3,000,000 gallons of water
and 2,000 tons of sand every twenty-four hours. The mammoth wheel is
supported on two massive adjustable pedestals of cast iron weighing
twelve tons each, and its cost at the copper mines before making a
single revolution, $100,000.
Strength of Brick Walls.--The question of strength of brick walls is
often discussed, and differences of opinion expressed. The following
is one of the rules given:--For first-class buildings, with good
workmanship, the general average should not exceed a greater number of
feet in height than three times its thickness of wall in inches, and
the length not to exceed double the height, without lateral supports
of walls, buttresses, etc., as follows for safety: