The Wonder Book of Knowledge: The Marvels of Modern Industry and Invention, the Interesting Stories of Common Things, the Mysterious Processes of Nature Simply Explained
History
The Wonder Book of Knowledge: The Marvels of Modern Industry and Invention, the Interesting Stories of Common Things, the Mysterious Processes of Nature Simply Explained
Industrial arts -- History
_Double Burnishing._--The thickness of the silver deposited, however, is
not the only requisite to insure quality. The plating must be hard as
well as thick. This is accomplished by means of a double-burnishing
process after the article is plated and before it receives its final
buffed finish.
The first burnishing is on machines and this is followed by hand
burnishing. This process produces a hard plate.
[Illustration: 1. Steel cut to length. 2. Handle formed by 1,000-pound
blow. 3. Handle margin, or flash, removed. 4. Blade drawn out through a
pair of rolls. 5. Blade cut out to shape. 6. Knife roughed with coarse
emery. 7. Trade-mark etched. 8. After plating. 9. The finished knife.]
No matter how heavy the plate, if it is not properly burnished or
hardened after plating, the article will not give satisfaction in long
wear. When manufacturers treat their wares to as little burnishing as
possible, practically relying upon the buff alone for their finish after
plating, the result is most unsatisfactory. The buff finish looks all
right, but it does not harden the silver sufficiently and in consequence
the latter does not wear well. When the article comes out of the plating
bath the silver deposited is in a comparatively porous and “fluffy”
state. The buffing will hit the high spots but the proper process turns
the minute edges, closes the pores and makes the silver hard and
compact, vastly increasing the wearing quality.
The silver thus deposited, is absolutely pure--finer, in fact, than any
articles of sterling silver. Sterling is but .925 fine, requiring an
alloy to stiffen it, whereas silver for plating can be used .999 fine.
* * * * *
How do Chimes Strike the Hour?
Chimes are ordinarily produced mechanically by the strokes of hammers
against a series of bells, tuned agreeably to a given musical scale.
The hammers are lifted by levers acted upon by metallic pins or wooden
pegs stuck in a large barrel, which is made to revolve by clockwork, and
is so connected with the striking part of the clock mechanism that it is
set in motion by it at certain intervals of time, usually every hour or
every quarter of an hour.
The chime mechanism is sometimes so constructed that it may be played
like a piano, but with the fist instead of the fingers.
[Illustration: _Courtesy of the Niagara Falls Power Co._
NIAGARA ELECTRIC TRANSMISSION LINE
Tower supporting high tension transmission cables of long span crossing
of Niagara River between Buffalo and Fort Erie, Canada.]
How is Electricity Brought into a House?
The electric transmission of power is effected by employing the source
of power to drive a machine called a dynamo, which generates an electric
current.
Public-domain text, read in full here on John Shaqi.
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