Letters on Natural Magic; Addressed to Sir Walter Scott, Bart.Brewster, David
History
Letters on Natural Magic; Addressed to Sir Walter Scott, Bart.
Brewster, David
Scientific recreations
Round the larger rims of three of these pulleys, viz. those on the
right hand, there are coiled three cords, which, by means of several
smaller pulleys, terminate in the upper boards of other three pair of
bellows placed on the top of the box.
The tension of each cord when it begins to raise the board of the
bellows to which it is attached, gives motion to a lever placed above
it between the axis and the double pulley in the middle and lower
region of the box. The other end of this lever keeps open the valve in
the lower board of the bellows, and allows the air to enter freely,
while the upper board is rising to increase the capacity of the
bellows. By this means there is not only power gained, in so far as the
air gains easier admission through the valve, but the fluttering noise
produced by the action of the air upon the valves is entirely avoided,
and the nine pair of bellows are wrought with great ease, and without
any concussion or noise.
These nine bellows discharge their wind into three different and
separate tubes. Each tube receives the wind of three bellows, the upper
boards of one of the three pair being loaded with a weight of four
pounds, those of the second three pair with a weight of two pounds,
and those of the other three pair with no weight at all. These three
tubes ascended through the body of the figure and terminated in three
small reservoirs placed in its trunk. These reservoirs were thus united
into one, which, ascending into the throat, formed by its enlargement
the cavity of the mouth terminated by two small lips, which rested
upon the whole of the flute. These lips had the power of opening more
or less, and by a particular mechanism, they could advance or recede
from the hole in the flute. Within the cavity of the mouth there is a
small moveable tongue for opening and shutting the passage for the wind
through the lips of the figure.
The motions of the fingers, lips, and tongue of the figure were
produced by means of a revolving cylinder, thirty inches long and
twenty-one in diameter. By means of pegs and brass staples fixed in
fifteen different divisions in its circumference, fifteen different
levers, similar to those in a barrel organ, were raised and depressed.
Seven of these regulated the motions of the seven fingers for stopping
the holes of the flute, which they did by means of steel chains rising
through the body, and directed by pulleys to the shoulder, elbow, and
fingers. Other three of the levers communicating with the valves of the
three reservoirs, regulated the ingress of the air, so as to produce a
stronger or a weaker tone. Another lever opened the lips so as to give
a free passage to the air, and another contracted them for the opposite
purpose. A third lever drew them backwards from the orifice of the
flute, and a fourth pushed them forward. The remaining lever enabled
the tongue to stop up the orifice of the flute.
Public-domain text, read in full here on John Shaqi.
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