ELECTRICITY AT the Paris Exposition.--Electricity will play a large
part at the Paris Exposition of 1900, says the Revue Technique. No
less than 15,000 h.p. will be used for lighting and 5,000 h.p. for
furnishing electric power to the various parts of the grounds. As far
as possible all the machinery exhibited will be shown at work and for
this purpose electric conductors will be laid down to all points on
the grounds. The boiler plant will be located at the end of the Champ
de Mars, and will occupy two spaces of 130 X 390 feet each, one being
devoted to French boilers and the other to those of foreign makers.
This plant will be in itself a very interesting exhibit. It is
proposed to provide a capacity for evaporating not less than 440,000
pounds of water per hour.
AN INTERESTING little plant in which the rise and fall of the tides
is used as motive power for the generation of electricity is described
in L'Electricien. Near Ploumanach, on the northern coast of France,
where the tides have a daily range of 39 feet, a small fish pond
separated from the sea by a dike is arranged with gates so that at
high tide the water flows in and fills it, the gates closing
automatically when the tide recedes. The machinery of an old grist
mill is used to operate a small dynamo, which charges a storage
battery and furnishes light for the fish industry there. Another wheel
in the same mill works an ice making machine, the whole being under
the charge of one man. It is stated that the total daily expense for
generating about 2,000 horse power hours is only $2.
PEAT BOGS as generators of electrical power are suggested by Dr.
Frank in Stahl und Eisen. He says that the great peat bogs of North
Germany may be thus utilized, and figures that one acre of bog,
averaging 10 feet in thickness, contains about 1,000 tons of dried
peat, or 313,000 tons per square mile; and 430 square miles would be
equivalent in heating power to the 80,000,000 to 85,000,000 tons of
coal annually mined in Germany. The bogs of the Ems Valley alone cover
13,000 square miles; and Dr. Frank proposes the erection in that
district of a 10,000 horse power electric station, which would yearly
consume 200,000 tons of peat, or the product of 200 acres. He would
use the electrical energy on the Dortmund and Emshaven Canal, and for
the manufacture of calcium carbide.
THE SUCCESS attending an application of electric towing on the
Burgundy Canal was such that two new applications of electricity to
canal haulage and also for barge propulsion were made last year in the
neighborhood of Dijon, on the same canal, under the superintendence of
M. Gaillot, Ingénieur des Ponts et Chaussées. In the method of
haulage, says The London Engineer, the receptor dynamo is mounted on a
tricycle, to which the name of "electric horse" has been given, and
which, running on the towing path, takes its current from an air line
consisting of two wires, mounted five meters (nearly 17 feet) above
the surface. This "horse," which weighs two tons, and is guided by a
driver mounted upon it through the front wheel, proceeds on the towing
path like a traction engine; and the boats are connected with it by a
rope, with automatic disengaging gear, in case the force of the stream
or a gust of wind should drive a boat backward. Speeds of from 1,990
to 4,240 meters (mean 3,319 yards) were obtained with the electric
horse, towing from three to four boats, so that it is more suitable
than the electric propeller for towage in rivers or very long reaches;
but it requires a driver, while the propeller, with which speeds of
from 2,150 to 4,240 meters (mean 3,406 yards) per hour were obtained,
is worked by the bargee on board his boat. The towing path is not
worn, and there is no occasion for a tow rope, which always causes
difficulty when two boats cross one another. M. Maillet and M.
Dufourny, Belgian Ingénieurs des Ponts et Chaussées, who watched the
trials, conclude that a practical solution of the question depends
upon the cost of producing the motive power; but they also consider
that horse haulage on canals will soon be superseded by mechanical
traction, based on the use of an automotive tricycle, working with
petroleum or some other hydrocarbon, and capable of running on the tow
path without requiring any fixed plant.
IT HAS long been known that feathers and hair are electrical bodies,
but until recently we have had little information about their
electrical properties or the conditions in which these properties are
manifested. Most of these phenomena were first observed by Exner, and
in the work of Dr. Schwarze are found collected a mass of facts that
cannot fail to interest the physician and the biologist; besides, we
find there a description of Exner's apparatus which was used by
Schwarze in most of his experiments on electrical phenomena of this
kind. By the side of gold leaf electroscopes we see a feather
electroscope, which is fastened to its support by means of a silken
thread. A feather waved through the air is positively electrified,
while the air itself seems to be charged with negative electricity....
Two feathers rubbed together in the natural position are so
electrified that their lower surface is negative and the upper
positive.... These experiments and others still have been utilized to
study the vital relations of animals and the biological signification
of these phenomena. Most feathers stick together and remain so even
after being dried; if they then are waved through the air, the barbs
of the feather separate, owing to differences of electrification. No
bird needs to attend to its plumage at the end of a long flight, for
while the large feathers are positively electrified by friction
against the air, the white down has become negative, and so there is
attraction between it and the feathers. Another consequence of this
production of electricity during flight is that during winds, even the
most violent, the plumage does not become ruffled, but rests tightly
against the bird's body, for in this case the wing feathers, which
overlap, rub against each other and become electrified in contrary
senses. If the bird flies toward the ground, flapping its wings, it
compresses the air below them, and, supposing that the wing feathers
can bend aside, the experiments of Exner show that by the friction the
upper side of one feather and the lower side of that which is just
above are electrified oppositely, the more powerfully as the rubbing
is greater, which always causes them to resume the normal
position.--L'Electricien.
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