|
Main
- books.jibble.org
My Books
- IRC Hacks
Misc. Articles
- Meaning of Jibble
- M4 Su Doku
- Computer Scrapbooking
- Setting up Java
- Bootable Java
- Cookies in Java
- Dynamic Graphs
- Social Shakespeare
External Links
- Paul Mutton
- Jibble Photo Gallery
- Jibble Forums
- Google Landmarks
- Jibble Shop
- Free Books
- Intershot Ltd
|
books.jibble.org
Previous Page
| Next Page
Page 43
The cabinet contains material for two telegraph sounders and keys
which will enable the user to establish a short telegraph line with a
single cell of battery. The armature, m, may be lifted from its pivot
so as to permit of slipping one of the coils, A, on to the round
magnetic core of the sounder. The armature is then replaced, as shown
in Fig. 14, and the small retractile spring at the rear of the
instrument is arranged to draw down the shorter arm of the armature
lever. One of the terminals of the coil, A, is connected with the
turned up pivoted end of the telegraph key, o, on the same base. The
other terminal is connected with one pole of the battery and the
contact point of the key is connected with the other pole of the
battery, as shown. By swinging the key laterally, so as to remove it
from the contact point, it will be found that every touch of the key
produces a movement of the sounder lever. To connect the two
instruments together upon a line, it is only necessary to connect the
two keys with one wire and the terminals of the two coils with another
wire, cutting one of these wires and inserting the battery.
[Illustration: FIG. 15.--MAGNETIC FIGURES.]
As soon as the operator ceases to work his instrument he should place
the key in contact with the contact point, and cause it to remain
there by slipping the end of the key under the head of the screw
provided for that purpose. The other operator can then proceed to send
his message.
Those who desire to practice telegraphy should learn the Morse
telegraphic code.
MAGNETIC FIGURES.
By arranging the coil so as to form an electro-magnet, as before
described, and holding the magnet under a plate of glass sprinkled
with fine iron filings, as shown in Fig. 15, and then sending a
current through the magnet, at the same time jarring the glass by
striking it with a lead pencil, a magnetic figure will be formed which
is sometimes called the magnetic spectrum. By connecting the terminals
of the coils diagonally with each other, and connecting the remaining
terminals with the battery, two like poles will be formed, and the
magnetic figures will have an entirely different appearance, owing to
the repulsion between the two like polarities. Different figures may
be produced by using the solenoids without the iron cores.
EXPERIMENT SHOWING THE CURRENT.
By removing the coil, A, from beneath the compass, E, and connecting
the ends of the transverse wire, a' a', with the battery Fig. 16, then
lifting the plates of the battery out of the solution and allowing the
needle to come to rest, it will be found upon inserting the plates of
the battery in the solution, very gradually, that the deflection of
the needle will increase with the increase of plate surface submitted
to the action of the battery fluid; and if, when the greatest
deflection is reached, the coils or solenoids are introduced into the
circuit, one after the other, it, will be found that each added coil
diminishes the current, as will be shown by the diminished deflection
of the needle.
[Illustration: FIG. 16.--EXPERIMENT SHOWING THE CURRENT.]
MICROPHONE AND TELEPHONE.
Take two small carbon rods, p p, if procurable, if not, use two
ordinary nails, and connect them up in the circuit of the battery; lay
them upon a thin box so that the rods or nails cross each other, as in
Fig. 17; insert the electromagnet in the circuit; move the coils out a
little beyond the ends of the cores, lay a thin iron plate over the
ends of the coils, then jar the box upon which the bars, p p, are
laid, or drop a pin upon it, or scratch it with a piece of paper, and
the sound will be heard by placing the ear against the iron plate
resting upon the coils of the magnet.
ELECTRO METALLURGY.
Dissolve an ounce of sulphate of copper in a half pint of water; add a
few drops of sulphuric acid; connect with the zinc pole of the battery
the object to be coppered. To the wire connected with the carbon
attach a small plate of copper. Hang the object and the copper plate
in the solution a short distance apart. A deposit of copper will be
quickly formed.
Previous Page
| Next Page
|
|