TELEGRAPHIC APPARATUS. 
223 
carries the whole system backwards or forwards on the tri¬ 
angular plate G. A uniform passage of the paper between the 
rollers d and c, is obtained by turning the screw k, which raises 
or lowers the nearest end of the roller 5, until a perfect 
regularity is obtained. The rate at which the paper passes, 
may be quickened or retarded by changing the line from one 
pulley to another. The rate of the paper can also be regulated 
by means of the commutator x, which determines the speed of 
the revolutions of the mouse mill. 
Adjustment of the siphon and the signal coil. —Siphons are 
easily made as follows : Take a glass tube one quarter inch 
in diameter and of a thickness equal to about one-sixth of its 
diameter ; in an ordinary gas-flame heat about three-quarters 
of an inch of the tube near the middle, turning it round 
carefully. When the glass is sufficiently soft, withdraw the tube 
from the flame and draw it out until its diameter is reduced to 
the size desired. Cut the fine tube thus obtained into lengths 
of four inches. To make one of these tubes into a siphon, it 
is only necessary to apply a lighted match at the proper point 
until the free part has curved down, to be nearly at right 
angles to the part held in the hand. The tube may also be 
bent into the shape shown at e (fig. 158) leaving the longer 
branch about two inches long. 
The siphon thus prepared is placed in position upon an 
aluminium saddle s (e, fig. 158), and fixed with a little wax by 
a warmed spatula. 
To fix or remove the siphon, the piece m m (b, fig. 158) 
must be raised. The turn of the siphon i i rests on this piece, 
which has a curved guide of a V shape, allowing the siphon to 
be moved without disturbing the signal coil. When the 
siphon is removed from the ink fountain, the warmed spatula 
is applied to the aluminium saddle ; the wax melts and the 
spoiled siphon can be removed and another put in its place. 
To adjust the relative positions of the siphon and the signalling 
coil. —We must see, first, that the coil is freely suspended 
round the soft-iron magnetic inducer about which it has to 
oscillate ; second, that all the cocoon silk fibres are suffi 
ciently tight; third, that the normal position of the siphon is 
vertical. 
Adjustments of certain parts are required when the apparatus 
