extremity of the brass tube. The currents induced in this wire produce a
series of sparks between the tube, L, and the rod, M, which light the
gas when the extremity of the apparatus is placed in proximity with the
burner.

[Illustration: Fig. 2. MECHANISM OR THE INDUCTION SPARK GAS LIGHTER.]

The ingenious and new part of the system lies in the mode of exciting
the induced currents. When the extremity of the tube, L, is brought near
the gas burner that is to be lighted, it is only necessary to shove the
botton, F, from left to right in order to produce a _limited_ number of
sparks sufficient to effect the lighting. The motion of the button has
not for effect, as might be believed, the closing of the circuit of the
pile upon the inducting circuit of the bobbin. In fact in its normal
position, the vibrator is distant from its contact, and the closing of
the circuit would produce no action. The motion of F produces a
_mechanical_ motion of the spring of the vibrator, which latter acts for
a few instants and produces a certain number of contacts that give rise
to an equal number of sparks. Owing to this arrangement, the expenditure
of electric energy required by each lighting is limited; and, an another
hand, the vibrator, which would be incapable of operating if it had to
be set in motion by the direct current from the pile, can be actuated
_mechanically_. As the motion of the vibrator is derived from the hand
of the operator, and not from the pile, it will be comprehended that the
latter can, everything being equal, produce a larger number of lightings
than an ordinary bobbin and vibrator.

[Illustration: Fig. 3.--INCANDESCENT GAS LIGHTER.]

Dr. Naret's _Fiat Lux_ (Fig. 3) is simpler in its operation, and cheaper