be
already anticipating the fuel of the future by such a practice.
Whether or not this is the case, it is at least satisfactory for
mankind to know that the mother earth will not fail him when he comes
to demand a substitute for coal. I may be too early even to think of
the day of extinction; but we may regard that evil day with
complacency in face of the stores of fuel husbanded for us within the
rock foundations of our planet.--_Glasgow Herald._

* * * * *

PORTABLE ELECTRIC LIGHT.

The famous house of MM. Sautter, Lemonnier & Co. takes a conspicuous
part in the Paris exhibition, and from the wide range of its
specialties exhibits largely in three important branches of industry:
mechanics, electricity, and the optics of lighthouses and projectors.
In these three branches MM. Sautter, Lemonnier & Co. occupy a leading
position in all parts of the world.

The invention of the aplanetic projector, due to Col. Mangin, was a
clever means of overcoming difficulties, practically insurmountable,
that were inseparable from the construction of parabolic mirrors; this
contributed chiefly to the success of MM. Sautter, Lemonnier & Co. in
this direction. The firm has produced more than 1,500 of these
apparatus, representing a value of nearly L500,000, for the French and
other governments.

Besides the great projector, which forms the central and crowning
object of the exhibit of MM. Sautter, Lemonnier & Co. in the machinery
hall, the firm exhibits a projector 90 centimeters in diameter mounted
on a crane traveling on wheels, in the pavilion of the War Department.
The lamp used for this apparatus has a luminous value of 6,000
carcels, with a current of 100 amperes; the amplifying power of the
mirror is 2,025, which gives an intensity of ten millions to twelve
millions of carcels to the beam.

Projectors used for field work are mounted on a portable carriage,
which also contains the electric generator and the motor driving it.

[Illustration: MILITARY PORTABLE ELECTRIC LIGHT AT THE PARIS
EXHIBITION.]

It consists of a tubular boiler (Dion, Bouton & Trepardoux system).
This generator is easily taken to pieces, cleaned, and repaired, and
steam can be raised to working pressure in 20 minutes. The mechanical
and electrical part of the apparatus consists of a Parsons
turbo-motor, of which MM. Sautter, Lemonnier & Co. possess the license
in France for application to military and naval purpo