family twenty-five thousand pounds after the
loss of twenty ships, and property worth several
millions of francs taken from him by the
English. It was in the house of Madame
Chevalier, charged with the education of her
son, that Monsieur Robertson lived during
the first wild days of the French revolution.

The fee of four louis for attendance at the
lectures of Monsieur Charles, had of course
been compassed. The fame of Monsieur
Charles, because he wrote nothing, and
perhaps was not remarkable for originality,
scarcely survives in the world, but he was
famous in his day. He startled the public
by the scale on which he performed the
experiments connected with his lectures. If he
lectured on the microscope he displayed
extravagant enlargements, if his subject was
electricity he fulminated death upon some
animal. It was Monsieur Charles who first
introduced the use of hydrogen gas for the
inflation of balloons and superseded the
Montgolfiers, of which the dilatation was contrived
by fire. M. Charles, however, was content
to make in his own person but one balloon
ascent, and wondered much at the temerity of
æronauts.

The adventures of Monsieur Robertson
and the Chevalier family during the Reign of
Terror are recounted in his book, and some
of them would be worth telling if we could
afford them space. But it is another reign of
terror with which Robertson's life has most
connection—the terror of the ignorant at
shadows and hobgoblins. We must hurry on
to that. After six or seven years spent in
Paris, when he had completed the education
of M. Chevalier's son, and also increased largely
his own knowledge of physics, the old state
of health by which he had been vexed at
Liège returned, and Robertson was advised to
try Spa-waters, and residence for some months
in his native air. He therefore spent a month
at Spa and then returned to Liège, no longer
an independent capital, as it was when he had
left it, but transformed into the character of
chief town of the department of the Ourthe.

He had then for some time been engaged in
an endeavour to reconstruct the mirror with
which Archimedes when at Syracuse had
burnt the ships of the besiegers. This he
thought could be done by concentrating upon
one point the focuses of a great number of
mirrors. Father Kirker had suggested this
idea, and twenty-eight years afterwards, that
is to say in seventeen hundred and forty-
seven, Buffon had based some experiments
upon it, which were made in the month of
April in the Jardin des Plantes. In the course
of the same year too, Buffon had publicly
burnt a combustible on one side of the Seine,
by his system of a hundred and sixty-eight
reflectors, arranged on the other bank. Each
of the reflectors used by Buffon was held
by a soldier, and the hundred and sixty-
eight soldiers, manœuvred among
themselves to procure a common focus. The
ambition of Monsieur Robertson was to
produce a machine fitted with reflectors, capable
of prompt and simultaneous mechanical
adjustment, so that the sun's rays might be fired
against the enemy—into a powder magazine,
or upon the cordage of a ship, with perfect
ease. Such an invention M. Robertson
believed during his visit to Liège, that he had
at last perfected, and having constructed it
in model, he desired from the departmental
administration of the Ourthe an official
examination of it. Two gentlemen were accordingly
appointed to report on the machine, and
declared it to be most simple, able to vary its
focus within exceedingly wide limits with the
rapidity of speech, to chase with it an object
shifting its position, to adapt itself to the
course of the sun, and to do all in obedience
to touches so light and simple, that a child
after one lesson might undertake its management.
The report also pointed out the use
of such a machine not only in any time of
war, but also for the furtherance of many
arts and manufactures in which fire is
employed. Whoever desires to know how M.
Robertson contrived all this, may refer to his
book, in which he explains and illustrates by
diagrams every part of his method. He there
also gives a picture of his engine of war, as
he proposed to construct it, and to mount it
for the use of armies. There may be some sense
in the notion, or there may be none, but
certainly it is too far from the line of
tradition in this country, for whatever sense
may lurk in it, to meet with anything, but
a pooh pooh from the authorities. It will be
time enough to inquire into the matter when
our ordnance department shall have
condescended to acknowledge the use of so obvious
and powerful a weapon as the great steam-
gun. We can discuss the discharge of focuses
against the foe when we have nothing more
to say concerning shot.

The invention of M. Robertson having been
hailed with enthusiasm by the authorities in
his department, he was sent with a special
passport and some hearty notes of introduction
from the departmental government to
Paris, with orders to submit his invention to
the notice of the Directory. It so happened
that his old friend, M. Bénézech, was then in
office, and the inventor had a favourable
hearing. He was respectfully referred to the
National Institute, and that body appointed
MM. Monge, Guiton de Morvau, and Lefebvre
Gineau, to report upon his proposition. For
a long time these gentlemen neglected him,
he says; then at last they called upon him
one day towards noon, when Gineau talked a
great deal very slightingly; Guiton de Morvau
seemed to be lost in meditation; and Monge
was, for the whole time, in a fidget about the
signification of some distant drums. After
their departure, he awaited daily a report that
did not make its appearance. In the meantime,
having farther simplified his plan, M.
Robertson one evening took his model to the