This is an exhibition in the _Cour des Capucines_, adjoining to the
Boulevard, where ROBERTSON, a skilful professor of physics, amuses or
terrifies his audience by the appearance of spectres, phantoms, &c.
In the piece which I saw, called _Le Tombeau de Robespierre_, he
carries illusion to an extraordinary degree of refinement. His
cabinet of physics is rich, and his effects of optics are managed in
the true style of French gallantry. His experiments of galvanism
excite admiration. He repeats the difficult ones of M. VOLTA, and
clearly demonstrates the electrical phenomena presented by the
metallic pile. A hundred disks of silver and a hundred pieces of zinc
are sufficient for him to produce attractions, sparks, the divergency
of the electrometer, and electric hail. He charges a hundred Leyden
bottles by the simple contact of the metallic pile. ROBERTSON, I
understand, is the first who has made these experiments in Paris, and
has succeeded in discharging VOLTA's pistol by the galvanic spark.
FITZJAMES, a famous ventriloquist, entertains and astonishes the
company by a display of his powers, which are truly surprising.
You may, perhaps, be desirous to procure your family circle the
satisfaction of enjoying the _Phantasmagoria_, though not on the
grand scale on which it is exhibited by ROBERTSON. By the
communication of a friend, I am happy in being enabled to make you
master of the secret, as nothing can be more useful in the education
of children than to banish from their mind the deceitful illusion of
ghosts and hobgoblins, which they are so apt to imbibe from their
nurses. But to the point--"You have," says my author, "only to call
in the first itinerant foreigner, who perambulates the streets with a
_galantee-show_ (as it is commonly termed in London), and by
imparting to him your wish, if he is not deficient in intelligence
and skill, he will soon be able to give you a rehearsal of the
apparition of phantoms: for, by approaching or withdrawing the stand
of his show, and finding the focus of his glasses, you will see the
objects diminish or enlarge either on the white wall, or the sheet
that is extended.
"The illusion which leads us to imagine that an object which
increases in all its parts, is advancing towards us, is the basis of
the _Phantasmagoria_, and, in order to produce it with the
_galantee-show_, you have only to withdraw slowly the lantern from
the place on which the image is represented, by approaching the outer
lens to that on which the object is traced: this is easily done, that
glass being fixed in a moveable tube like that of an opera-glass.
As for approaching the lantern gradually, it may be effected with the
same facility, by placing it on a little table with castors, and, by
means of a very simple mechanism, it is evident that both these
movements may be executed together in suitable progression.
"The deception recurred to by phantasmagorists is further increased
by the mystery that conceals, from the eyes of the public, their
operations and optical instruments: but it is easy for the showman to
snatch from them this superiority, and to strengthen the illusion for
the children whom you choose to amuse with this sight. For that
purpose, he has only to change the arrangement of the sheet, by
requiring it to be suspended from the ceiling, between him and the
spectators, much in the same manner as the curtain of a playhouse,
which separates the stage from the public. The transparency of the
cloth shews through it the coloured rays, and, provided it be not of
too thick and too close a texture, the image presents itself as clear
on the one side as on the other.
"If to these easy means you could unite those employed by ROBERTSON,
such as the black hangings, which absorb the coloured rays, the
little musical preparations, and others, you might transform all the
_galantee-shows_ into as many _phantasmagorias_, in spite of the
priority of invention, which belongs, conscientiously, to Father
KIRCHER, a German Jesuit, who first found means to apply his
knowledge respecting light to the construction of the magic lantern.
"The coloured figures, exhibited by the phatasmagorists, have no
relation to these effects of light: they are effigies covered with
gold-beater's skin, or any other transparent substance, in which is
placed a dark lantern. The light of this lantern is extinguished or
concealed by pulling a string, or touching a spring, at the moment
when any one wishes to seize on the figure, which, by this
contrivance, seems to disappear.
"The proprietors of the grand exhibitions of _phantasmagoria_ join to
these simple means a combination of different effects, which they
partly derive from the phenomena, presented by the _camera obscura_.
Some faint idea of that part of physics, called optics, which NEWTON
illuminated, by his genius and experience, are sufficient for
conceiving the manner in which these appearances are produced, though
they require instruments and particular care to give them proper
effect."
Such is the elucidation given of the _phantasmagoria_ by an
intelligent observer, whose friend favoured me with this
communication.