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.