Page:The wonders of optics (1869).djvu/236

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If the card be placed too close to the wall, the resulting shadows will be too dark, and the outlines too sharp; if, on the contrary, the light is placed too far off, the outlines become confused, and the proper effect is lost.

Shadows have been applied before now to the propagation of seditious ideas. "In 1817," says an esteemed French author, "one winter's night we were all sitting round the table listening to my father, who was reading aloud an interesting book of the period, when a friend of our family, who had been formerly an officer of the Empire, entered the room. He was a serious, upright, soldierly man, and wore his coat buttoned up to his chin. He had hardly replied to our salutations, when he drew a chair to the table, and made a sign with his hands and eyes that plainly indicated silence and discretion. There was something in the expression of his countenance that seemed to show that he had something mysterious in store for us, and we fully expected to hear some extraordinary news, or to see him bring out a Bonapartist pamphlet of more than usual importance. Our surprise was consequently great when we saw him slowly unscrew the top of his cane, which was turned out of boxwood, and presented nothing very remarkable either in form or material. He, however, took up a copybook which was lying on the table, placed it at a certain distance from the lamp, and then laid upon it the little piece of turned boxwood. At first we noticed nothing at all extraordinary, and he smiled at our want of intelligence, until at last my youngest brother cried out suddenly, 'Look! there's the head of Napoleon!' and truly enough, we found, on looking more attentively at the shadows of the turned knob of the cane, that their profile was that of the great exile, most correctly and clearly portrayed. The old captain's face lighted up at the sight, and the tears came into his eyes. 'We shall