  On one of the faces of a pane of glass smear some lamp-black mixed with oil. If you place this glass, thus prepared, vertically on an engraving representing flowers, If you want to reproduce these, to fix their outlines, you have only to interpose a transparent paper, to draw along the glass pane a line in pencil and to trace over the part of the picture which terminates at the foot of the pane. Fold the transparent paper along this pencil line, and to get the whole reproduced you have only to copy over the designs just traced. The glass, which does the duty of a mirror, doubles the forms in a symmetrical way, and as it is moved new forms come to view. |
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