Scientific amusements . f the bottom of the,basinhad been raised. THE MIRAGE. Amongst the optical experiments easy to make wemay instance those relating to the curious phenomenonof the mirage. If we warm an iron plate, and lookbeyond the column of heated air which arises from theplate, we shall see the object we are gazing at deformed,or its image will appear in a different place from the trueobject. These effects are due to the difference in thedensity of the air-strata through which the visual rayspass. This is the effect whereby the traveller in the desertis deceived when the sun is very ho
Scientific amusements . f the bottom of the,basinhad been raised. THE MIRAGE. Amongst the optical experiments easy to make wemay instance those relating to the curious phenomenonof the mirage. If we warm an iron plate, and lookbeyond the column of heated air which arises from theplate, we shall see the object we are gazing at deformed,or its image will appear in a different place from the trueobject. These effects are due to the difference in thedensity of the air-strata through which the visual rayspass. This is the effect whereby the traveller in the desertis deceived when the sun is very hot. HOW TO MAKE A FLORIN APPEAR LIKE FIVE SHILLINGSAND SIXPENCE. This experiment requires for its performance a tum- 74 LIGHT, bier, a plate, a little water, a florin, and a match. Withthese appliances we can solve the astonishing problem ofhow to make a two-shilling-piece appear like iive shillingsand sixpence. Take the florin and place it in the centre of a platecontaining water just sufficient to cover the money. Then. Fig. 6i. —Experiment of Refraction and Divergent Lens obtained wiih a Tumbler take an ordinary tumbler, and holding it upside-down,warm the interior with a lighted match. When the airwithin the tumbler has been well warmed—which will bewhen the tumbler looks steamy—place it over the florinin the plate. ^ VISION AND OPTICAL ILLUSIONS. 75 The water in the plate will ascend then into the tumblerin consequence of the contraction of the cooling air in theglass, and because of the exterior atrnospheric at the surface of the water, and you will see thatthe florin is doubled in size by refraction. You willdistinguish the florin, and a little below it will appear theimage of a coin as large as a five-shilliiig-piece. Againlook at the tumbler from the top. The bottom of itforms a lens, which gives you the reduced image of theflorin so that it resembles a sixpence in size. Thus theproblem is solved, and we have five shillings and sixpencefor our florin
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Keywords: ., bookcentury1800, bookdecade189, booksubjectscientificrecreations
