The Mirror of Literature, Amusement, and Instruction - Volume 17, No. 487, April 30, 1831 by Various
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page 18 of 51 (35%)
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already published are an earnest of the Editor's zeal and success. The
best method of illustrating this recommendation, is to seize from the volume a few familiar effects whose causes are imperfectly understood, and thus to show how closely the spread of science is identified with civilization and the common comforts of social life:-- _Deceptive appearance of Waves_ If we observe the waves continually approaching the shore, we must be convinced that this apparent motion is not one in which the water has any share: for were it so, the waters of the sea would soon be heaped upon the shores, and would inundate the adjacent country; but so far from the waters partaking of the apparent motion of the waves in approaching the shore, this motion of the waves continues, even when the waters are retiring. If we observe a flat strand when the tide is ebbing, we shall still find the waves moving towards the shore. _Ornamental Fountain Clocks._ It is the same cause (that which produces the deceptive appearance of a progressive motion in the waves of the sea) which makes a revolving cork-screw, held in a fixed position, seem to be advancing in that direction in which it would actually advance if the worm were passing through a cork. That point which is nearest to the eye, and which corresponds to the crest of the wave in the former example, continually occupies a different point of the worm, and continually advances towards its extremity.--This property has lately been prettily applied in ornamental clocks. A piece of glass, twisted so that its surface acquires a ridge in the form of a screw, is inserted in the mouth of some figure designed to represent a fountain. One end of the glass is attached to the |
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