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fatal efficacy of gunpowder as an agent for the destruction of human life surprised the cloistered Bacon. The mirthful disporting of the children of an obscure spectacle-maker of Middleburg, who, by placing two pieces of glass one before the other and looking through them, observed the weathercock on a neighbouring steeple to be magnified, drew the notice of the father to the fact; who, struck by the singularity of the effect, adjusted lenses on a board in brass rings, moveable at pleasure,—the first rude attempt at the telescope, the instrument which so effectually aided to establish the renown of Newton, La Place, and Herschel. The spasmodic convulsion of the limbs of a dead frog, caused by the unpremiditated contact with two plates of metal, exposed to Galvani the premises on which, by a series of successful experiments, he built up the principles of animal electricity. While many of those by which chemistry has ministered so extensively to the convenience and efficiency of medicines, by removing nauseating or pernicious substances; or to enobling the arts by disclosing previously unknown properties in vegetables, minerals, acids, or alkalis; in fixing or liberating colours; in ascertaining the composition and affinities of the different gases, have almost, as it were, obtruded themselves obliquely, and the unappropriated ideas which the surge of ever flowing time casts upon its bosom have thus allowed themselves to be drawn within the eddying verge of that circle which the enquirer has disturbed.
But to turn and view the subject in another light. There is no slender enjoyment afforded by the ready concession made by intellectual liberality to a demonstration, however startling, which stands in direct contradiction to traditional error, to the immature offspring of crude theories which we have too readily accepted from others; or to the cherished conclusions which we may have rashly drawn from ill-considered or assumed data; and the celerity with which after the evidence has been understood and assent granted to the new proposition, all pre-existing notions are displaced, and the tenacity with which the belief clings to the latter doctrine, by which the former has been supplanted, prove incontestably
