Hepworth, Thomas Cradock, -1905 · London : Hazell, Watson, and Viney · leaf 186
174 EVENING WORK FOR was applied to this purpose more than thirty years back in connection with that extremely rough optical instrument which was known as the Solar Microscope. For nearly as … Fig. 61. long a time the electric lamp of Serrin, and a regulator known as Browning's have been used for throwing spectrum phenomena on a screen. But such experiments were seldom shown, for the trouble, expense, and mess of a forty or fifty cell battery were not to be lightly undertaken except
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