he prism even of astronomical spectroscopes, however, is endless, and half. But if the refracting angle of the Prism be turned were not there, and whatever the shape of the aperture, the we cannot pretend to indicate more than a few leading downward, its blue half will be carried something lowe… … usually really do, each is sent to its own place cited is, then, of fundamental importance. Sim- by the prism, and as it there traces an out- ple as it is, perhaps none has ever been made in line of the slit through which the light enters, we shall have aperture is made, not a circular hole, but a…
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