Page:Popular Science Monthly Volume 75.djvu/529

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THE PLANET VENUS
525

cessive images of what is contained by the slit are presented arranged according to their wave-lengths. In practise the rays of light from the slit enter a small telescope called the collimator, and are there rendered

Sketches of the Planet Venus.
Sketches of different observers showing agreement, made at Tacubaya, Mexico, on February 7, 1897.