smaller than our planet Jupiter, but shining, of course, by its own light. Its distance from Pollux, however, exceeds that of Jupiter from the sun in the ratio of about one hundred and thirty to one.

In the double star π we shall find a good light test for our three-inch aperture, the magnitudes being six and eleven, distance 22", p. 212°. The four-inch will show that k is a double, magnitudes four and ten, distance 6", p. 232°. The smaller star