something of its extent and regularity. But the few lamps of evening
would suggest little of the greatness of the public buildings, the
magnificent enterprise and commerce of its citizens, or the
intelligence of its scholars. Looking up to the lamps of the
celestial city, one can judge something of its extent and
regularity; but they suggest little of the magnificence of the many
mansions.

Stars are reckoned as so many degrees, minutes, and seconds from
each other, from the zenith, or from a given meridian, or from the
equator. Thus the stars called the Pointers, in the Great Bear,
are 5° apart; the nearest one is 29° from the Pole Star, which is
39° 56' 29" above the horizon at Philadelphia. In going to England
you creep up toward the north end of the earth, till the Pole Star
is 54° high. It stays near its place among the stars continually,

"Of whose true-fixed and resting quality
There is no fellow in the firmament."

_How to Measure._

Suppose a telescope, fixed to a mural circle, to revolve on an axis,
as in Fig. 21; point it horizontally at a star; [Page 61] turn it up
perpendicular to another star. Of course the two stars are 90°
apart, and the graduated scale, which is attached to the outer edge
of the circle, shows a revolution of a quarter circle, or 90°, But a
perfect accuracy of measurement must be sought; for to mistake the
breadth of a hair, seen at the distance of one hundred and
twenty-five feet, would cause an error of 3,000,000 miles at the
distance of the sun, and immensely more at the distance of the