Proctor, Richard A.: The Great Pyramid: observatory, tomb, and temple (New York, 1883)

THE PROBLEM OF THE PYRAMIDS. 153

much it differs in declination) from another, whose
right ascension and declination have already been
determined by repeated observations with the
transit circle. Similarly, the altitude and azimuth
instrument is used in direct subordination to the
transit circle.

The astronomers who observed from the Great
Pyramid doubtless made many more observations
off the meridian than on it. They made multi-
tudinous observations of the rising and setting of
stars, and especially of their heliacal risings and
settings (which last, however, though we hear so
much of them, belonged ex necessitate to but a
very rough class of observations). They no doubt
often used astrolabes and similar instruments to
determine the positions of stars, planets, comets,
&c, when off the meridian, with reference to stars
whose places were already determined by the use
of their great meridional instrument. But all those
observations were regulated by, and derived their
value from, the work done in the Great Ascending
Gallery. The modern astronomer sees that this
was the only way in which exact observations of
the heavenly bodies all over the star-sphere could
possibly have been made ; and seeing the extreme
care, the most marvellous pains, which the astro-
nomers of the Great Pyramid took to secure good