292 The Pole Star and the Pointers. (July, 
It is evident that under the above conditions the pole star 
is not pointed at directly by the pointers, nor will it be until ~ 
the stars a and 8 ascend to the east and reach nearly the 
same altitude as the pole star. 
It will be evident from the preceding demonstrations that 
the pointers point with the least exactitude towards the pole 
star when then they are west of that star and on the great 
circle nearly at right angles to the meridian. It may 
appear somewhat singular to many readers when we state 
that this appearance (for it is but an appearance) will hold 
good for our latitudes, but it would not occur to a person 
who might be situated at the North Pole. Such a statement 
may seem incorrect, but it is a truth, the reason for which © 
may be understood by the following description :— 
To a person situated at the North Pole every star in the 
heavens would appear to trace a circle during twenty-four 
hours round a point exactly over his head. Every’star, 
therefore, would appear to move parallel to the horizon. If 
these four or five stars were arranged in a _ straight 
line from the horizon up towards the zenith, these four or 
five stars would always appear to an observer at the pole to 
lie in the same straight line. The curve or arch joining 
p and R in the last diagram would appear to an observer at 
the pole a straight line rising from the horizon dire¢tly to the 
point over his head, and not a curve or arch, as it appears 
to a person in such a latitude as 52°. 
Here, then, we have the key to the peculiar fact that the 
pointers do not always appear to us to point with equal 
accuracy towards the pole star. It is because owing to what 
we may term the peculiar perspective of the sphere of the 
heavens that which appears under one condition as a straight 
line may appear under another condition as a curved line, 
and as the pointers are on the apparent sphere of the 
heavens, and alter their relative positions as regards the — 
horizon, the effects are such as we have stated them to be. 
In order to render this problem as intelligible as it should 
be, we will again refer to the course or trace of the equino¢tial 
on the sphere of the heavens, and described in an early page 
of this article. We pointed out that the equinoétial, if it 
could be marked out on the sphere of the heavens, would be 
represented by a great arch which cut the east and west 
points of the horizon, and attained an altitude at the south 
equal to go° less the latitude of the place of observation. 
This curve would remain constantly marked on the sky 
during any number of rotations. It would be evident to our 
senses that a line must be a curved line which could be 
