will be distant from the zenith point by four times that quantity,
_i. e._ by 52@ 41' 20'', a space which corresponds to the path
which she will describe during the entire journey of the projectile.
But, inasmuch as it is equally necessary to take into account the
deviation which the rotary motion of the earth will impart to the
shot, and as the shot cannot reach the moon until after a deviation
equal to 16 radii of the earth, which, calculated upon the moon's
orbit, are equal to about eleven degrees, it becomes necessary to
add these eleven degrees to those which express the retardation of
the moon just mentioned: that is to say, in round numbers, about
sixty-four degrees. Consequently, at the moment of firing the
visual radius applied to the moon will describe, with the vertical
line of the place, an angle of sixty-four degrees.

These are our answers to the questions proposed to the
Observatory of Cambridge by the members of the Gun Club:

To sum up--

1st. The cannon ought to be planted in a country situated
between 0@ and 28@ of N. or S. lat.

2nd. It ought to be pointed directly toward the zenith of the place.

3rd. The projectile ought to be propelled with an initial
velocity of 12,000 yards per second.

4th. It ought to be discharged at 10hrs. 46m. 40sec. of the 1st
of December of the ensuing year.