STATICAL PHENOMENA.

Two classes of phenomena

The phenomena of our solar system divide themselves into two classes,—the Statical and the Dynamical. The first class comprehends the circumstances of the star itself, independent of its motions; as its distance, magnitude, form, atmosphere, etc. : the other comprehends the facts of its displacements, and the mathematical considerations belonging to its different positions. According to the usual analogy, the first is independent of the second; while the second could have no existence without the first. The Statical phenomena would exist if the system was immovable : while the dynamical are wholly determined by the statical conditions.

Planetary distances

The first thing necessary to be known about any heavenly body is its distance from the earth : and the difficulty of obtaining this ground for further observations is extremely great,—the smallness of the base of our triangle, and the immensity of the distance of the planet, rendering all accuracy hopeless in very many cases. Towards the middle of the last century, when it was desired to determine the horizontal parallax of the moon,—the most manageable of the heavenly bodies,—Lacaille went to the Cape of Good Hope, and Lalande to Berlin, to observe its distance at the same moment from the zenith,—that moment being appointed,—as the middle of an anticipated eclipse. The stations were so chosen as to afford a pretty accurate knowledge of the extent of the line of the base,—which was about as long a one as our globe could afford.