dually diminished, and at half-past eight was no longer visible. The wind blew more strongly from the W.N.W. and N. W. The sky became clear, and continued so until noon.

This example shews the formation of a very simple radiation, composed of two arcs only. At first, it was incomplete or unilateral, and then complete and regular, with its two points of convergence in the horizon. It may be remarked, also, that as the streaked masses, which had constantly occupied the intermediate space between the two arcs, were dissipated, the radiation progressively dwindled away. I shall, therefore,

call this a simple and perfect radiation, beginning in the west, and terminating in the east, and having both points of convergence in the horizon. Radiations, however, may take place in complicated forms, either with segments or tracks; and this consideration has led to the following divisions:

COMPLEX RADIATIONS.-It must be remembered, that the convergence of rays into one focus constitutes a radiation; and, that, when there are two foci, which more commonly occurs, they must be in opposite parts of the sky, except only in the case of obliquity. When there are several co-existing radiations, it scarcely ever happens, that there is one of them complete. Generally speaking, they are all partial. Two complex radiations are only seldom observable-still more rarely three. In a double radiation, the rays may be thrown in different angles, which may occasion a sort of confusion in the appearance of the sky, to a person who is not familiarized with occurrences of this description. In other respects, this intersection of rays serves to distinguish a double radiation, from certain oblique radiations, whose rays are almost always continuous or in straight lines. In most cases the double radiation is contrary, that is to say, that their rays intersect each other at right angles.

Radiation with a segment.-Radiation co-exists with the segment in two principal ways. First, when the segment is used in the sense of a radiation. It frequently happens, that the rays and the segment are situate in opposite directions-or, rather there are two segments opposite to each other, with the rays in the intermediate space. And secondly, when the segment is used in a signification differing from a radiation.

In

this case, the focus of the radiation is sometimes placed above the segment, or rather the rays are interrupted, and the supposed point of convergence is in the segment itself, or in the horizon, or below the horizon. This state of the sky is susceptible of many varieties, according to the obscurity or clearness of the segment, and according to the nature of the rays.

Radiated streaks with the segment.

This state of the sky, which may offer a great number of varieties, in proportion as the segment is clear or obscure, and as the radiating tracks are contrary to the segment, or in the same construction with it, coincides with the preceeding. Of all celestial appearances, this spectacle, when unobserved by clouds, is magnificent in the extreme.

Radiation resting upon an opposite arc or streak.

We frequently observe radiations, the streaks of which hold the place of inferior rays, and we also see others which entirely rest upon an opposite streak, however elevated above the horizon.

Radiated streaks above an opposite arc.

Radiated streaks above an opposite streak.

The two last may be easily comprehended from the preceding observations.

These are the principal regular aspects of the sky. They may be considered as primitive types, by which others, equally worthy of attention, may be discovered, but which it would take up too much time to enumerate, Thus, streaks, rays, and segments, may be entire, continuous, interrupted, or united, white, dappled, fringed, &c. *

* M. Clos, Nouv. Aperçu Meteor. Paris, 1828.

INDUSTRY OF ANTS.-Those who are not deep in the technical terms of entomology, may spend many an amusing hour in studying the habits of the more ingenious insects (if we may use the epithet). The various species of ants, for example, are now busily repairing the damages which the severities of winter have produced upon their domiciles. It is surprising to observe with what expedition they construct their streets and covert-ways. Upon removing a box in my garden, in which I had sown some early annuals, I found a large colony of the brown mason ants, which commonly shelter themselves under stones or amidst grass. The box being removed in the morning, they were left exposed to the light and heat of a bright sun, which is little less offensive to them than rain or frost. The colony was too large to make an immediate retreat to a place of shelter; which, besides, it would have required some time to discover and make known by their slow method of communicating intelligence. They had no alternative, therefore, but to enlarge the galleries which they had already constructed as part of their village under the box. Impelled by the strong stimulus of necessity, therefore, and being goaded by the sun's rays, they completed their excavations, and by noon had piled up a mass of earth, which at the same time increased their interior galleries and added to their protection above. At this time scarcely a straggler was to be seen, where, a short time before, hundreds were digging and piling, with all the impress of Virgil's Carthagenians, in the Second Æniad : Some extend the wall,

Some build the citadel; the formic throng,
Or dig, or push unwieldy clods along ;

Some for their streets select a spot of ground,
Which, first designed, with ramparts they surround;
Here some design a male, while others there

Lay deep foundations.

Dryden. FOSSIL CHARCOAL ACCOUNTED FOR.-I was particularly struck with a phenomenon recorded by Dr. Richardson, the naturalist in Captain Franklin's Expedition of Discovery, respecting the shale on the coasts of the Arctic sea. This shale composed precipitous banks, which, in many places, were on fire. "The shale," adds Dr. Richardson, "takes fire in consequence of its containing a considerable quantity of sulphur, in a state of such minute division, that it very readily attracts oxygen from the atmosphere, and inflames." Nothing, I think, could explain in a more satisfactory manner the occurrence of charcoal in coal measures, and other mineral strata. In the anthracite mines of North America, for example, wood-charcoal occurs with the ligneous structure as well marked as in charcoal recently prepared.

VOLCANOES.-It is remarkable, that in the Old Continent, the principal chains of mountains contain no volcanoes, and that islands and the extremities of peninsulas are alone the seats of these; while in the New World, the immense range which runs along the shore of the Pacific Ocean, possesses more volcanoes than are to be met with in the whole of the Old Continent and its adjacent islands.