successive appearances. At first it is seen as an inverted cone, either straight or slightly curved, extending downward from a dark cloud to which it seems to be attached. As the cone approaches the surface of the water, the latter becomes violently agitated, and, rising in spray or mist, is whirled round with a rapid motion. As the cone descends lower the spray rises higher and higher, until both unite, and a continuous column is formed extending from the water to the clouds.

The spout is now complete, and appears as an immense tube, possessing both a rotary and progressive motion; bending and swaying under the action of the wind as it advances on its course.

When the observer is near, a loud, hissing noise is heard, and the interior of the spout seems to be traversed by a rushing stream.

After continuing a short time the column is disunited, and the dark cloud gradually drawn up; for a while a thin, transparent tube remains below, but this at last is also broken, and the whole phenomenon then disap pears. These successive changes are represented in figures 9, 10, 11, which are taken from sketches of waterspouts actually seen.

What are its successive appearances?

152. FACTS. A water-spout occurred at Cleveland, Ohio, in September, 1835, which, from the description,

Describe the one which was seen at Cleveland.

nomenon.

well illustrates the origin and characteristics of this phe"A heavy storm-cloud, driven by a north. west gale, was met by a strong opposing current; when an arm of the cloud appeared to drop down, and drag the waves up towards the sky. The whirling and dashing of the spray at the surface of the lake, and the column of water and mist extending, in a tall and tortuous line, to the cloud, were so well defined as to excite the admiration of all who observed them. At the expiration of about seven minutes, the north-wester triumphed, and swept the cloud to the south-east of the city."

153. The water-spout does not always pass through the various changes that have been detailed; sometimes the upper portion only is developed, depending from a mass of black clouds, like a huge, tapering trunk, without ever reaching the water; at other times, nothing is seen but the cloud of spray and mist that forms the base. On the voyage of the Exploring squadron from New Zealand to Tongataboo, a spout was beheld in the act of forming, at the distance of about half a mile. A circular motion was distinctly perceived, the water flying off in jets from the circumference of a circle, apparently fifty feet in diameter. A heavy, dark cloud hung over the spot, but no descending tube appeared, nor was there any progressive motion. In a short time the cloud dispersed, and the surface of the sea resumed its former

state.

154. It is by no means uncommon for several waterspouts to appear at the same time. In May, 1820, Lieutenant Ogden beheld, on the edge of the Gulf stream, no less than seven in the course of half an hour: varying in their distance from the ship from two hundred yards to two miles.

155. DIMENSIONS. The diameter of the spout at its base ranges from a few feet to several hundred, and its

Does the water-spout always undergo these changes?

Under what forms is it sometimes seen?

How many have been seen at once?

What is the breadth and height of water-spouts ?

altitude is supposed by some to be at times as great as a mile. In the account given by the Hon. Capt. Napier, of a spout which he beheld in 30° 47′ N. Lat., and 62° 40 W. Lon., the diameter was judged to be 300 feet; and the height of the column to the point where it entered the hanging cloud, was computed, from observations taken by the quadrant, to be 1720 feet, or nearly one-third of a mile.

156. POPULAR ERROR. It is a common belief, that water is drawn up by the action of the spout into the clouds; but there is no proof, whatever, of a continuous column within the whirling pillar, and the fact, that the water, which sometimes falls from a spout upon the deck of a vessel at sea is always fresh, sufficiently refutes the idea. The torrents of rain, by which this phenomenon is often accompanied, can be fully accounted for by the rapid condensation of vapor that occurs, when the warm, humid air of the sea flows inward to the vortex of the whirl, and there combines with the cold air of the upper regions of the atmosphere, which descends to fill the partial void. From this union the electric phenomena of water-spouts arise, and the violent hail-showers that at times prevail; the mode, however, in which they originate, will be explained hereafter.

When a vessel is in the vicinity of water-spouts, cannon shots are usually fired for the purpose of destroying them; lest the vessel should be injured if a spout were to pass over it. It is not improbable that such an effect may be produced when the spout is either struck by the balls, or violently agitated by the concussion of the air arising from the discharges.

157. SAND PILLARS. Another form of the whirlwind is exhibited in the pillars of sand, which are not unfrequently seen in the deserts of Africa and Peru. Bruce, on his journey to Abyssinia, beheld eleven vast columns of sand of lofty height, moving over the plain at the

What popular error exists in regard to this phenomenon?

For what purpose are cannon discharged?

Where do sand pillars occur?

same time; some with a slow and majestic motion, and others with great velocity. Now, with their summits reaching to the clouds, they rapidly approached the terrified observers, and, the next moment, were borne away by the wind with incredible swiftness.

Their tops, at times, were seen separated from the main pillars, and the latter were often broken in two, as if struck by a cannon shot: the diameter of the largest was about ten feet.

While Mr. Adanson was crossing the river Gambia, a sand-whirl, twelve feet in breadth and two hundred and fifty in height, passed within forty yards of his boat.

158. The same phenomena are seen upon the Peruvian coast. "The sand," says Dr. Tschudi, "rises in columns from eighty to one hundred feet high, which whirl about in all directions, as if moved by magic. Sometimes they suddenly overshadow the traveler, who only escapes by rapid riding."

159. BENEFICIAL EFFECT OF WINDS. The utility of winds must be evident to all. By their aid vast oceans are crossed, and the products of distant climes wafted from shore to shore. Different nations are linked together by social and commercial ties, the blessings of civilization diffused, and the glad tidings from a better world borne to every land.

The growth and decay, both of animal and vegetable life, vitiates the atmosphere, and renders it unfit for respiration; but the winds prevent the deadly effects that would flow from this source, and the air becomes pure and salubrious, from its constant circulation.

Even the fierce tempest may be a messenger of mercy, by sweeping from the air the seeds of pestilence and contagion.

The advantage of winds in distributing moisture to the earth, will be seen in the following pages.

Describe those seen by Bruce and Adanson.

What does Dr. Tschudi relate?

What are the advantages arising from winds?