recover; men are oppressed with a stopped perspiration, heaviness at the breast, and sore throat, but recover with proper care.

The most dreadful winds, perhaps, are those in the deserts near Bagdad, called Samoul, or Mortifying Winds. The camels perceive their approach, and are said to make an unusual noise, and cover their noses in the sand. To escape their effects, travellers throw themselves as close on the ground as possible, and wait till the winds have passed over, which is commonly in a few minutes. Thus some escape; but those who die, have their limbs mortified.

In Italy, a wind blows, for several days, called Sirocco, which is fatal to vegetation, and destructive to the inhab itants; depressing their spirits, and suspending the pow ers of digestion, so that those who venture to eat a heavy supper, while this wind prevails, are frequently found dead the next morning. It is felt with peculiar violence at Palermo.

In the deserts of Africa, there are prodigious pillars of sand, which move with great velocity. Mr. Bruce saw several of these at once, some of which appeared to be ten feet in diameter. They began immediately after the rising of the sun, and his rays shining through them, gave them the appearance of pillars of fire.

There is a phenomenon, called the Water Spout, hanging under a deep cloud, in the form of a cone, with the vertex downward; and under it the sea boils up and rises in a conical form. These cones sometimes meet, and they generally begin to appear together; they sometimes move for a considerable space before they break. When they appear at sea, and approach a ship, it is said the sailors fire at them and break them, as it might be dangerous if they should meet with a ship and break over it. water spout is supposed to be an electrical phenomenon.

The

A Whirlwind is a wind, which rises suddenly; it is extremely rapid and impetuous, taking up all light sub stances from the earth which it meets with, and carrying them up in a spiral motion. Dr. Franklin supposes that the whirlwind and water spout proceed from the same cause. They have each a progressive and circular motion; they usually rise after calms and great heats; and

most frequently happen in warm latitudes; the wind blows, from every way, towards both; and a water spont has been known to move from the sea to the land, and to produce all the effects of a whirlwind. They are both, probably, the effects of the electrical fluid.

VAPORS AND CLOUDS.

VAPORS are raised from the surface of the moist earth and waters, the principal cause of which is, probably, the heat of the sun; the evaporation being always greatest. when the heat is greatest. The vapors, thus raised, by heat, ascend into the cold regions of the atmosphere, and form Clouds, which are of the same nature as dews and fogs upon the earth.

When the water in the air ceases to be suspended, it falls down, and the particles, uniting in falling, form drops, or Rain. If it be very cold in those regions where the rain begins to be formed, it then descends in Snow. When the drops of rain are formed, and are descending, if in their descent they pass through a region of the air cold enough to freeze them, they descend in Hail.

ELECTRICITY.

The earth and all bodies, with which we are acquainted, are supposed to contain a certain quantity of an exceedingly elastic fluid, called the Electric fluid.

Lightning is the electric fluid in the atmosphere; discharging itself, sometimes from one cloud to another, and sometimes from the clouds to the earth. This discharge occasions the ful roll, or sound, called Thunder.

A machine, fitted up with certain appertenances, for the purpose of exciting electric fluid, and making it per ceptible to the senses, is called an Electrical machine. The sudden discharge of the fluid contained in the machine, gives a painful sensation to any animal placed within the eircuit of its communication, called the Electrical Shock.

That lightning and the electric fluid are one and the same substance, has been, proved by Dr. Franklin and others. Lightning strikes the highest and most poisted. objects; rends bodies to pieces and sets them on fire; dis

sølves metals; and destroys animal life; in all which, it agrees with the phenomena produced by an electrical apparatus.

Some fishes have the power of giving shocks similar to those of artificial electricity. The torpedo, found in the rivers of South America, when touched by the naked hand, or any conductor, produces a strong electric shock. The gymnotus electricus, and some others, possess the same power. Electricity has been administered for various diseases of the human body; some of which have been relieved, and others perfectly cured.

LIGHT.

Light is that, which proceeding from a certain body to the eye produces the perception of seeing. An exceedingly small portion of light is called a Ray. A larger body of light consisting of many parallel rays, is called a Beam.

The rays of light fly with amazing swiftness, at the rate, it is computed, of 11,875,000 miles in a minute or more than a million times swifter than a cannon ball, which is computed to move 8 miles in a minute. Light is found to proceed from both animal and vegetable substances in a putrid state.

The Twilight is that faint light, which appears in the east in the morning before the sun rises, and gradually vanishes in the west after he sets.

The sun is the original source of light to our system; and though it rise and set all over the earth, yet the circumstances attending its rising and setting are very different in different countries.

In the equatorial regions, darkness comes on very soon after sunset; because the convexity of the earth comes quickly between the sun and the eye of the observer. Proceeding from the equator, the twilight continues a longer time after sunset; and, in 481° N. latitude, it continues through the night in the month of June. As we approach the poles the twilight becomes brighter and brighter, till at last the sun does not appear to touch the horizon, but is seen above it many days successively. On the other hand, in winter, the sun sinks lower and lower, till it does

not appear at all, and there is only a dim twilight, for an hour or two, in the middle of the day.

Notwithstanding the seeming inequality in the distribution of light and darkness, it is certain that throughout the whole world, there is nearly an equal proportion of light diffused on every part, abstracted from what is absorbed by clouds, vapors, and the atmosphere itself. The equatorial regions have indeed the most intense light dur ing the day, but the nights are long and dark; while on the other hand, in the northerly and southerly parts, though the sun shines less powerfully, yet the length of time that he appears above the horizon, with the greater duration of twilight, make up for the seeming deficiency.

THE HARVEST MOON.

It is a remarkable and highly beneficial circumstance, that in those countries which are at considerable distances, from the equator and the poles, the autumnal full moons rise nearly at sunset, from the first to the third quarter ;, a dispensation singularly calculated to facilitate the reaping and gathering in the fruits of the earth. This phenomenon is called the Harvest Moon. It is farther observable, that this appearance in the autumnal months is péculiar to the full moon; for though in every month, the moon for several successive days will vary the time of her rising very little; yet in the vernal months, this happens: at the time of the new moon; in the winter months, about the time of the first quarter; and in summer, at the time of the last quarter. In the latitude of 30° north, the time of the moon's rising is observed to vary only two hours in six days.

NORTHERN LIGHT.

No

The Aurora Borealis, or Northern Light, in many parts of the northern hemisphere, enables the inhabitants to pursue their occupations during the absence of the sun. satisfactory conjecture has yet been formed, as to the cause of this phenomenon. Some have supposed it to be elec-trical matter, imbibed by the earth from the sun, in thee

warm latitudes, and passing off through the upper regions of the atmosphere, to the place whence it came.

These lights commonly appear at twilight, near the horizon, of a dun color, approaching to yellow, and sometimes continue in that state for several hours, without any apparent motion. In the Shetland Isles, and other northern regions, they are the constant attendants of clear evenings, and prove a great relief amid the gloom of long winter nights; and are there called Merry Dancers. They sometimes break out into streains of strong light, spreading into columns, and altering slowly into thousands of different shapes, varying their colors, from all the tints of yellow, to the most obscure russet. They often cover the whole hemisphere, affording the most brilliant prospect. At other times, they assume the color of blood, and makea very dreadful appearance. They have generally a quick tremulous motion, which continues till the whole vanishes.

HEAT AND COLD.

The presence of the sun is one of the principal sources of heat, and its absence the cause of cold. But were these. the only sources of heat and cold, there would be, in the same parallels of latitude, the same degree of heat and cold at the same season; which is not the fact; for very hot days are frequently felt in the coldest climates and very cold weather, and even perpetual snow, is found in countries under the equator.

One source is from the earth; probably arising from a. mass of heat diffused through it, which imparted from the earth to the atmosphere, tends greatly to moderate the se verity of the winter's cold. It is probably from this in ernal heat, that snow generally begins to melt first at the bottom. Another source of heat is the condensation of: vapor, which warms the surrounding atmosphere. This condensation is frequently formed by the attraction of an electrical cloud; and hence the great sultriness often experienced before a storm.

As the earth is a source of heat, so distance from it is a source of cold and it is found in ascending the atmo i sphere, that the cold increases. The tops of the highest