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jumping till his head nearly touched the ceiling of the room, about eight feet high. When, afterwards, asked why he brandished his stick, as if he had been going to fight, he replied, that he imagined there was a beautiful and extensive scene before him, which he wished to approach; but was prevented by the company around him, and, therefore, was obliged to clear his way, like a policeman when keeping off a crowd. The writer has, also, seen a female rapt into perfect ecstasy in consequence of the feelings she experienced, expressing her emotions in the most poetic exclamations, and tossing her shawl, her head-dress, and her slippers, from her as unworthy of attention, and altogether regardless of the looks and opinions of surrounding spectators. But, in order that this gas may produce its full effect, it requires some attention and dexterity in breathing it. The nostrils must be stopped, and no atmospheric air, if possible, should be allowed to mix with the nitrous oxyde. For want of attending to such precautions, some persons who attempt to breathe it, never feel its peculiar effects.

It has been ascertained from various experiments, particularly from those made by the late sir Humphrey Davy, that the nitrous oxyde produces a somewhat similar effect upon insects, and other animals, which are found to jump and caper about in a frolicsome manner, as if highly delighted, when immersed in this

gas.

These, and other effects, arising from the breathing of this very singular fluid, show us with what ease the Almighty could produce in us either the most delightful or the most painful sensations, merely by a slight modification or change of the principles of which the atmosphere is composed. Certain combinations of oxygen and nitrogen gas would produce a fluid, which would inflict the most excruciating pain, and destroy the corporeal system in a few minutes. Sulphuric acid, or aquafortis, a most deadly fluid, when taken into the mouth or stomach, is composed of seventy-five parts oxygen and twenty-five parts nitrogen, which is only a different proportion of the same ingredients which constitute the air we breathe. Were, therefore, our atmosphere composed of such a proportion of these two gases, it is easy to foresee the fatal consequences which would result from breathing such a fluid. On the other hand, we may learn how an intelligent mind connected with a 'corporeal frame, somewhat analogous to ours, may be preserved in a state of uniform cheerfulness, and even of exquisite delight, by breathing an atmosphere somewhat similar to that of the nitrous oxyde. In other worlds, where the inhabitants have retained their original integrity, this may be the case. The other planets of our system or of other systems, although encompassed with atmospheres may have them of very different qualities from ours, as to their transparency, their refractive and reflective powers, and the influence

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they produce on the mental and corporeal constitution of their inhabitants. Our atmosphere exhibits evident marks of Divine wisdom and benevolence; but it is adapted to inan considered as in a state of depravity and imperfection, and appointed to a short mortal existence, and is not fitted to preserve him immortal existence in the present state, as was probably the case when this world was first arranged, and when man proceeded from the hands of his Creator as a holy being.

The next component part of the atmosphere is nitrogen gas, or what is sometimes termed azote. It is chiefly distinguished by its negative qualities. In the first place, no combustible body will burn in it; for, if a burning candle be immersed in a jar filled with nitrogen, it will be extinguished as instantaneously as if plunged in water. If a lighted taper be put into a close vessel full of common air, it will burn till all the oxygen be consumed, after which, as nothing but nitrogen remains, it will instantly go out. In the next place, it is incapable of supporting animal life ; for, if any living being be obliged to respire it, it drops down dead almost instantaneously; and, from this circumstance, it derived the name of azote, which signifies life-depriver. It is this gas which passes from the lungs at every expiration ; and, were we to breathe it again, without any mixture of other air, we should be instantly suffocated. But, being lighter than atmospheric air, it rises above our heads, and enters into new combinations. It is

owing to the presence of this gas, rising from several hundreds or thousands of lungs, that candles burn so dimly in the higher parts of crowded churches and assemblies. It is, therefore, a striking consideration, that nearly fourfifths of the air we breathe consist of this noxious and destructive fluid. But, though it is destructive to animal life, it forms an important element in the system of nature : it enters extensively into combination with other substances; and its existence in such a large quantity is a chief distinction between the constitution of animal and vegetable matter. It likewise exists in the products of several vegetables, and appears to be favourable to plants and flowers, which vegetate freely when surrounded with nitrogen. This gas is permanently elastic, transparent, colourless, and inodorous. Its specific gravity is 0.9748, that of common air being 1.0000; and one hundred cubic inches of it weigh about thirty grains. It slightly tinges delicate blue colours with green.

The other ingredient mentioned as forming a small portion of the atmosphere, is carbonicacid gas, or what was formerly called fixed air. This gas constitutes about a hundredth, or, according to some chemists, about a thousandth part of the atmosphere. It is found in a state of combination with limestone, chalk, marble, manganese, and other substances, from which it may be extracted by the application of heat, or of the mineral acids, and in considerable abundance in mines, caves, the bottom of wells,

in wine-cellars, brewers' vats, and in the neighbourhood of lime-kilns. It is invisible and elastic, and is the heaviest of all the gases, being considerably heavier than common air; and, therefore, may be poured from one vessel to another, like water. Its specific gravity is 1:5123, that of common air being reckoned 1.0000, so that its gravity is more than one and a half that of atmospheric air. One hundred cubic inches of oxygen weigh nearly thirty-four grains, while one hundred cubic inches of carbonic acid weigh more than fortysix and a half grains. It is this gas which has deprived of life many individuals who have descended into deep wells which had been long shut up from the air, and which produces so many ravages in coal-mines, under the name of the choke-damp; for it is almost instantaneously fatal to all animals that breathe it. Wherever it is found, it always occupies the lowest place, on account of its superior weight; and, therefore, in those caves where it abounds, a person may walk erect without danger; but, were he to lie down, he would be instantly suffocated. The Grotto del Cani, or the Dog's Grotto, in Italy, is well known. It is an artificial cave, in which there is a constant natural exhalation of carbonic-acid gas. The following feat is shown to strangers:-a man carries in a dog, and places him on the floor; the dog, if left long enough, dies; but the man is not affected; for the carbonic-acid gas, by its weight, occupies the lowest stratum of about eighteen inches

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