and universal flash, or "sheet lightning," appears to result from a discharge which is more perfectly concealed.

The bright flashes which occur during summer and autumnal evenings, unaccompanied by thunder, are of this kind, and it is supposed that on account of their vast distance from the earth, that the sound of the thunder must be lost in its passage.

"The appearance of the heavens during a thunderstorm, the manner in which the clouds assemble, and attract and repel each other, the circumstance of their rising against the wind, and traversing the upper regions of the atmosphere in a variety of contrary directions, are phenomena which it is not difficult to explain by reference to the general laws of electricity."

Many of these have been discovered by the great philosopher of the present day, and regarding his extraordinary knowledge of Electricity and Chemistry, it has been justly said, that, "in point of originality in devising experiments, skill in carrying them into effect, and perspicuity in tracing out and unraveling the complicated relations of the new truths which are elicited, he stands, if not unrivaled, at least unsurpassed."

Upon known laws of electricity, as excited in the laboratory, the peculiar fringed appearance of a thundercloud may be explained, and also the irregular portions which it projects towards the earth, whilst its upper surface is generally smooth, and well-defined.

"We sometimes observe that a number of such clouds of small dimensions, coalesce into a larger one, moving swiftly in all directions, and darting flashes from one to the other, whilst the wind rises and often blows in squalls; the lightning is more frequent as the clouds aggregate,

and a great expanse of the heavens often appears in an almost continuous blaze of light; the thunder at first rumbling in the distance, now approaches with various roaring and rattling sounds, and the rain often falls in torrents.

"If we watch a severe thunder-storm from the beginning to the end, we observe a singular variety in the appearance of the flashes; the scene is sometimes rendered awfully magnificent, by their brilliancy, frequency, and extent, darting sometimes in broad, well-defined lines from cloud to cloud, and sometimes shooting towards the earth, they are often zigzag and irregular, and sometimes are said to appear as a large and rapidlymoving ball of fire, an appearance usually designated by the uninformed, 'a thunderbolt,' and erroneously supposed to be attended by the fall of a solid body."

Thus the nodular masses that are so frequently found on the sea beach, at the foot of chalk cliffs, are called "thunderbolts," yet they have not fallen from the heavens, but from the cliffs, and when chemically examined, are found composed of sulphur and iron; they are "sulphurets of iron," therefore, and if two masses be violently struck against each other, sparks of fire appear, in consequence of the heat of the blow or collision having enabled both elements to attract oxygen from the air and burn; thus fire was anciently obtained, and the name of "pyrites," or "fire-stone," was likewise conferred upon the supposed "thunderbolt." But let us continue our investigation of the "thunder-storm."

"The voice of the Lord is upon the waters: The God of glory thundereth: The Lord is upon many

waters."

"The voice of the Lord is powerful; the voice of the Lord is full of majesty."

In such sublime and rapturous exhortation to the princes of the earth, does the Psalmist set forth the glory of the Omnipotent Ruler of the storm; and regarding its awful and astounding grandeur, no man can either feel, or feign indifference; yet he does well, that instead of indulging in morbid fear, and of communicating it to others, endeavors to calm such emotions, by reflecting and expounding that the will of God directs the storm, to remind us of our insignificance, which, in the pride of our knowledge, and the height of our abundance, we are but too prone to forget.

It is, however, the imperative duty of every man to exercise his utmost reasoning and inventive faculties for guarding his life, and the lives of others, against the physical power of the lightning, and not with impiety and presumption to defy the storm.

In the open air, shelter should not be sought immediately under a tree or building, for should they be struck, such a situation is particularly dangerous, if not fatal; the distance of twenty or thirty feet from tall trees, or lofty buildings, is, on the contrary, an eligible situation; for should a discharge take place, these prominent bodies are most likely to receive it, and the less elevated bodies in their vicinity may therefore escape uninjured.

It is quite essential, during a thunder-storm, to avoid every considerable mass of water, and even the streamlets that may have resulted from a recent shower; for these are all excellent conductors, and the height of a human being when near them, might probably determine the discharge of lightning; shelter under the arch of a bridge is a comparatively safe situation.

The conductors and imperfect conductors through which lightning directs its course when it strikes a building, are generally the metallic appendages of the walls and partitions; the most secure situation is therefore in the middle of the room, especially when standing on a hair mattress, or even a thick hearth-rug; and if a bed be drawn into the middle of the room, it will afford perhaps the safest of all situations.

The part of every building least likely to receive injury is the middle story, as the lightning does not always pass from the clouds to the earth, but occasionally from the earth to the clouds, a phenomenon called the "returning stroke;" hence it is useless to take refuge in the lowest story or in a cellar.

Many instances are recorded in which the basement story has been the only part of a building that has sustained severe injury, the lightning being weakened as it ascended.

Whatever situation be chosen, any approach to the fire-place is most dangerous; for the heated air, or even the soot in the chimney, are conductors sufficiently good to determine the course of the lightning flash, especially as they are in immediate connection with the excellent conducting iron work of the grate, fender, and fire-irons; the same caution is necessary with respect to gilt furniture, bell-wires, and moderately extensive metallic surfaces of every description.

It is likewise exceedingly dangerous to approach a window for the purpose of closing its shutters, if they have large iron bars or bolts for fastenings; an instance is known of a shock having been suddenly experienced by a female endeavoring to bar a window during a severe discharge of lightning; the effect lasted a considerable

time, but fortunately did not prove fatal. In a carriage, the precaution of keeping at some inches distance from its sides or back is also advisable.

These particulars have been enumerated from a desire "to supply what useful information the present state of our knowledge may afford, and to diminish that anxiety and fear by which the minds of many are oppressed during the occurrence of these magnificent but awful phenomena."

The operation of mysterious agents has always considerable effect on the human mind; and by raising a host of unreal terrors, may suspend the action of its best energies; but when we are enabled to ascertain something regarding the nature and influence of the powers which surround us, we are prepared to meet their effects with feelings equally remote from vain confidence and useless fear; and are thus enabled to avoid their dangers effectually and without agitation.

"Where persons have been killed by lightning, it has generally come upon them so suddenly as to leave no time for precaution; though it must also be admitted that some have suffered from foolishly ridiculing the idea of danger, and wantonly exposing themselves to the storm, walking out to admire its grandeur, or insisting upon opening the windows to look out and observe it, or standing under a tree for shelter.

"A severe thunder-storm is always an awful and dangerous phenomenon; and while, on the one hand, it is the extreme of folly to neglect common precaution, or to ridicule those that are alarmed, it is, on the other, equally weak to give way to unfounded apprehension." As the important discovery of Oxygen was made by the employment of the simple form of a "bird-fountain,"