Page:Willich, A. F. M. - The Domestic Encyclopædia (Vol. 3, 1802).djvu/115

Rh a bandage.—On the chemical effects of light, we are silent; for the opinions respecting them are not less unsettled than those concerning its nature.—The inquisitive reader will find ample information on this subject, in the writings of Dr., and also in the different volumes of the Transactions of the Royal Society.  LIGHTNING, a vivid, bright flash of fire, which suddenly appears in the atmosphere, and instantly vanishes: it is sometimes attended with heavy clouds and thunder; but often occurs while the sky is serene, especially in sultry summer evenings.

The phenomena accompanying this meteor are always surprizing; but, in many cases, truly terrific:—variofis causes have been assigned by philosophers, with a view to explain them. Some suppose lightning to arise from inflammable matter, consisting of the sulphureous and nitrous vapours exhaled from the earth, and carried into the atmosphere; whence the more fiery particles are separated, so that they explode by the concussion of two clouds, or some other cause, in various directions of a greater or less extent, according to the strength and quality of the materials. Others conjecture lightning to be formed by the fermentation of sulphureous matters with the nitrous acid. It is, however, now generally understood to be an electrical phenomenon.

In common with electricity, lightning possesses the property of burning and dissolving metals; it rends bodies, often deprives persons of sight, and sometimes extinguishes the vital principle; divests magnets of their virtues, and reverses their poles. Indeed, there is no appearance in Nature, that presents a greater diversity to the contemplative mind; for each flash is widely different from another; nor are its effects alike fatal.

When the igneous meteor exhibits a deep red colour, it is seldom accompanied with dangerous consequences; but, if the flashes be bright, pale, and in a zig-zag direction, destruction generally marks their course. The most mischievous form, however, which lightning assumes, is that of fiery balls: wherever such masses descend, they burst, and occasion extensive damage.

As lightning uniformly strikes the most elevated objects, such as lofty trees, steeples, and particularly the masts of ships and chimnles of houses, various expedients have been contrived, in order to divert, or at least break, its force. These efforts of human ingenuity were first published, or recommended to public notice, by Dr. : and, from their acknowledged utility, are now generally adopted:—we have already pointed out the most judicious form of constructing them, in pp. 47 and 48, of our 2d volume.

Another method of preventing the fatal effects of lightning, consists in the artificial attraction of electrical matter from the clouds, by means of a. Having, under that article, stated the manner in which this useful machine should be constructed, we shall now communicate a few directions for its proper management.

In order to adapt the electrical kite to the important purpose of affording security during a thunder-storm, especially when persons are exposed to its influence in an open field, it will first be requisite to fix