only, when the strength of the rock, or earth, requires an increase of power.
Should the rock be elevated so considerably above the ground, as to endanger the men by its fall, when the separation takes place, the lever may be reversed; so that the labourers will stand upon the bar intended for the application of their hands, in common cases; and thus all danger will be effectually prevented.
Various other levers have been contrived; but, as they relate to particular branches of mechanics, we shall only take notice of Mr. Snart's sliding lever, which he quaintly calls an alexippos; and which was also laid before the patriotic Society above-mentioned.—As various accidents happen to horses that frequently fall, while they are in the shafts; and the present construction of carts, as well as other two-wheeled carriages, is especially unfavourable to the animal in such a situation, by preventing him from being speedily raised; Mr. Snart has contrived a lever for the express purpose of relieving the unfortunate quadruped. He farther states, that it may occasionally be of service in loading carts, where the common length of those vehicles is not in proportion to the articles to be carried.
The contrivance is ingenious, and, notwithstanding its pedantic name, deserves to be more generally known: but, as we are not disposed to enter into particulars, the inquisitive reader will resort to the 18th vol. of the Transactions of the Society for the Encouragement of Arts, &c. where this invention is fully described, and illustrated with an engraving.
LIENTERY, or Lienteria, is a species of diarrhœa, in which the food passes through the intestines, almost without having undergone any change: it is not attended with pain, but the patient is frequently affected with an intolerable hunger.
This disorder is occasioned by the relaxed state of the stomach, and is sometimes the consequence of dysentery, though it generally occurs during the earlier periods of life.
Considerable benefit may be derived by administering rhubarb, combined with magnesia; but, if the patient be an adult, it will be necessary to resort to stomachics and tonics, especially the Peruvian bark.
The lientery is seldom a very dangerous disease, unless the patient be of an advanced age; or the constitution be broken by excess, or acute diseases: in either case, the diet and treatment must be the same as in the Dysentery, to which we refer.
LIFE, in a peculiar sense, denotes the animated state of living creatures, or that space of time during which the soul is united to the body.
Longevity has always been highly estimated by man; hence the art of preserving life has become an important study, and ought to form part of the education of every individual.—There is, however, a period at which mankind cease to grow; and beyond which our existence continues for a limited time. Thus, if a person attain his full growth at the age of fifteen, he generally dies at that of sixty; provided that no accidents intervene, by which the vital principle be affected, and prematurely extinguished. According to the calcu-
