Proposition III. " To survey the in dined parallelogram ABCD, fig. 3." It, is to be observed that, in all inclined fi gures, the altitude is ascertained by a per pendicular from the base, as at C, to the parallel of that base, as at E, on the line Proposition XI. "To carry a line of sight or a level, in the direction pf AB, over the rising ground C." Ascertain where the line of sight strikes the hill at e; carry the instrument to that point, and, in the exact direction of the former sight, take a second sight from e to a, or to any convenient spot, where a pole and target should be fixed. See LEVELS. As this survey for a canal is to be taken by means of a spirit level, the exact altitude of each sight must be taken, by noting the height of the target from the plain, AB, at every sight, or by following up a regular succession of levels, each of which will be the height of the instru ment above the last. Thus the hill will be ascended : the descent on the other side is effected by the inversion of the foregoing mode ; always taking the de scending levels of the target for canals; but for roads, or for laying down a meridional line, when once the summit is gained, a long sight may be taken to a distant object: this subject is pleasingly exemplified in a new work published by Longman and Co. entitled " Mathematics simplified, and practically illustrated," in which a great variety of instructive and useful matter will be found, together with a description of a new instrument, on a very simple con struction, said to be equal to every branch of surveying.
SUS, the hog, in natural history, a ge nifs of Mammalia, of the order of Bellme. Generic character : four front teeth in the upper jaw, converging; six in the lower, projecting ; two tusks in the up per jaw, short ; two in the lower, standing out ; snout truncate, prominent, and moveable : feet cloven. These animals are allied by their teeth to the carnivo rous quadrupeds, and by their cloven feet te the ruminating ones. They feed almost indifferently upon animal and vegetable substances, devouring with avidity what is most nauseous and 'disgusting. They use their snout for digging up the ground,in quest of roots, are fond of rolling and wal lowing in mud, and are distinguished by extreme fecundity. There are six species, of which the following are the most im portant : S. scrofa, the common hog. All the varieties of this animal originate in the wild boar, which is found in most of the temperate regions of Europe and Asia. It is smaller than the domesticated animal, and uniformly of a dark grey colour, ap proaching to black. It is armed with for midable tusks, sometimes ten inches, or even more, in length ; those in the under jaw curving inwards, and capable, from their size, strength, and sharpness, of in flicting the must dreadful wounds. Before these animals attain their third year they are gregarious, and, when danger is at hand, particularly, they muster in nume rious parties, and with great promptitude, at the signal of alarm. Uniting thus, they present so formidable an array, as speedi ly to disperse the enemy, few creatures, or none, daring to commence an attack against such a combination of strength and. valour as they exhibit. When the wild boar is complete in growth, he de pends upon his solitary exertions for his protection, is seldom seen in society, ranging the forests alone ; rarely com mencing an attack, as his food consists al most solely of roots and vegetables, but repelling one with all the fiercenes of courage, and all the resentment of reta liation.
These animals are often hunted by dogs, particularly of the mastiff breed. After many pauses in their progress, in which they turn round, and defy their enemies to the attack, which, however, is gene ra* declined, they at length refuse to p ed, and halt for the grand and final conflict ; in which, though eventually overpowered by the number of dogs, and the spears of the hunters, they de fend themselves with the most astonish ing intrepidity, perseverance, and energy; and, regarding their case as absolutely desperate, determine, at least, not to die unrevenged. See Mammalia, Plate XXI.
fig. 11 The common hog has smaller tusks and larger ears than the wild boar, and is generally of a dull, or dirty, yellowish white. It is clumsy in its shape, filthy in its manners, and gross and ravenous in its food, devouring almost every variety of rejected animal or vegetable substance, and distinguished by the quantity nearly as much as by the rankness of its food. The offal of the garden, and barn, furnishes it with • an exquisite banquet. It was rejected as unclean both by the founders of the Jewish and Ma hometan religion, as unfit for human sus tenance, for which, it is, nevertheless, most admirably adapted, and of incalcula ble.alue. The sailors of the British navy are in a great degree supported by the flesh of that animal, which Moses and Mahomet decided to be unfit for the food of man ; and in most countries of Europe, it:is an important and indispensable arti cle of the food of the inhabitants. The hog is possessed of an acute smell, and is highly agitated during the violent blow ing of certain winds, uttering the most dreadful screams, and exhibiting the highest restlessness, apprehension, and turbulence. It is fattened to an extraor dinary size, and has been known to attain the almost incredible weight of 1215 pounds. It produces two litters in the year, and in each from ten to twenty young ones. The male must be kept at a distance from these, as it will other wise destroy and devour them, and the female herself has often acted this unnatu ral part, and is particularly apt to do it, if observed attentively, during the crisis of parturition. The hog was unknown in America when that quarter or the world was discovered by the Spaniards, hut now abounds in every part of it. The Chinese breed is most valued in England, :There is an accidental variety of the do mestic hog with undivided hoofs.
S. Ethiopicus, or the Ethiopian hog, is very similar to the last. It is fierce and formidable in the highest degree, and burrows in the ground, in deep recesses, which it _prepares with both its hoofs and nose. It is particularly distinguish ed by a large lobe, or wattle, beneath each eye.
S. baby-roussa is remarkable for the form and situation of the upper tusks, which are placed externally, and turn upwards in a curve towards the forehead. It abounds in the Indian islands, lives solely on vegetables, and rests itself, in sleep, by hooking its upper tusks round the branch of a tree. It can swim with rapidity, and is valued for food.
S. sajassu, or the Mexican hog, or pe tali, is the only animal of the genus na tive of America, where it is gregarious, fierce and dangerous, and is occasionally seen in 'herds of several hundreds. It feeds on fruits and roots, and also on serpents, lizards, and toads ; and will at tack and devour the rattlesnake, we are told, without the slightest injury. It is less than the common hog, has bristles nearly resembling the prickles of an hedge-hog, and is also distinguished by an orifice on its back, from which Per petually issues a most fetid watery hu mour. The pecari will skin snakes by means of its teeth and feet, belbre it devours them, with great dexterity. The common hog is reported, on good au thority, to attack and eat the rattle-snake with the same impunity as the pecari. For the baby-roussa, see Mammalia, Plate XX. fig. 2.