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wear its union with the sea, may be seen in immense numbers picking up the worms and small fishes deposited by the tide. It will also follow the course of the plough over the fields, and delights in the insects and worms which are thrown up by it. The cockchafer in its larva state, is a particular favourite with this bird. See Aves, Plate IX. fig. 1.

L. ridibundus, the black-cap, or pewit gull, breeds in the fens of Lincolnshire and Cambridgeshire, and, after the season of breeding is over, returns to the coasts. In some parts of Syria these birds are so familiar as to approach on being called, and to catch pieces of bread in the air as they are thrown up from the hands of the wo men. The old birds of this species are both rank and tough, but the young are eaten by many persons, and were formerly much admired for the table, taken so young as to be unable to fly. The particular islets in the feuny wastes of Lincolushire, which used to be preferred by these birds for breeding, were every year in winter cleared of weeds, rushes, and other impediments, in preparation for their retura in large flocks to breed in the spring, and when the young had attained the precise growth, several men were employed with long staves to hurry them into nets spread for their reception. This process constituted a favourite diversion, and the rich and fashionable assembled to be spectators of it from a considerable distance. The birds were sold at the rate of five shil lings per dozen, and in the details of royal and noble feasts, will be found to have constituted an article of high and almost indispensable importance.

L. catarractus, or the brown gull, weighs about three pounds. It is more frequent in the cold than in the warmer latitudes, and is perhaps the most daring and fierce of all the species. In the Faro islands, lambs are stated to be often torn to pieces by it, and carried to its nest. On the island of Foula, however, it is said to be highly valued on account of its enmity to the eagle, which it attacks, and follows with the most animated hostility, in this instance becoming the means of security to flocks. It frequently makes prey of the smaller gulls and of other birds, and is often observed to watch the movements of birds on the water, and as they are bearing off their prey in triumph and imagined security, to pounce upon them with amazing rapidity, obliging them to drop their victims, which in the

same instant are intercepted by this rapacious intruder. Even the albatross, when on the wing, though so much larger than this bird, is by no means a match for it in strength and courage, and finds its effectual resource only in alighting upon the water, which it does with all possible rapidity, when the skna immediately ceases to annoy it. During the season of incubation, the skua gull will attack every creature approaching its habitation, not excepting the human species, several of whom have been assailed by it in company, with an energy aud fury truly formidable. Its feathers are in high estimation, and thought by many equal to those of the goose. It is in many places killed merely for these.

L. tridactylus, or the tarrock, breeds in Scotland, and is found so far north as Spitzbergen. It is an attendant on the progress of whales and other large fishes, which drive the smaller inhabitants of the ocean into creeks and shallows, where the tarrocks suddenly dart on them, ensuring always an easy and full repast. They are very clamorous, swim and fly well, are often seen on detached pieces of ice, are used by the inhabitants of Greenland for food, their eggs being highly valued for the same purpose, while their skins are converted into materials for caps and garments. For the black-toed gull, see Aves, Plate IX. fig. 3.

LARYNX, the thick upper part of the aspera arteria, or wind-pipe. See ANA

TOMY.

LASERPITIUM, in botany, laserwort, a genus of the Pentandria Digynia class and order. Natural order of Umbellatæ or Umbelliferæ. Essential character: petals bent in, emarginate, spreading; fruit oblong, with eight membranaceous angles. There are fifteen species, natives of the South of Europe.

LASIOSTO MA, in botany, a genus o the Tetrandria Monogynia class and order. Natural order of Ap ocineæ, Jussieu. Essential character: calyx very short, five petalled, with two acute scales; corolla funnel form, four-cleft; capsule orbiculate, one-celled, two-seeded. There is only one species, viz. L. rouhamon; this is a shrub, seven or eight feet in height, with a greyish irregular bark, and a whitish wood; branches and branchlets opposite, covered with a russet down, spreading over the neighbouring trees. The branchlets are knobbed, and at each joint have a pair of leaves, ending in a point; they are of a pale green colour, on short petioles; flowers in small axillary

corymbs, on a small peduncle, which has two scales at the base; corolla white; capsule yellow; this shrub is called by the Caribs rouhahamon; it is in flower and fruit during the months of October and November; it is found on the banks of the river Sinemari, in Guiana, forty leagues from its mouth.

LAST, in general, signifies the burden or load of a ship.

It signifies also a certain measure of fish, corn, wool, leather, &c. A last of codfish, white herrings, meal, and ashes for soap, is twelve barrels; of corn or rapeseed, ten quarters; of gun-powder, twentyfour barrels of red-herrings, twenty cades; of hides, twelve dozen; of leather, twenty dickers; of pitch and tar, fourteen barrels of wool, twelve sacks; of stockfish, one thousand; of flax or feathers, 1700lb.

LATH, in building, a long, thin, and narrow slip of wood, nailed to the rafters of a roof or ceiling, in order to sustain the covering. These are distinguished into three kinds, according to the different kinds of wood of which they are made, viz, heart of oak, sap-lathis, and deal laths; of which the two last are used for ceilings and partitions, and the first for tiling only. Laths are also distinguished according to their length, into five feet, four feet, and three feet laths, though the statute allows but of two lengths, those of five, and those of three feet, each of which ought to be an inch and a half in breadth, and half an inch in thickness, but they are commonly less.

LATHS, of cleaving. The lath-cleavers having cut their timbers into lengths, they cleave each piece with wedges, into eight, twelve, or sixteen, according to the size of their timber, these pieces are called bolts; this is done by the felt-grain, which is that grain which is seen to run round in rings at the end of a piece of a tree. Thus they are cut out for the breadth of the laths, and this work is called felting. Afterwards they cleave the laths into their proper thicknesses with their chit, by the quarter-grain, which is that which runs in a straight line towards the pith. See GRAIN.

LATHE, in turning, is an engine used in turning wood, ivory, and other materials.

The lathe we are about to describe is made of iron in the best manner. See Plate LATHE. Fig. 1, is an elevation of the whole machine front wise; fig. 2, an elevation sideways; fig. 3, an elevation of the lathe only on a larger scale; in fig. 4, are two eleva

tions of an apparatus to be attached to the lathe for drilling holes; fig. 5, is an elevation of the rest; and fig. 6, a face elevation of one of the puppets.

The frame of the lathe is of wood, and consists of two ground cells, ub, two uprights, dd, morticed into them, and cross pieces, ef, at top connecting them together; upon the uppermost of these pieces the bench sustaining the lathe is fixed; g is another bench, supported by iron brackets, to receive a vice or other tools at the option of the workmen; between the two up. rights, dd, the axis of the great foot wheel turns, it is pointed at the ends and turns in small conical holes in pieces of hard steel let into the uprights, d d, one of these holes is in the end of a screw, by turning which, the axis can be tightened up so as to turn very freely without any shake; the axis is made of wrought iron, and the points at the end are of hard steel welded together, it is bent in the middle to form a crank; and h is the connecting rod by which it is moved from a treadle, i; the treadle is a piece of board, i, seen endways, in fig. 2, screwed 'to an axle, k, at one end, on which it turns, and at the other end is broader to receive the workman's foot; in the middle a staple is fixed, and the connecting rod, h, hooked to it; A is the great wheel of cast iron, and of considerable weight in the rim, wedged fast on the axis, and turns round with it; it is by the momentum of this wheel that it continues to turn, while the crank and treadle are rising, and consequently when the workman exerts no power upon them. When the crank has passed the vertical position, and begins to descend, he presses his foot upon the treadle, to give the wheel a sufficient impetus, to continue its motion until it arrives at the same position again.

We now come to describe the upper part of the machine, or lathe, the wheel and treadle being only the first mover, it is shewn on a larger scale in fig. 3, and it is to this figure we shall refer in describing it; BB is a strong triangular iron bar, firmly supported by its ends, on two short pillars screwed at their lower ends to the bench; this bar is perfectly straight and the sides flat; DE are two iron standards, called puppets, fitted upon the triangular bar, D, and fixed at any place by screws, they are both alike, and one of them is shewn endways in fig. 6, it has an opening made in it at the bottom, the inside of which is filed extremely true to fit upon the upper angle of

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the bar B B, through each of the branches, formed by the opening in the bottom mortices, are cut as is well seen in fig. 3; these receive the end of a short piece of iron, m, having a screw tapped into it; it is by screwing this screw tight up against the underside of the bar, that the puppet is fas tened upon it; a small piece of iron plate is put between the end of the screw and the underside of the bar, to defend it from bruises by the latter; the upper end of the puppets are perforated with cylindrical holes, to receive truly turned pins, n n, and which are fixed at any place by screws, oo, these holes must be exactly in a line with each other, when the puppets are set at any place upon the bar, and it is to accomplish this, that too much care cannot be taken in forming the bar perfectly straight and true in the first instance, and of sufficient strength to preserve its figure. F is another puppet, fixed on the bar, in the same manner as D and E; it has a conical hole through its upper end, whose centre is exactly in the same line with the holes through the other two puppets D and E, this conical hole is the socket for the mandrill, G, to turn in, being conical at that part, and fitting the socket with the greatest accuracy; the other end is pointed, and turns in a hole made in the pin, n, of the puppet, D, and which besides the screw, o, has another at its end tapped into a cock, screwed to the puppet, to keep it up to its work; the mandrill has a pulley Exed on it, with three grooves of different sizes, to receive a band of catgut which goes over it, and round the great iron wheel, A A; it is by this that the mandrill is turned. I is the rest, composed of three principal pieces, shown separate in fig. 5, one of these pieces, r, is filed to an angle withinside, and furnished with a screw similar to the puppets, whereby it can be fastened to the bar; on each side of this, pieces of iron, 8 s, are laid on the bar, and are fastened together by two short bars, tt, to which they are both screwed, the main piece, r, being cut away to make room for them. L is the bottom part of the rest, supported on the two pieces, ss, it has a dove-tailed groove along the underside, a button, with a head like a screw, is fastened to the top of the main piece, r, and is received into the groove; when the screw of the piece, r, is turned, it draws the button down towards the bar, and as its head takes its bearing on the inside of the groove, it must hold the piece L fast down upon the pieces, ss; when the

screw is loosened the whole rest can be moved along the bar B, the piece L can be slid backwards and forwards upon the pieces, s s, or it can be turned round upon the button of the piece, r, as a centre, at the convenience of the workmen; and all these motions are firmly clamped by the screw beneath the bar. The piece L has at one end a short iron tube fixed to it, in this an iron pin is fitted, to hold at its upper end the cross bar, V, on which the tool is laid, a screw is fixed in the tube, and a nut upon it presses a piece of iron, w, upon the ends of two short pins going through the tube, the other ends take against the large iron pin of the rest, V; when the nut is unscrewed the rest can be set higher or lower, or turned round obliquely, and fixed by turning the nut; the bar, v, of the rest, is fixed on by a screw, so that it can be easily changed for another when worn, or for different work there should be two or three of different sizes with the lathe. The mandrill, G, of the lathe should be of iron, and at the part where it turns in the collar, F, it should have a piece of good steel welded round it, and turned very true in a lathe, and also the point at the end should be of steel; a small hole is drilled down from the top of the puppet, F, into the collar to supply it occasionally with oil. The end of the mandrill, beyond the collar, is formed into a male screw, whereon to fix the work to be turned. The manner of holding the work varies in almost every instance, and is explained under the article TURNING; in general, it is held in pieces of wood called cheeks, screwed to the mandrill, they are turned hollow like a dish, and the work is driven into the cavity, as shown in fig. 1.

LATHRÆA, in botany, a genus of the Didynamia Angiospermia class and order. Natural order of Personatæ. Pediculares, Jussieu. Essential character; calyx fourcleft; gland depressed at the base of the suture of the germ; capsule one-celled. There are four species, of which L. squamaria, great tooth-wort, has a headed root, branched and surrounded with white succulent scales; it is parasitical, and generally attached to the roots of elms, hasels, or some other trees, in a shady situation; or, it has usually a naked stem; flowers in a spike from one side of the stem in a double row; calyx hairy; segments equal; corolla pale purple, or flesh-coloured, except the lower lips, which is white. Native of most parts of Europe.

LATHYRUS, in botany, a genus of the

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