LEWIS, one of the largest of the Hebrides, or Western Islands of Scotland, extending about eighty miles in length from north to south, and from thirteen to fourteen in breadth, consisting of a great number of isles and rocks, and parted by the sea into two divisions, called Lewis and Harris, the’ former lying to the westward of the latter. Lewis belongs to the county of Ross, is divided by several channels, distinguished by several names, and portioned out amongst different proprietors; but the Lewis, strictly so called, stretches out about thirty-six miles in length, from the northern point of Bowling Head to the southern extremity of Hussiness in Harris. The air is temperately cold, moist, and healthy; a great part of the low ground is flooded with lakes, and the rest is in some parts arable. Lewis is not so mountainous a region as Harris, but it is of as desert a character. Except along the margin of the sea, and in the immediate neighbourhood of Stornoway, the country is everywhere open, bare, brown, and uninteresting. The shores, particularly near the middle of the island, are deeply indented with arms of the sea, in which herrings and white fish are plentiful. A variety of streams, which issue often from small inland lakes, abound with trout and salmon. The grazing of cattle constitutes the chief means of support of the inhabitants. Lewis is divided into four parishes, viz. Barvas, Lochs, Stornoway, and Uig. There are a few scattered hamlets, but only one [7:13:264]town, Stornoway, which lies on the east side of the island, at the head of a bay or harbour, to which it gives its name. It is a place of considerable size, and there are in it schoolmasters and missionaries for the instruction of the inhabitants. It is a singular fact, that the latter are of unmixed Danish origin, which is the case in none of the other islands. The population amounts to about 12,000.

Lewis is the name of an instrument which is indented into a large stone, and has a ring for the purpose of making fast a rope, in order to move the stone, or to act as a stay. It is called in Italian ulivella, in French la louve, in German stein zange. The lewis consists of three wedges of iron, forming, when put together, a dovetail. The wedges are inserted into an equal and similar hollow dove-tail excavated in the stone. This hollow dove-tail is made exactly of the form and size of the lewis, and is a figure of six sides; a pair of vertical sides, which are opposite, equal, and parallel, and in form of truncated isosceles triangles; a pair of inclined sides, opposite equal rectangles, equally inclined to the axis of the hole, and not parallel. The top and base of the hole are rectangles parallel to each other, the base being longer than the top. The centre of the base and the centre of the top are in one vertical line. The form of the hole therefore is that of an inverted wedge with the point cut off; it is like a cavity fitted to contain the inverted keystone of an arch. When the iron dove-tail called the lewis is inserted into this hollow dove-tail made in the stone, the ring at the smaller and upper end of the iron dove-tail serves for making fast a rope, for the purpose of raising the stone. The constitution of the substance of timber enables the workman to fix a rope to it by merely inserting a screw or a spike into the log; stone will not admit of these, and is made fast by the contrivance of the lewis. The lewis of the most useful form, and that which is used in Britain, is represented at fig. A, Plate CCCXXL; a and b are two pieces of iron, in form of inverted wedges. These pieces are inserted into a quadrangular hole which is made in the stone. The two opposite and shortest sides of the hole are dove-tailed, or, in other words, under-cut, as represented at fig. B, which is a vertical section of the hole; t is the plan of the hole at top, o is the plan of the bottom of the hole. The hole, as represented in the figure, is five inches long at top, and six inches at bottom; the width is one inch; the depth seven inches. Sometimes the width is one and a half inch, and the depth four or five inches. The hole is made of such a size that the lewis fits exactly into it; a!, c', b , , are transverse geometrical views of the pieces «, c, b ; in the transverse views it is seen that the transverse sections of the parts of these pieces that enter the stone are of the same breadth from top to bottom. The piece c is represented with a perforation at top, for the purpose of taking out this piece more easily when the lewis is to be unshipped, but the lewis is usually made without this upper perforation. The pieces a, b, are first introduced into the hole, then is driven in c, which may either be a parallelepiped, or it may be a little thicker above, in form of a wedge; the ring m is then put on, and the bolt g h is passed through the holes of the ring and of the three pieces; the bolt enters at g, and forelocks at h. The tackle by which the stone is to be elevated is hooked on the ring m. This ring, in cases where a rope is to be passed through it, is bound round with cord, to prevent the rope from being chafed by the iron of the ring.

Piranesi has proposed and figured some other forms of this machine in his Antichitò di Roma, but they do not appear to be so convenient as the lewis of the common form above described: one of the forms of lewis given by Piranesi is represented at fig. F. The two pieces which constitute the iron dove-tail open and shut by a joint; n is a bolt, which is put into the round hole at p after the instrument is inserted into the stone; this transverse bolt serves to keep the legs of the instrument spread out, so as to retain the form of the dove-tail. The lewis of the most usual form, represented at fig. A, and a lewis of another form, fig. G, are figured and described in Perrault’s Vitruvius, lib. X. chap. 2, and in the Theatrum Machinaru m ^ tab. XXXV. p. 111. In the lewis, fig. G, the iron dove-tail L has a ring at top, r, for receiving a rope; L is put into the dove-tailed hole in the stone, and then the two parallelopipedal iron bolts e, u, are put in on each side of the iron dove-tail; e and u are of equal thickness throughout. The top of the hole must not be less than the bottom of the piece L, to the end that L may enter into the hole. The ring must not project beyond the lines which form the prolongation of the inclined sides of the wedge L; for if the ring projected, the pieces e, u, could not be put into the hole. The hole must be formed so that the machine may fit accurately into it.

The lewis is used for raising large stones of several tons weight, in the building of harbours, bridges, and other solid fabrics, which, from the forces by which they are assailed, or on account of the long period they are designed to endure, require to be constructed of great masses of stone. Leupold, in his Theatrum Machinarum, mentions, that in many churches in Holland the pavöment consists of large slabs of stone or marble, each of them the size of a grave, and covering a burying-place; these slabs are laid close to one another, and join accurately, so that no lever or crow can be introduced into the joint to raise them; in each of the slabs there is a hole cut in form of a hollow dove-tail, and into this hole a lewis is introduced when occasion requires that the tomb should be opened.

In the construction of harbours, the lewis fixed in a large stone frequently serves to make fast the ropes which stay the cranes. The lewis is commonly used in the docks at London for fixing mooring-rings in the stone: the ring is easily removed when requisite, by unshipping the bolt of the lewis; for this and other reasons it is found more convenient to employ the lewis for fixing rings, than to run the ring-bolt into the stone with melted lead.

The largest stones that have been wrought and moved by the industry of man, occur in the buildings of the ancient Egyptians; but it is not ascertained whether their architects employed the lewis.

Piranesi, in his Antichità di Roma, describes and figures lewis-holes existing in the upper surface of the large stones of the tomb of Caecilia Metella, at Capo di Bove, near Rome. The forcipes ferrei quorum dentes in saxa forata accommodantur, mentioned by Vitruvius (lib. x. cap. 2), denote a machine in the form of nippers, used to effect the raising of stones in the same way as the lewis; but the words seem to indicate a machine different in form from the lewis. Piranesi also observed in some ancient unfinished buildings, stones which appeared to have been raised by another method, namely, by knobs left on the front and side of the stone, to which knobs the ropes were attached. The knobs were taken off when the building was finished.

Vasari relates, in his account of Brunalesco, that the use of the lewis was revived in Italy by that architect, who was well skilled in mechanics, and who constructed the cupola of the cathedral church of Santa Maria del Fiore, at Florence, about the year 1430; the first great cupola that was built in Europe, and which Michel Angelo had in view when he designed the cupola of St Peter’s. The lewis called Brunalesco’s is represented at fig. C, Plate CCCXXI. Leo Baptista Alberti, a Florentine architect, who lived in 1440, in his treatise de Architectura, mentions the lewis by the Latin name of impleola. He describes the side wedges as having the figure of the letter [7:13:265]D and from that form the machine had its Italian name ulivella, that is to say, little olive. Philander of Chatillon, in his Commentary on Vitruvius, published at Rome in 1544, gives a figure of the lewis used at Rome in his time, which resembles that used in England, and represented at figure A. In the Archaeologiae (vol. x.) there is a description of holes observed in the keystones of the Abbey Church of Whitby, which was built about 1370, in the reign of Edward III. as is supposed. These holes appear to have been lewis-holes; they are of the form of an inverted Y, as represented at fig. D, where w is the plan of the top of the hole, and t t the plan of the bottom; the lewis that fitted into these holes would resemble that represented at fig. E. These keystones at Whitby weigh about one ton and a half.

Lewis, or Louis, the name of several kings of France. See the article France.