This instrument resembles in use the cyclographs of Mr. Nicholson and others, being intended for the purpose of describing, on a given chord, circular arcs, the centers of which are beyond the limits of the drawing-board, &c. and which therefore cannot be obtained by means of the compasses. The instruments above alluded to, however, are not capable of indicating the measurement in degrees of the arcs which they describe. This very desirable improvement is effected by the addition of a graduated quadrant, the divisions of which show on inspection the magnitude of the arc contained between the extremities of the chord line; that is, between the points of the block gg (Plate I, fig. 9), against which the limbs of the instrument work.

α α, α α are the two limbs, made either of wood or metal; to one of these is attached the brass quadrant b b, divided into 180 parts; attached to the other limb is an arc c d e, rather exceeding a quadrant; at c a fiducial edge is formed, and a point is marked at 90 degrees from the extremity of d; so that when the point c and zero on the graduated quadrant, coincide, the two limbs a a, a a are in a strait line; on the outer edge of the quadrant are two projections, with steel screws, on which work the nuts ff, the shoulders of which clamp the arc c d e to the quadrant b b in any position. It is evident that when the limbs are placed at an angle of 90 degrees, the point of the intersection, when made to traverse between the blocks g g, would describe a semicircle, and if placed in a strait line, the same point would only describe a strait line, or no portion of a circle; therefore the quadrant being formed into 180 divisions, the division marked by the point c will always indicate the quantity of the arc drawn by the instrument. The arc c d e is jointed near the fiducial edge, for the purpose of turning up out of the way of the blocks when the limbs approach towards a right angle. Fig. 10 is a section of the joint on a larger scale;

the axis is a tube for receiving the pen or pencil, with a flanch at the lower extremity. On this axis turn the two portions of the joint attached respectively to the limbs of the instrument, and the whole is surmounted by a collar, on the top of which the hollow axis is rivetted, and this rivet binds the whole together, by means of the flanch at the lower extremity of the axis. The blocks g g must not be so thick as to prevent the socket or tube which receives the drawing pen or pencil from passing over them.

PAPER

IN

MANUFACTURES.

MATTING MADE OF THE TYPHA LATIFOLIA.

The small or CERES MEDAL of the Society was this Session voted to Mr. WILLIAM SALISBURY, of Brompton, for MATTING, and other articles made of the TYPHA LATIFOLIA (greater Cat's tail). Specimens of the articles are placed in the Repository of the Society.

THE material of which matting, and the rush-bottoms (as they are called) of chairs, are usually made, is the scirpus lacustris, known in some parts of England by the name bullrush, and in Durham and Northumberland by that of poleciveIt grows naturally in deep slow streams, and is particularly abundant in the neighbourhood of Newport Pagnel, in Buckinghamshire.

The demand for this article, however, in the Newport

Pagnel manufactories is considerably greater than that district can supply, and in consequence large importations of the scirpus are made from Holland. Hence in time of war the article is often scarce, and at an exorbitant price.

Prior to the Winter of 1817, Mr. Salisbury, induced by a laudable desire of opening new sources of industry to the unemployed poor, attempted, in various ways, to apply the leaves of the typha latifolia (flag, or greater cat's-tail) to the same purposes as the scirpus. For this purpose he was allowed, by the overseers of the parish of St. George's, Hanover-square, tó employ some of their paupers in collecting about 2 tons of the typha from the marshy grounds about Little Chelsea and Clapham, and afterwards in manufacturing a part of it into mats, baskets, hassocks, chair-bottoms, &c.

Samples of these various articles were laid before the Society in December 1817, and it appeared that with equal skill in manipulation equally neat work might be produced from the scirpus and from the typha. It being, however, a matter of considerable importance to ascertain the relative durability of the two articles under similar circumstances of ordinary wear, the following experiment was made:-A piece of the best Dutch matting at 2s. 6d. a yard, and a similar one of Mr. Salisbury's manufacture were laid down side by side in the Society's premises on the 13th December 1817. Their relative situations were occasionally changed, in order to equalize, as nearly as possible, the wear to which they were exposed, and on 27th March, 1821, they were taken up and examined by the Committee of Manufactures. On minute inspection, they appeared to be about half worn out, and there was no very perceptible difference in the condition of each.

With regard to the relative expense of procuring and preparing the two articles for manufacture, the Society possess no

very certain data, as the use of the typha was at first set on foot chiefly in order to employ those parish poor who would otherwise have been idle. Two guineas were paid by Mr. S. for liberty to cut as much of the typha as he pleased from about ten acres of swampy land, near Hammersmith. The matting has been sold at from 9d. to 15d. per yard, and between 1,000 and 1,500 yards have been disposed of during the last three years.

The typha abounds in all marsh ditches and uncultivated swampy ground in every part of the kingdom, whereas the scirpus is found in quantity sufficient for manufacture only in certain districts; hence the former must be much more accessible and cheaper than even the scirpus of home growth; and the Society indulge the hope, that by giving this notice a place in their annual volume, the knowledge and the use of so abundant and cheap a material may be extended throughout the kingdom, and may form a means of domestic employment to the younger members of poor families.