ground that Sir Isaac Newton had not taken into consideration the centrifugal force or friction arising from the pressure of the concentric rings or filaments round the cylinder, the fluid being supposed in a state of permanence, and the friction of the rings equal throughout.

Pitot (1728), in his experiments on the water-works at Marly and Versailles, was the first to demonstrate with equal velocities, and in the ratio of the volume of water, the friction of water in pipes was in the inverse ratio of their diameters; and Couplet (1733), Marriotte, and Deparcieux, estimated the difference between the real and calculated expenditures of glass tubes and pipes.

Chezy (in 1771 and 1786) was the first engineer who endeavoured to establish the relation subsisting between the inclination of an aqueduct and the transverse section of the volume of water it ought to carry,- -on the supposition that the accelerating force, due to the inclination of the bed of the conduit, is counterbalanced by the resistances of the channel in the ratio of the surface, and increasing in proportion to the square of the velocity. What Chezy had remarked was concluded by Bossut, who cleared the investigation of most of its difficulties, and demonstrated it to be in accordance with theory. He found that small orifices discharged less water in proportion than great ones on account of friction; that the vena contracta, and consequent expenditure, diminished with the height of the reservoir; he pointed out the law by which the discharge diminishes according to the inclination and number of bends in a pipe, and the influence of friction in retarding the velocity of waters moving in canals and pipes, in which he made the square of the velocity to be in the inverse ratio of the length of the pipe; he determined the co-efficients by experiment, and thus obtained a formula expressive of the conditions of the uniform motion of water in open canals. The greater part of these hypotheses may be said to have been removed by the more extensive researches of Dubuat. His great hydraulic work, published in 1779 and 1786, contains a series of the most valuable observations, whose results accord very nearly with the new formula of the motion of water in pipes and open conduits; and his experiments, with pipes inclined in various angles from the 40,000th part of a right angle to 90 degrees, and in channels which varied from a line and a half in diameter to areas of seven or eight square toises, seem to comprehend every case of inclination; so that by collecting a prodigious number of facts, both with compressible and incompressible fluids, he obtained a general expression for all cases relative to the friction and cohesion of fluids: but a logarithmic function which he introduces in it, by a sort of approximation, gives it a character of uncer

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tainty, which restrains its use, and shows the necessity of fresh researches. Ventruri, in 1798, Sur la Communication latérale du Mouvements dans les Fluides," repeated acd added many new facts to the experiments of Bossut, on the expenditure of differently shaped orifices and tubes, but particularly on the lateral communication of motion by the cohesion of fluids. Coulomb first approximated to the solution of the question, by a very ingenious apparatus, consisting of discs of different sizes, fixed by their centres to the lower extremity of a brass wire, and made to oscillate in fluids by the force of torsion only; he concluded that the resistance was a function, composed of two terms, one proportional to the first, the other to the second powers of the resistance: again, that it was not sensibly increased by increasing the height of the fluid, but simply by the cohesion of the particles of the fluid which presented greater or less resistance, in proportion to the viscidity of the fluid, oil being to water in the ratio of 17.5 to 1. But whatever might be the conclusions of Coulomb, it is obvious that both the size and constructian of his apparatus were ill calculated to produce results whereon to found a satisfactory theory; and accordingly both Messrs. Prony and Girard, in expressing their formulæ of resistanc, have not admitted that of Coulomb, but have adopted the mean of the best of experiments made by other authors: but as these formulæ give only the mean velocity, which is much greater than the velocity (of the fluid contiguous to the pipe) which ought alone to enter into the expression of the retarding force, it follows that the co-efficients deduced from the mean of all the experiments adopted by these gentlemen, have a value greatly inferior to the motion of the fluid contiguous to the side of the pipe or conduit. To ascertain correctly the value of this kind of resistance, M. Girard (vide les Mémoires des Scavans etrangers for 1815), undertook a prodigious number of experiments on tubes of different diameters and length, from which he deduced that the retardation is as the velocity simple. The effects of temperature are very remarkable: if the velocity be expressed by 10, when the temperature is 0° centrigrade thermometer, the velocity will be 42°, or increased four times when the temperature is 85°: these values must be deemed approximations only.

The contributions of British philosophers towards the improvement of this science have been, unfortunately, scanty; for, with the exception of Sir Isaac Newton (who led the way), Dr. Jurin, Dr. Matthew Young, Dr. Desaguliers, Dr. Vince, Mr. Smeaton, Mr. Banks, and the late Dr. Thomas Young, (see the paper of the latter gentleman in the Philosophical Transactions, and his commentaries on Eytelwein's experiments), we can scarcely find any experiments on the subject; whatever has been effected by our

engineers or scientific men, has either been withheld from the public, or consigned to obscurity; and though we have tracts of marshes and fen land, consisting of many thousand acres, the dissertations on the mode of draining and carrying off their superfluous waters are confined to local pamphlets and reports, of comparatively minor interest to the science of hydraulics.

From the foregoing short but imperfect history, it is obvious that much has been done towards perfeeting this science. It is however certain, that much yet remains to be accomplished; and although we are deeply indebted to both the French and English philosophers for their extensive investigations on the laws of capillary attraction, the descents of globes in fluids, and the adhesion of fluids to metal discs, the phenomena of fluidity, and the laws which govern the motion and equilibrium of their particles, must yet remain a problem purely geometrical; and as we possess no tangible means of approximating to the solution of the problem, but through the intervention of a solid, we must content ourselves, in like manner, with the imperfect formulæ deduced from experiments made on a small scale on the friction and adhesion of water in pipes and conduits, until we can ascertaiu more correctly the causes of the retardations of rivers as they accur in nature.

LITERARY AND SCIENTIFIC MISCELLANY.

Druidical Remains. A few days ago Mr. Cole of Scarborough discovered in the vicinity of the village of Cloughton, a druidical circle, near to the one pointed out by John Wharton, Esq., a few weeks since. It is about twelve yards in diameter, having the altar stone remaining, and is in a direction bearing N.N.E. from the Wharton circle. Its site is in a vale, called Hulley's Hack, and near it flows a clear spring of water. It is bounded by the plantation nominated Lind Ridge or Rigs, on the opposite elevation.

Highland Scenery. An extensive pictorial and trigonometrical survey of the Highlands and islands of Scotland has been commenced this year by Lieutenant Colonel Murray, who has already traversed a large portion of the West Highlands.

APPENDIX

To the Report of the Select Committee of the House of Commons, on Patents.

Papers delivered in by John Farey, Esq.

[British Law of Patents for Inventions.]

(Continued from page 108.)

THE specification, after describing the stove, thus claimed as the invention, that the fuel necessary for supplying the fire, shall be introduced at the lower part of the grate, in a perpendicular or oblique direction; as to the manner of performing it, that is set forth in the description and drawings.

It was proved that grates for cooking had been made before, with moveable bottoms, to be raised up by racks and pinions, and with doors to shut against the front bars, so as to conceal the fire; but those were schemes to contract or enlarge the depth of the fire-grate, according to the size of the meat to be roasted; and the doors were to shut in the heat for cooking, when the fire was not required for roasting; it was never thought, or intended, to use the doors to form chambers, which would contain a supply of fuel, that could be introduced into the fire places from below upwards.

Lord Ellenborough was of opinion, that the principle on which those grates were constructed, was identical with the concluding terms of the specification; that the patentee, by thus summing up the extent of his invention, had confined himself to that principle, which was not new; and therefore the patent could not be supported, although the application of the principle, as described in the specification, might be new. The patent was ordered to be cancelled, and repealed

Bovill against Moore and others. An action brought by direction of the Lord Chancellor, for Infringement of Brown's Patent of 1811 (assigned to Bovill), for "a machine for the manufacture of Bobbin Lace or Twist Net, resembling Buckinghamshire Lace, as made by hand, with Bobbin on Pillows." Tried in the Common Pleas, 1st March 1816, before Lord Chief Justice Gibbs. Verdict against the Patentee.

The machine was for making several narrow breadths of Lace, side by side. The fabric of real Buckinghamshire lace requires two systems of threads, like the warp and weft in cloth; the longitudinal threads extend lengthways of the piece, and intertwist

with diagonal threads, which latter traverse the breadth obliquely, from edge to edge, and then return with an opposite obliquity, whereby the different diagonal threads, which are so traversing in opposite directions, cross each other, and their intersections form the tops and bottoms of the hexagonal meshes of the lace; the sides of those meshes being formed by the inter-twisting of the diagonal threads, with the longitudinal threads.

All the varieties of lace that could be made by machines founded upon Morris's patent of 1764, were only imitations, by knittingwork, without any diagonal threads or twisting, which are essential conditions to make lace, which will retain the figure of its meshes after washing.

The first successful machine for making the real twist lace, was Heathcoat's patent of 1809; he warped the longitudinal threads on a roller, and wound up the lace on another roller, as fast as it was made, as the warp is wound in a loom for weaving cloth, only the warp stood in a vertical plane; the weft was supplied by a very different principle from common weaving; for in lieu of a shuttle, each of the diagonal threads was wound upon a separate thin flat bobbin, shaped like the sheave of a pulley, and about the size of a shilling; they were all placed in a row, side by side, in proper carriages, without touching each other, thus forming as many distinct shuttles as there were threads in the warp. In the operation, the row of bobbins was put through the spaces between the upright warp threads, penetrating through the plane of the wap from front to back, and after making a small lateral movement, the bobbins were returned again through that plane, or between the vertical warp threads, from back to front; each bobbin, in so doing, passed and returned at the opposite sides of its corresponding warp thread; and by repeating that manipulation, each bobbin thread became twisted around each warp thread, so as to make the sides of a row of hexagonal meshes. The twisting being done, the bobbins were arranged in a new order in their row, by passing each one round to the other side of its neighbour, by moving sufficiently sideways. This evolution effected the mutual crossings of the diagonal threads, each one crossing over the adjoining one, so as to make the tops and bottoms of the row of hexagonal meshes. A correct shape was then given to that row of meshes, by inserting a row of pins into them, to keep them open to the proper size, whilst a succeeding row of meshes was formed, as before; by first twisting the longitudinal threads with the adjacent diagonal threads, then crossing the adjacent diagonal threads over each other, and then inserting another row of pins, to give shape to the meshes so formed.

Heathcoat's machine was applied to make wide pieces of lace net, but it was also capable of making a row of distinct breadths,