away and twelve brushes, to brush the cloth before it is pressed, may be fixed in their place.

4. A loom, with a fly-shuttle, and all its parts com. plete, worked by one person, placed in the middle.

Ingenious Application of Iceland Crystal to Telescopes.

Iceland crystal is known to possess the property of double refraction, and of giving two images. Of this M. Rochon has very ingeniously availed himself by placing a prism of this crystal in the inside of a telescope, which produces two images of the object observed, and these images are nearer or farther from each other according as the prism is more or less distant from the eye. If a ship be perceived at sea, which you have an interest in overtaking or avoiding, bring the two images in contact; if you are approaching the vessel the two images will gain upon each other; on the contrary, if the two vessels are removing to a greater distance from one another, the images will soon be perceived separate. It is easy to distinguish the rate or class of the vessel observed, and you will know nearly the dimensions of the mast. Bring in contact, end to end, the two images of the mainmast, and you will find how many masts length you are distant at the time from the vessel. By land you observe the images of a body of enemies, place the images so that the feet of one shall be on the head of the other; and if the average height of a soldier be computed at five feet six inches, the telescope will shew you how many times that length is contained in the distance which separates you from the enemy. This sketch is sufficient to explain the utility of an instrument which would be very interesting if it were only considered as an object of curiosity. The experiments with it were repeated at

St.

St. Cloud, 11 Prairial, (31st May,) in the presence of the First Consul, who ordered several telescopes of this kind to be made.

This discovery may also be of great use in astronomy. M. Rochon has already employed it to measure the diameters of Mars, Jupiter, and Saturn. He could not at first apply it to the sun and moon, the diameter of which is about 30', because the angle of refraction is only 20; but, by an ingenious method of cutting the crystals, Messrs. Rochon and Torelli di Narcy have doubled and trebled the angle of refraction; so that there is not now any planet whose diameter cannot be measured, if it be but sufficiently luminous; for it is obvious that the two images must be weaker than only one would be. But this inconvenience cannot be felt with regard to the sun and moon, which always diffuse too much light. One of these prisms will soon be adapted to the best telescope in the National Observatory.

Portsmouth Canal.

The estimates of the expense of the execution of the intended London and Portsmouth canal, and of its probable revenue when finished, being now perfected, it appears that the cost of the execution will be 721,000 l. and that the revenue will exceed 100,000 l. per annum. At a late general meeting at the Crown and Anchor, it was unanimously voted to open a subscription immediately for raising a capital of 800,000 l. in shares of 100 l. each, and to proceed to parliament for an act to carry the measure into effect. As this measure appears to us to be an important national object, we have subjoined an extract from Mr. Rennie's Report upon it. He concludes his report thus: "When, therefore, the extent of country through which this canal will pass is considered; the communications that will sooner or later take place, not

only

only with those navigations already made, but with others now in contemplation, and likely soon to be made; the abundance of ship-timber there is in the counties through which it will pass; the communications that will be opened with London, and with his Majesty's dock-yards at Portsmouth, Chatham, Woolwich, and Deptford, the city of Chichester, and the numerous towns and villages situated near to it; the various articles of traffic which must be carried between London and these places, and the local trade they will have with each other; the quan tities of timber, naval and military stores, which must be carried to and from his majesty's dock-yards, without being liable to the hazards of the sea, and uncertainty of the voyage, or risk of being taken by the enemy's cruizers: the quantities of goods which will be sent by the East India Company to their vessels when lying at Spithead; the immense quantities of chalk, from the inexhaustible chalk-pits bordering on the line, for manure; the quantity which will be wanted in London for lime, which is of an excellent quality, the quantity of coals, &c. &c. I say, taking the whole of these into consideration, I think this is one of the most important lines of inland navigation which have come under my observation."

List of Patents for Inventions, &c.

(Continued from Page 240.)

JAMES ROBERTS, of Abbotston - Farm, Southampton,

Yeoman, and GEORGE CATHERY, of New Alresford, in the same county, Gentleman; for a method of compleatly and effectually eradicating smut from wheat; and that wheat, when cleansed by their invention, will produce

flour

flour of as good quality and value as flour made from wheat of the best growth. Dated July 6, 1803.

JOSEPH MANTON, of Davies-street, Berkeley-square, in the parish of St. George, Hanover-square, Middlesex, Gun-maker; for a hammer, upon a new construction, for the locks of all kinds of fowling-pieces and small arms. Dated July 6, 1803.

JAMES STUARD, of London-street, in the parish of St. Dunstan Stepney, Middlesex; for a method to strengthen ships or floating vessels. Dated July 27, 1803.

JOHN NORTON, of Rolls-buildings, Fetter-lane, Fleetstreet, London, Mathematical Instrument-maker; for an improvement in the construction of a water-mill. Dated July 28, 1803.

THOMAS KENTISH, of Baker-street North, Portmansquare, Middlesex, Esquire; for a dewick, for the purpose of more expeditiously, with less labour, and at less expense than heretofore, loading and unloading ships and vessels, removing heavy bodies in any direction, and which is also applicable to other useful purposes. Dated July 29, 1803.

ARTHUR WOOLF, of Wood-street, Spa-fields, Middlesex, Engineer; for an improved apparatus for converting water or other liquid into vapour or steam, for the working steam-engines, for the heating of water or other liquid employed in brewing, distilling, dying, bleaching, tanning, and other processes connected with arts and manufactures; calculated also to make a stronger extract than can be obtained by the processes commonly in use from a given quantity of any vegetable or other substance from which extracts are or may be made without the danger of burning, scorching, or singeing, such vegetable or other substance, and applicable to various other pocesses. Dated July 29, 1803.

THE

REPERTORY

OF

ARTS, MANUFACTURES,

AND

AGRICULTURE.

NUMBER XVII. SECOND SERIES. Oct. 1, 1803.

Specification of the Patent granted to GEORGE BEAUMONT, of South Cross Land, near Huddesfield, in the County of York, and WALTER BEAUMONT, of the same Place, Manufacturers of Woollen Goods; for a Mixture to be used in the Preparation of Sheep or Lambs' Wool for various Parposes. Dated May 17, 1803.

To all to whom these presents shall come, &c. Now KNOW YE, that in compliance with the said proviso, we the said George and Walter Beaumont do hereby declare, that our said invention is described in manner. following; that is to say: Our mixture consists of oil united with or diffused in water, by means of an alkaline substance, namely, potash, or pearlash, or soda, or the volatile alkali called ammonia, but we give a decided preference to potash or pearlash. The proportions and manner of making the said mixture are the following: Dissolve the best potash alkali in the water, in the quantity of about twelve ounces of alkali, in each gallon of VOL. III.-SECOND SERIES. Tt water;