a glass or earthen vessel. The acid is to be poured upon the ground colour, in small quantities, and the mass well stirred up during the mixing, until the whole has become of a smooth semi-fluid consistence.

The proportionate quantity of the acid to that of the colour is not important, provided the materials be well mixed, as above described. This composition is called the "prepared Prussian Blue,” and may be used as soon as mixed, but is better if allowed to stand three or four days, and is not deteriorated by age.

If silk is to be dyed, it is first deprived of its gum by the usual means, and then immersed in a cold solution of alum in water, for three or four hours; it is then to be rinsed in clear water, which renders it in a proper state for the dye vat.

The dye is produced by the Prussian Blue, above prepared, diluted with cold water to the required strength. The silk having been introduced into the vat in hanks, suspended upon rods, it is to be there constantly turned about, that the colour may become equal throughout, and remain in the dye until the proper tint is obtained; after which it is to be washed as usual in a running stream, till the water ceases to be tinged by it. The silk is then dried, either in a shady place, in the open air, or in a drying room, the temperature of which does not exceed summer heat.

From the Prussian Blue, prepared as above, several variations of colour may be made, as greens and purples, by mixing the ordinary ingredients with the blue, or dipIping the articles to be dried at several times, into the different colours to produce the tint, which operation is not particularly explained, as the substance of the invention consists in" a mode of preparing Frussian Blue, so

as to dye silk, cotton, or any other article, either alone or mixed and combined with other dyeing materials."

[Inrolled December, 1823.]

TO ROBERT JOHN TYERS, of Piccadilly, Middlesex, Fruiterer, for a Machine or Apparatus, to be attached to Boots, Shoes, or other Coverings for the Feet, for the purpose of travelling, at pleasure.

[Sealed 22nd of April, 1823.]

THIS apparatus, which is called a VOLITO, is intended as a substitute for the ordinary skating shoe, used in sliding upon the ice. The volito, however, is intended to be employed for passing over any hard, smooth, level surface, by means of which the ordinary evolutions of skating may be performed upon a stone, brick, or wooden floor. Instead of the smooth bar of iron or steel placed under the sole of the shoe, as in the ordinary skate, it is proposed to substitute a series of small rollers, varying in diameter, the outer peripheries of which shall form a convex curve or segment of a circle.

Plate III, Fig. 6, is a side view of the volito, and Fig. 7, a representation of the under side of the same; a, is the sole, or wooden part, intended to be strapped to the foot; b bb, a series of rollers turning upon pivots in short staples, or ears, extending from the under side of the sole. These rollers are rounded on their edges and diminish in diameter from the centre one, in order to produce a curved bearing; c, is the stop at the heel part, but which may contain a roller, if the wearer should think it desirable.

The mode of attaching these rollers to the sole may be varied from that shewn in the figure, and when employed for travelling upon hard and smooth gravelled foot paths, the rollers should be made as broad as the frames will admit: sometimes it may be desirable to groove the rollers, in order to afford a broader bearing, which is considered to be desirable for learners in the art of skating, but not eligible in practising the evolutions of an expert skater. The patentee claims every mode of constructing these volitos, which he designates as the "Invention of applying a single line of wheels in place of the ordinary irons of skates."

[Inrolled October, 1823.]

TO WILLIAM CASLON, the Younger, late of Burton Crescent, in the County of Middlesex, but now of Rugeley, Staffordshire, Proprietor of Gas Works, for certain Improvements in the construction of Gasometers.

[Sealed 10th of May, 1823.]

THESE improvements in gasometers are designed to effect the following objects: 1st, to enable them to perform without the intervention of water; 2nd, to dispense with the tanks heretofore employed; and 3rd, to render their erection less expensive than gasometers of the old construction.

In Plate III. Fig. 4 and 5, are exhibited sections of a building, in which this improved gasometer is represented in the two positions which its parts would assume when the gas occupied the interior, as Fig. 4; and when the gas was nearly all expelled, as Fig. 6: the respective