the improved mode or method of extracting or obtaining milk from cows and other animals, by distending or opening the mouth or orifice of the teat, by keeping the sphincter muscle distended or forced back during the time the milk is running out of the udder; and also the improved apparatus above described for this purpose, viz. the hollow probes, tubes, or pipes, which effect the keeping open of the orifice of the teat, and form a free passage for the milk to flow out of the udder; the admission of air into the udder being at the same time prevented.—[Inrolled in the Rolls Chapel Office, September, 1836.]

Specification drawn by Messrs. Newton and Berry.

To SAMUEL GARNER, of Lombard-street, in the city of London, gentleman, for an improvement in the art of multiplying certain drawings and engravings or impressions, being a communication from a foreigner residing abroad.-[Sealed 15th November, 1834.] ́

THE subject of this invention is the formation, preparation, and treatment of plates of zinc, in order to suit them more perfectly than has been heretofore done to the purposes for which slabs of stone are used in lithographic printing, but in the present state of that art, which may now be called zincography, preference is given to metal of the purest quality.

When it is deemed desirable to give to the metal greater density than it possesses in its simply cast form, the improved plates are to be subjected to the pressure of a pair of metal rollers, passing them through at a temperature at which the metal is malleable, alternately in the direction of

the length and breadth of the two superficial dimensions of the plates, in order to prevent the metal from taking a fibrous texture, as it does in some degree when repeatedly rolled in only one direction. The action of the rollers thus managed produces a more uniform condensation of the metal than can be effected by planishing with the hammer. The cast plates, whether subsequently laminated or not, are to be brought to an accurate uniformity of thickness, by being planed on one or both of their faces by a planing engine, such as is now commonly used for planing the surfaces of other metals, by which means an accurately flat working face is obtained, which conduces essentially to the more certain and uniform action of the press in the operation of working off the impressions.

To render the surface of the metal better adapted to receive the subject to be delineated thereon, it is advisable to impart to it a certain roughness, termed technically a grain : this is effected by rubbing the surface with some cutting substance in a pulverulent form, such as silicious sands, emery, stone, or marble-dust, pounded pumice, rotten-stone, charcoal-powder, or other such materials, having the requisite property of abraiding the metal. Some such substances may be used for the purpose in masses or lumps, as pumice-stone, charcoal, &c.

These materials may be employed with water, or other non-solvent liquid, being rubbed upon the metal surface in all directions, until an uniformity of grain is produced. Two plates may be used to grind each other, or a muller may be employed, or leather, or other soft substance, may be the instrument for the application of the cutting powder to the metal, and the fineness or coarseness of the grain desired to be produced, will of course determine the sort of material proper to be used; but in all cases it must be guarded against applying matters of such coarseness as

VOL. IX.

will cut deeply into the plate, it being the object to produce a slight roughness of surface in a regular grain.

Sometimes, perhaps, it may be useful to give a different grain to different parts of the same plate, with a view to accommodate the artist in assisting to impart a variety of character to his work; this can be done by using the grinding materials of different qualities in different parts of the plate, conducting the operation by hand, with such partial applications as may be desired.

The grinding being completed, the material must be washed off, and the plate cleansed from impurities, to prepare it for the reception of the writing or design which should be done with a solution of alkali, either potash or soda, caustic or sub-carbonated.

The lines or traces to be printed from the zinc plate, are to be made thereon by similar materials and preparations to those used for the like purposes in the art of lithography; and this being done either by hand or by transfer, the plates are to be fixed and prepared for the subsequent operations, and brushed over the surface with an acid liquor, such as the one prepared in the following manner :Boil in a pint of water about one ounce and a quarter of bruised gall-nuts until the fluid is reduced one-third; pass the decoction when cool through a sieve or fine linen strainer, to separate the clear liquor: to which add about two fluid drachms of nitric acid, and three or four drops of muriatic acid. This may be varied as to the proportions of the acids, according to the nature or strength of the work to be produced; a weaker solution of acid will best suit the more delicate work.

The acid liquor may be brushed over the work with the tool ordinarily employed for such purposes, and it may be left to act thereon, and on the metal for a longer or shorter time, according to the strength of the lines or work

to be fixed; a few minutes will commonly suffice, but no injury appears to result from a longer time. The plate should then be washed with clean water to free it from the acid, and then the work may be covered with gum water, as is done on stone.

Other acidulated liquors than the one above described may be made use of for fixing the work upon the plate; such as any diluted acid, the action of which on the metal will be moderate-or solutions of many of the super-acid salts; for example, muriate, or nitro-muriate of tin; but for general purposes, the Patentee prefers the preparation above described, and claims to use, where convenient, for special purposes, any other form cr preparation of acidulated liquor.

The zinc plates prepared and treated in the way herein described, answer for the reception and re-delivery, by impression, of all the different kinds of work now usually executed by means of stone, in the art of lithography, and equalling the stone in all the properties dependant on surface; they have also the great superiority of being able to bear the action of other kinds of presses, than those which have been especially adapted to the working off impressions from stone. The copper-plate roller press, the ordinary type press, and others giving adequate pressure over the whole surface of the plate, may be employed with due effect in taking impressions from the zinc plates.

The Patentee concludes by stating his claim of invention in the following peculiarly constructed sentence :-"In the processes herein described, for the formation, preparation, and treatment of plates of zinc, to fit them more effectually than they have heretofore been found, for the purpose of multiplying copies by printing of lines, traces, or markings, made by certain materials upon their surfaces consecutively used as now indicated, either to the whole ex

tent or partially, by the omission of some one or more of the processes; for instance, condensation of the metal between rollers, or modified, as by change of material, to produce certain effects; for instance, graining and fixing the lines or design upon the metal, consists the invention for which I have obtained the grant of the herein partially recited Letters Patent."-[Inrolled in the Inrolment Office, May, 1836.]

TO THOMAS RIDGWAY BRIDSON, of Great Bolton, in the county of Lancaster, bleacher, for his invention of a certain improvement or improvements to facilitate and expedite the bleaching of linen and other vegetable fibres.[Sealed 7th April, 1836.]

THESE improvements in bleaching linen and other fibrous substances, have for their object the expedition of the process, by means of performing all the operations between. the first and last wheeling in one vessel or kier, thereby avoiding the loss of time attendant upon the usual process in conveying the goods between each operation from one vessel to another.

Plate VI., fig. 11, represents the section of a kier suited for the above purpose; fig. 12, is a plan or horizontal view of the same: a, a, is a kier, composed of any material that will not be affected by the action of the chemical agents employed in the process; b, b, is a false bottom, perforated with a number of holes, for the purpose of allowing the drainage of the different solutions to be admitted to the materials under operation; c, is a pipe proceeding from a boiler or other source, for the purpose of conveying steam, when required, to the chamber d; e, f, g, h, i, are pipes, provided with cocks, for the admission of alkaline,