diameter, and three feet long. They are to be so inclined to the axis that one-sixth of the whole length of the bar shall be brought into action in one revolution of the cylinder. In order to form these cutting bars with perfect accuracy, it is proposed that six bars of steel shall be wound round a cylinder, and there operated upon by turning or grinding until they have acquired a truly concentric or circular periphery'; they are then to be removed and hardened. The three bars not intended to be employed may be reserved to supply the place of any one injured by accident.

The patentee states that his "invention consists only in the improved make, form, or structure, of the said cutting bars, and does not embrace or require any alteration in the ledger-blades, or in any other parts of the various machines in use for shearing or cropping. The revolving steel cutters of the improved form may be used as substitutes for the rotatory cutters employed in machines in common use."

Inrolled, October, 1821.

To ROBERT FORD, of Abingdon-row, Goswell-streetroad, Middlesex, for his Discovery of a chemical Liquid, or Solution of Annotta.

ANNOTTA, or Annatto, (a term derived, we believe, from a Spanish word implying to mark) is obtained from the red pulp which covers the seeds of the Bixa orellana, Roucon or Annatto-tree, a native of South America. Annatto is found in commerce under various forms and names; such as flag annatto, because brought to this country enveloped in flags; Spanish annatto, which is in

Ford's, for a Solution of Annotta.

71

cylindrical rolls; and occasionally also in the shape of an egg, hence called egg annatto. But the annatto most known to the British public, generally, is a composition of the imported annatto, turmeric, an alkaline salt, and some common colouring earth, such as Venetian red or Spanish brown. It is made up in cakes of about four ounces each, and is used chiefly by the farmers in the dairy counties for colouring their cheese. The quantity sold annually in England is incredibly great : fortunes of no small amount have been made by the manufacture and sale of cake annatto. The imported annatto is used as a dyeing material for giving orange, or colours bordering on the orange, to various cloths.

The patentee proposes, in order to make twenty gallons of the chemical liquid or solution of annotta, to take about fifty-six pounds of annotta, and reduce it with warm water; then to pass it through a fine sieve, and suffer it to stand at least seven days. To this he then adds the leys of sub-carbonated potash in a "sufficient quantity to produce the colour required;" but states, that other suitable articles may be employed for the same purpose, the quantity and strength being regulated according to the colour intended to be produced, and also according to the quality of the annotta. To the above ingredients are now to be added about six pints of the aqua lixivum caustic, and 192 ounces of alcohol; the whole of which are to be mixed together, keeping it in a closed vessel; and, in conclusion, states, "I farther declare, that as my invention consists in producing a liquid or solution of annatto, (an article I believe to be entirely new,) I shall consider any similar production whether from different articles or variations of quantity of the aforesaid articles, or by what means they are produced, as an infringement on my patent right, as every chemist

must be aware that there are ingredients other than those mentioned above, which may with effect be made to supply their or either of their places."

This is not one of the least extraordinary patents which are from time to time enrolled. In the first place, the kind of annatto is not mentioned; the quantity of water is not mentioned; the quantity of the leys of sub-carbonated potash is not mentioned;-and, by the way, what are the leys of sub-carbonated potash? are they a solution to saturation in water of sub-carbonate of potash? or-but we really do not understand. What, too, is aqua lixivum caustic? (a precious sample this of the patentee's latinity!) We suppose, however, that he means the liquor potassæ of the London Pharmacopoeia, or, in the language of the last century, soap leys. But the great discoverya liquid or solution of annatto-remains to be told. A solution of annatto! Gentle reader, if thou hast ever been so fortunate as to wear those very extraordinary and scarcely heard-of articles, yclept nankin trowsers or pantaloons, and thou wilt make inquiry of any wise and ingenious washerwoman, thou wilt find, to thy no small delight doubtless, that an article called NANKIN DYE (a solution of annatto in water by means of an alkaline salt) has been in common use by their ladyships, the washerwomen, for, at least, one quarter of a century; nay, we are not sure that some of the more grave and learned of that body were not acquainted with it fifty years ago; and, if thou desire to obtain this delectable liquid, we suppose it may be found at almost any oil shop or at the dyer's. However, if thou shouldst demand printed proof of such solutions, we refer thee at once to

* Aqua lixivia caustica. Vide Pharm. Edin. 1792.-Does the patentee mean this?

Martin and Grafton's, for a Spirit Black.

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the Family Cyclopædia, article Nankin Dye, in the Supplement; to Gray's Supplement to the Pharmacopoeia; and, lastly, to the Family Dyer and Scourer, by W. Tucker, where almost innumerable solutions of annatto may be found.

Whether the addition of aqua lixivum caustic—if we can find out what it is—and of alkohol, to the solution of annatto, will give the patentee an exclusive right to the vending of this nostrum, we do not pretend to say; but this patent, in sober seriousness, appears to us to be a sort of experiment upon the credulity and understanding of the age.

Inrolled, June, 1822.

To THOMAS MARTIN and CHARLES GRAFTON, of Birmingham, Warwickshire, for their Method of making fine light BLACK, of very superior colour, which, for distinction from other Blacks, they call Spirit Black. And a new Apparatus for producing the same.

THE object of producing this fine light black is principally for the manufacturing of printers' ink. The material commonly called lamp-black is a carbonaceous matter, usually prepared by burning oil or resinous substances, and collecting the sooty particles in a winding chimney. In the improved process, which forms the subject of this patent, the black is obtained by burning common coaltar, which should be divested, as much as possible, of the ammoniacal liquor and acid held in solution.

For this purpose, it is proposed that four casks should be employed, each capable of holding one hundred and thirty gallons, and into every one of them is to be put

about sixty gallons of the rough impure tar; to which an equal quantity of lime water is to be added, and then agitated by machinery or manual labour until the limewater is completely mixed with the tar. The vessels should then be suffered to rest for about six hours, by which time the tar will settle at the bottom of the casks, and the water may be drawn off. The casks containing the tar should then be filled with hot water, which may be supplied from the boiler of a steam engine, and the whole again agitated as before. This process may be repeated three times, suffering the tar to subside between each; and twelve hours should be allowed for settling from the last water, so that the whole of the tar and water may become separated, the water rising to the top of the cask, and the tar left at bottom, in a pure

state.

But, as some of the water will yet remain mechanically combined with the tar, it is proposed that the tar should be subjected to the process of distillation. For this purpose, a still, capable of holding one hundred and twenty gallons, may be employed, in which about fifty gallons at one time may be operated upon, when, by a gentle heat, the water, and other impurities which the tar may have retained, will be driven off. As soon as the water appears to have evaporated, and the spirit runs fine and clear, the process of distillation should be stopped, and, when cold, the pure tar may be drawn off, and set apart for the purpose of being employed as contemplated in the patent.

A

The tar thus purified may be now converted into black; or it may be subjected to further rectification to divest it of the mineral pitch or asphaltum which is combined with the oil and spirit: the latter is to be preferred; because the mineral pitch, or asphaltum, is only inflam