by the parties, or the agents of the parties, who, intending to make an accurate enrolment, have by mere inadvertence made an enrolment which was not what it purported to be, a true statement of that which the party intended at the time; and not only has strict evidence of error been required, but in order to enable any third party to dispute the validity of the amendment and of the order, it has been directed that the order itself should be endorsed on the enrolment.

It does not appear that the Master of the Rolls, as Keeper of the Records in Chancery, has ever exercised any greater authority than I have stated in matters of this kind; and being of opinion that I have no jurisdiction to make any such order as is asked by this petition, I must dismiss the petition with costs.

Petition dismissed.

The following was the form of the fiat in the above case: "To the Clerk of the Patents for England. This is to certify that John Sharp, of Dundee, in the county of Forfar in Scotland, flax-spinner, hath applied to me for leave to enter with you the above written memorandum of alteration of part of the specification of a certain invention, for which letters patent were duly granted to him under the great seal, dated at Westminster, October 8, 1836, the specification of which was duly enrolled on April 8, 1837; and on considering the said application I directed him to advertise his said alterations in the London Gazette, and in the Times and Morning Chronicle, and the Dundee Courier, newspapers. And such advertisements have been duly made in the Gazette, Times and Morning Chronicle, on August 24 last past, and in the Dundee Courier of the 28th day of the same month, and no objection having been made to the said application, I have accordingly granted leave to the said John Sharp to file his said memorandum of alterations, pursuant to the statute passed in the sixth year of the reign of his late Majesty, entitled 'An act to amend the law touching letters patent for inventions.'-Signed R. M. ROLFE."

In Re Whitehouse (1 ante, p. 428) a patent dated February 26, 1825, "for improvements in manufacturing tubes for gas and other purposes;" by the order, made January 13, 1830, of the Master of the Rolls, on the petition of James Russell, stating the error to be a clerical one, and to have arisen in the engrossment of the specification, as appeared by the original draft from which the engrossment was made, and on the affidavit of the agent, it was ordered "that the proper officer do amend the original roll or entry of the said specification remaining of record in the Enrolment Office of this court, by altering the letter 'w' in the said word wire' to the letter 'f,' so that the same may read 'fire.'" In Re Rubery's Patent, granted November 14, 1837, for "certain improvements in the manufacture of part of the furniture of an umbrella," the specification recited the letters patent to have been granted in "October' instead of "November." Lord Langdale, M. R., ordered the amendment as prayed. (1 Web. P. C. 649, note.) In both these cases the petition stated that no scire facias to repeal the patent, or other proceedings at law on the patent, had been instituted. In Re Redmund (1 ante, 1. 397) the petition stated that within the last month the petitioner had discovered that the copying clerk, in engrossing the specification and the plan annexed to it, had by mistake transposed the numbers by which in the specification reference was made to the plan, and that no office copy of the specification had been taken. The petition prayed that this clerical error in the enrolment might be amended. Ordered as prayed.

NEILSON v. THOMPSON.

Chancery, V. C., Dec. 24, 1840.

(1 Web. P. C. 275.)

Evidence of Patentee's Right. Infringement. Injunction Pending Suit.

Enjoyment for twelve years, held to make a prima facie case for injunction. Evidence of infringement.

Bill for injunction against infringement.

The patent was granted September 11, 1828, numbered 5,701, to J. B. Neilson, "for the improved application of air to produce heat in fires, forges and furnaces, where bellows or other blowing apparatus are required."

The specification was as follows: "A blast or current of air must be produced by bellows or other blowing apparatus in the ordinary way, to which mode of producing the blast or current of air this patent is not intended to extend. The blast or current of air so produced is to be passed from the bellows or blowing apparatus into an air vessel or receptacle made sufficiently strong to endure the blast, and through or from that vessel or receptacle by means of a tube pipe or aperture into the fire, forge or furnace. The air vessel or receptacle must be air-tight, or nearly so, except the apertures for the admission and emission of the air, and at the commencement and during the continuance of the blast it must be kept artificially heated to a considerable tempera

It is better that the temperature be kept to a red heat or nearly so, but so high a temperature is not absolutely necessary to produce a beneficial effect. The air vessel or receptacle may be conveniently made of iron, but as the effect does not depend upon the nature of the material, other metals or convenient materials may be used. The size of the air vessel must depend upon the blast and on the heat necessary to be produced. For an ordinary smith's fire or forge, an air vessel or receptacle capable of containing

twelve hundred cubic inches will be of proper dimensions, and for a cupola of the usual size for cast-iron founders, an air vessel capable of containing ten thousand cubic inches will be of a proper size. For fires, forges or furnaces, upon a greater scale, such as blast furnaces for smelting iron and large cast-iron founder's cupolas, air vessels of proportionably increased dimensions and numbers are to be employed. The form or shape of the vessel or receptacle is immaterial to the effect, and may be adapted to the local circumstances or situation. The air vessel may generally be conveniently heated by a fire, distinct from the fire to be affected by the blast or current of air, and generally it will be better that the air vessel and the fire by which it is heated should be enclosed in brickwork or masonry, through which the pipes or tubes connected with the air vessel should pass; the manner of applying the heat to the air vessel is, however, immaterial to the effect, if it be kept at a proper temperature."

In the subsequent proceedings on the above, as well as on Crane's patent, the following inventions relating to the application of air to furnaces are frequently referred to :

Letters patent, January 2, 1828, to Thomas Botfield, for "certain improvements in making iron, or in the method or methods of smelting and making iron.”

Specification. "I, the said Thomas Botfield, do hereby declare that the following is a particular description of the nature of my said invention, and methods and improvements in the smelting and making of iron, both in respect to principle, and the way and manner in which the same may be performed—that is to say, the principle is for causing or obtaining a blast of atmospheric air sufficient to smelt, fuse, run or make pig, cast or crude iron, from ironstone or ore. This blast is to be produced by means of rarefied air, gas, flame or heated air, from an oven or fireplace, and is to be applied in or to a blast furnace, cupola or air furnace; this I propose to effect by the draught of a powerful chimney or chimneys, which may be built separate at any distance that may be most convenient, or may join to or be made part of the blast furnace or cupola, as may be

found most desirable and best to answer the purpose required, and which is to be connected by a flue or flues with the cupola, blast or air furnace; but in case this draught should not prove sufficient for the purpose of smelting the iron-stone or ore, I propose and intend to apply and use the common blast from machinery to assist the blast from the draught of the chimney; this is to be used at the same or any other twire. And I claim a right and mean to use the atmospheric air, either separate or mixed with gas, flame or heated air; I also claim as part of my patent the right to use and mix (with other materials) rock salt, common refuse or other salt, in any state or degree of refining, or any other substance of which soda (the mineral alkali) forms a part; this is to be mixed in the blast furnace, cupola or air furnace, with the iron-stone or ore, and with the other usual materials of coke, or charcoal and limestone, to which cinder (produced in the processes of converting pig, cast or crude iron into malleable iron) may be added. And I propose to mix the salt or other substance containing soda in such proportions as I shall find necessary to cause the iron stone or ore to melt or fuse sooner, or with less blast, fuel or heat. Now I do hereby declare that the before-mentioned principles comprehend the real object of my patent; and in order for the better understanding the method or methods in which the aforesaid may be reduced and applied to practical use, I wish to be understood, that although I may vary the mode, way and manner by a variation of applications to produce the said effects, and maintain the main purpose intended as circumstances may require, yet I principally propose to adhere to the method or methods herein described, which may be understood from the annexed drawing and description thereof."

The specification then describes the drawing, which shows a tall chimney on one side of the ordinary blast furnace, and connected with it by flues at the top and at the bottom.; on the other side an oven or fireplace, with a flue to admit the air from the oven or fireplace to the twire; also a passage along the top of that flue for the atmospheric air to the twire; the top of the blast furnace was provided with a