SECT. 4.-Amendment of a Patent.

A person who holds a patent, whether the original patentee or an assignee, may enter an Amendment with the clerk of the patents of England, Scotland, or Ireland, with consent of one of the law-officers of the crown of these countries respectively. The amendment may extend to " a Disclaimer of any part of either the Title of the invention or the Specification, stating the reason for such Disclaimer;" or a Memorandum of any Alteration in the said Title or Specification, not being such disclaimer or such alteration as shall extend the exclusive right granted by the said letters-patent." Such Amendment is considered a part of the Specification.

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Caveat may be lodged, giving the party a right to be heard against the Amendment before the Lord Advocate or other law-officer. The law-officer may require an advertisement to be made before he grants his consent to the amendment. No amendment can be pleaded in any action pending at the time when it is enrolled.1

SECT. 5.-The Invention.

It is a requisite of any invention for which a patent may be obtained, that it be complete of its kind, constituting when embodied a vendible article.2 It is held that the discovery of a mere principle cannot be protected,—a practical result in the form of an article of commerce, or a step towards the production of some known commodity, must be shown; and so, if one make a discovery in mechanics or chemistry, from which he expects great practical results to be attainable, while in the mean time he is unable to produce any, he cannot obtain a patent.3 It is no objection to the patent, however, that it is essentially for some principle in chemistry or natural philosophy, if it combine with the principle some special purpose and practical result. The invention must have been made by the claimant of the patent, and not suggested by another person. It must not have been used before, either by the petitioner or any other person. By "using" appears to be meant the employment for some article of trade. There are few cases in which one can avoid, in the literal sense, 66 using" an invention before it can be

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1 5 & 6 Wm. IV. c. 83, § 1. 7 & 8 Vict. c. 69, §§ 5, 6.- Holroyd, 33, et seq.-3 Ibid. 55.-4 Neilson v. Baird, 16th Nov. 1843.- Holroyd, 59. Godson, 38.- Holroyd, 18.-7 Godson, 40.

pronounced successful. So, in the case of the refracting glasses, Dolland, who obtained a patent, was entitled to retain it, though Dr Hall had invented the same commodity, as the latter had not "used it" by communicating the commodity to the public;1 the result would have been different had he used it as a vendible commodity, though he had concealed the method of construction.2 In one of the trials on the hot-blast case, it was laid down, "that the evidence must be sufficient to show that the actual invention, as disclosed and set forth in the specification, was not only discovered, but put to public use; that is, was publicly used and practised at a period prior to the date of the patent, and that no experiments, however nearly they may have approached to the discovery of the invention in the patent, can avail, unless that discovery had been perfected and actually applied to public use.' "3 It was held, in another of these cases, that to invalidate a patent, prior use must not only have been public, but must have been continued down to the time when the patent was obtained. It follows, that if several persons are in common aware of the same invention, no one of them can obtain a patent; but that, if several persons simultaneously make the same invention without communicating it to each other, or using it, he who first applies is entitled to a patent, to the exclusion of the others. It is sufficient to invalidate a patent for Scotland that the invention has been used in England.6

Confirmation. The law on this subject is to a certain extent modified by statute. If it be found by verdict of a jury that a patentee is not the first inventor of part or the whole of the subject of his patent, some other person having previously invented or used it, or if the patentee himself discover this to be the case, he may petition the Queen in Council to confirm his patent, or grant a new one. The Petition and Objections are heard before the Judicial Committee, who, if they are satisfied that the patentee believed himself to be the first inventor, and that the invention had not been publicly used before the date of his patent, may recommend that the petition be acceded to.7 When a patent comes under judicial discussion, and the decision is in favour of the patentee, the judge can give a certificate of the fact, the effect of which is,

1 Buller J. in Boulton v. Bull, 2 Hen. Bla. 487. See Lewis v. Marling, 10 Barn. & Cres. 22.-2 Case of Tennant, Davies' Patent Cases, 429.Neilson v. Baird, 16th Nov. 1843.- Neilson v. Househill Coal Company, 7th April 1842.- Holroyd, 18. Godson, 40.- Brown v. Annandale, 8th July 1841; affirmed, 1 Bell, App. 70.-75 & 6 Wm. IV. c. 83, § 2.

that if the validity be again questioned, the certificate may be produced, and if the decision be in favour of the patentee, he is to receive treble costs, unless the judge specially certify that he should not.1

Importation. It is specially provided in the English statute of James I., and would probably be held law in Scotland, that a patent may be obtained by the first user of a foreign invention. The above principles apply to such a case, and so a patent for a foreign machine was protected, though a model of the machine had been previously sent to England, the model not having been used.2

Utility. The invention must be useful and beneficial;— it would appear at first sight that there is little danger of a patent being disputed, unless the invention proves its utility by its vendibility, but a patent being held for a useless invention may be the means of preventing another person from applying that invention to some useful purpose.3 The invention must be completely new as to all material parts. It does not follow, however, that it must form a new article or commodity not previously known;-it may be a new arrangement of things already known, or simply an addition to, or an improvement of, something already in use. "An improvement on any known machine, whereby such machine is rendered capable of performing more beneficially," is a fit subject for a patent; and so is any skilful arrangement of common materials, so as to make them productive of some beneficial effect not previously occasioned by them, as in the case of Mr Hartley's method of arranging iron plates in buildings as a protection from fire. In such cases, however, the patent must be taken out only for the addition or improvement. In the nice case of Russell, it appeared that the conversion of flat iron into pipes for gas had been accomplished by letting the iron at a welding heat pass through the circular aperture made by the junction of two concave semicircular grooves on the surface of two cylinders, at right angles to their axles. A plan was adopted of welding by passing the hot iron through a die by the traction of a draw-bench. It was superior to the other method, and was found to be a sufficient invention to justify a patent. In the hot-blast case, on the other hand, the result produced was looked to; that result not however being a finished commodity, but only a

1 5 & 6 Wm. IV. c. 83, § 3. Lewis v. Marling, 10 Barn. & Cres. 22.3 Godson, 52. Webster, 10.- Holroyd, 33-35. Russell v. Crichton, 7th June 1839.5 Carpmael on Patents, 16.- Holroyd, 48.-7 Ibid. 98.Russell v. Crichton, 8th June 1839.

change in the elements employed in its structure tending to economize the manufacture. It was left to the jury to say whether the patentee had so described his process as to be unable to maintain that his patent applied to all varieties of the method of producing the effect; but it was held, that if he had not limited himself to any particular description of apparatus, it did not affect his patent that the same effect might be produced by other means, the object protected by the patent being the heating of the air of a furnace at a particular stage of the process of the manufacture of iron, viz. in its passage between the blowing apparatus and the furnace.1 It would appear that no person can obtain a patent for a mere improvement on a commodity for the making of which another person is in possession of a patent, at least to the prejudice of the patentee; and it is held " that where an improvement to a patent is made after the enrolment of the specification, it becomes the property of the patentee, provided that the improvement cannot be used of itself, but, to be useful, must be superadded to the patented invention."2

Though the applicant must be the sole inventor, it is not necessary that he must have gone through the process connected with the first construction with his own hands. "The rule of law respecting the assistance from servants may be thus stated. If the servant make a new discovery by himself, such invention becomes his property; but if the master plans and the servant only executes with alterations of his own, then the master is the true inventor of the machine." 113

A patent may be taken out for a combination of previously known machines or commodities, if the invention of the new combination be all that is claimed, or for an addition to any existing combination, if no more than the addition be taken credit for.4 "The application of a known substance or material to a new purpose, when there requires art to adapt it, is the subject of a patent."5 This is well illustrated by the case of the patent for percussion-locks. The detonating powder used for the purpose was well known before, but the patentee having first applied it as a priming for firearms, and used a lock adapted to the purpose, the application of locks of a different construction was held to be an infringement. It is observed that the use of the lock by the patentee, in this case, was necessary to convert his discovery into a vend

Neilson v. Househill Coal Company, 7th April and 15th Nov. 1842.* Carpmael, 53, 54.- Godson, 28. See Holroyd, 61.- Bovill v. Moore, 1816, 2 Marsh. 211. Lewis v. Davis, 1829, 3 Car. & Pay. 502.-5 Carpmael, 18.

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ible commodity, and that he could not have supported a patent for the mere application of certain well-known explosive mixtures as priming for firearms, without going into a detailed account of how that was to be done."1

SECT. 6.-The Title.

The title under which the patent is petitioned for is an object of great importance, as it is by the applicability of the title to the thing said to be invented that the lodger of a caveat knows whether the application will interfere with himself or not. It must convey an idea of what has been invented, but of nothing more. Thus, Lord Cochrane's patent for naphtha-lamps was found void, because it was called " a method or methods of more completely lighting cities, towns, and villages," whereas, though it was only for such a purpose that his invention could apparently be used, from the offensive nature of the materials, the invention was after all but a lamp suitable for the purpose of burning naphtha, and should, it was said, be called so.3 When Mr Wheeler invented a method of colouring porter by a small quantity of deep-coloured malt mixed with pale malt, instead of the old practice of preparing the whole malt of a certain depth of colour, and called the invention "a new and improved method of drying and preparing malt," it was said that there was no new method of drying and preparing malt in the invention, but merely a new way of colouring porter, and that it should have been called "a new method of preparing malt for the purpose of colouring beer or porter."

The title must not contain more uses for the commodity than those which it is adapted to; so Felton's patent in 1827 for "a machine for an expeditious and correct mode of giving a fine edge to knives, razors, scissors, and other cutting instruments," was held bad, because the machine described would not sharpen scissors.5

SECT. 7.-The Specification.

The preparation of the Specification, which, as already mentioned, the patentee must enrol, is of the most material consequence. "The invention must be accurately ascer

1 Carpmael, 20.-2 Ibid. 40.-3 Cochrane v. Smethurst, 1 Stark, 205. Carpmael, 42-4 The King v. Wheeler, 1819-C. J. Abbot, 2 Barn. & Ald. 345.-5 Holroyd, 94.