new inventions, like other royal grants, were regarded as proceeding ex speciali gratia, and mero motu of the crown. Being likewise in their nature a restriction upon general trade, they were little favoured by our best lawyers, but considered as grants of the crown, in some degree at the expence of the subject. They were, therefore, according to the equity of all grants of the sovereign, interpreted with the greatest strictness, and the law gave as little as was consistent with the faith of the royal word. But in the improvement of manufactures, and in the more guarded exercise of the prerogative, patents have assumed a more beneficial form and character. They are thus a kind of copyright of trade. The property and exclusion are given to the inventor, for the public benefit; to reward him and encourage others. This is the present legal acceptance of patents for new inventions. It may be useful to give a brief view of the law upon this subject. Our plan necessarily confines us to principles, as collected from, and supported by, authorities.

Patentees for new invenions are left by the stat. 21 Jac. 1. c. 3., to the common law, and the remedies which

follow the nature of their rights but to render their patents valid, all the conditions required by the above statute must be observed. That statute condemns all monopolies ; but the 5th and 6th sections save letters patent, and grants of privileges of the sole working and making of any new manufacture within this realm, to the first and true inventor, so that they be not contrary to the law, or mischievous to the state. The word manufacture is of most extensive meaning, and applies not only to things made, but to the practice of making; to principles carried into practice in a new manner; and to new results of principles carried into practice.

The questions which generally arise upon patents are1st. Whether the subject, for which the monopoly is claimed, were a known invention, and in use before the patent. 2nd. Whether the specification be sufficient to enable others to make it up, in a mode as beneficial as that which is made use of by the inventor himself. The meaning of the specification is, that others may be taught to do the thing for which the patent is granted; and that, after the term, the public shall have the benefit of the discovery.

If the specification, therefore, be false, or there be any concealment, either in the principles and composition, or the mode of operation, the patentee is guilty of a fraud upon the public rights; his specification is false, and his patent void. Therefore, in a patent for trusses for ruptures, the patentee omitted what was very material for tempering steel, which was rubbing it with tallow, and for want of that Lord Mansfield (Bull. N. P. 76.) held the patent void.

In the King v. Arkwright, which was a scire facias to repeal a patent, Buller J. lays down these rules :—1. A man, to entitle himself to a patent, must disclose his secret, and specify his invention, in such a way, that others of the same trade, who are artists, may be taught to do the thing for which the patent is granted, by following the directions of the specification, without any new invention or addition of their own.-2. He must so describe it, that the public may, after the expiration of the term, have the use of the invention in as cheap and as beneficial a way as the patentee himself uses it; and, therefore, if the specification describe many parts of an instrument, or machine, and the patentee

himself uses only a few of them, or does not state how they are to be put together, or used, the patent is void.—3. If the specification be in any part of it materially false and defective, the patent is against law, and cannot be supported. Bull. N. P. 77.

When it appears that the patentee has made a full and fair discovery, he is entitled to the protection which the law gives him. But where the discovery is not fully made, the law will prevent any imposition on the public, and vindicate its rights. Slight grounds will be sufficient to vacate the patent, as in the case of the patent for steel trusses, already cited. The patentee, therefore, should give a specification of the invention in the clearest and most unequivocal terms of which the subject is capable; and if it appear that there be any unnecessary ambiguity, affectedly introduced into the specification, or any thing which tends to mislead the public, in that case the patent is void. So, if the patentee say, that by one process he can produce three things, and he fails in one. Turner v. Winter, 1 T. R. 602. So, if the specification direct the same thing to be produced several ways, or by

several different ingredients, and any one of them fail. ibid.

As to the invention, the rule of law is very different from what it is in the specification; for with regard to the specification, if any one part of the invention be not sufficiently described, the whole patent is void; but, as respects the invention, if any one part of it be new and useful, that is sufficient to sustain a patent for the particular object of the invention. But the patent must not be more extensive than the invention. Therefore, if an invention consist in an addition or an improvement only, and the patent is for the whole machine or manufacture, it is void. The King v. Else, Bull. N. P. 76.

In Morris v. Brandon, the question was, whether an addition to an old stocking-frame was the subject of a patent. Lord Mansfield said, if the general question of law, viz. that there can be no patent for an addition, be with the defendant, that objection would go to repeal almost every patent that was ever granted. There was a verdict for the plaintiff, which was acquiesced in. Bull. N. P. 77. " Since that time it has been the general received opinion in Westminster Hall, that a patent for

an addition is good, but then it must be for the addition only, and not for the whole machine." Per Buller, J. in Boulton v. Bull, 2 Henry Black. 489.

In the last case, which was in the Comm. Pl. that court was equally divided, whether a patent for a new invented method of using an old engine in a more beneficial manner than heretofore, by the employment of certain principles, was valid or not. Afterwards another action was brought upon the same patent, and a general verdict having been found for the plaintiffs, and judgment given for them by the Court of Common Pleas, the defendants brought a writ of error in K. B. It may be necessary to state the case more fully, as it is the leading case upon the subject.

It was a patent to A. for his method of lessening the consumption of steam and fuel in fire-engines: the specification stated, that the method consisted of the following principles "[describing the mode in which these principles were applied to the purposes of the invention]" afterwards an Act of Parliament was passed to extend the patentees' term, the title of which was, An Act for vesting the sole property, &c.