by the act 15 Geo. 3 c. 61. Not good in law, because it did not fall within the construction of the statute, 21 Jac. 1. c. 3. against monopolies; which, in excepting letters patent, speaks of them as patents for the sole working or making, of any manner of new manufactures; which is descriptive either of the practice of making a thing by art, or of the thing when made; and that therefore, for a mere principle, without having carried it into effect, and produced some new-found matter or substance, a patent cannot be good that the patent was not continued the act 15 Geo. 3. c. 61.* it was shown that

*The act was entitled "An act for vesting in J. Watt, his executors, &c. the sole use and property of steam engines, commonly called fire engines, of his invention ;" described in the said act for a limited time.

It recited that the king had, by letters patent, 5 Jan. 9. Geo. 3. granted to Watt, his executors, &c. the sole benefit and advantage of making, and vending certain engines, by him invented for lessening the consumption of steam and fuel in fire engines, for fourteen years, &c." on condition that he should enrol a specification, &c. that Watt had accordingly enrolled a specification of the said engine, (which specification was then set forth as above.) It farther recited that Watt had employed many years, and a considerable part of his fortune, in making experiments upon steam and steam engines, commonly called fire engines, with a view to improve them; by which several considerable advantages over the common steam engines, are acquired; but on account of the many difficulties which arise in the execution of such large and complex machines, and of the long time requisite to make the necessary trials; he could not complete his intention before the end of the year 1774; when he finished some large engines as specimens of his con

the title of the act was for vesting in the plaintiff Watt, the sole property of certain steam engines, called fire engines, of his invention; which, after reciting and taking notice among other things, that the king had, by his letters patent, granted to Watt the sole benefit and advantage of making, constructing, and selling the engines, therein before particularly described; shall be vested in Watt for twenty-five years. It was therefore contended, that if the patent was really for princi

struction, which had succeeded so as to demonstrate the utility of the invention; and in order to manufacture these engines with accuracy, and so that they might be sold at a moderate price, a considerable sum of money must be previously expended in erecting mills, and other apparatus; and that several years and repeated proofs would be required, before any considerable part of the public could be convinced of the utility of the invention, and of their interest to adopt the same: the whole term granted by the letters, might probably elapse, before Watt could receive an advantage adequate to his labour and invention; and then it enacted, that from and after passing of the act, the sole privilege and advantage of making, constructing, and selling the said engines, herein before particularly described, within the kingdom of Great Britain, and his Majesty's colonies and plantations abroad; should be, and were thereby vested in Watt, his executors, administrators; and assigns, for and during the term of twenty-five years; and it prohibited any other person's making, using, and putting into practice the said invention; or counterfeiting, or imitating the same; or making any addition to, or subtraction from it, without Watt's licence, &c. with a proviso, that the act should not extend to prevent any person's making any fire or steam engine, or any contrivance relating to the same, which was not the invention of Watt; or which had been publicly used before.

upon

ples, it was not continued by the act; or supposing it to be well continued, as being described according to its import, it would not be within the protection of the statute against monopolies, for the foregoing reasons. 2ndly, the act itself it was argued, that the recital that the king had granted a patent for making and vending certain engines, was false: and it had been adjudged, that if a private act of parliament, like the present, be founded upon a false recital, the act is void. 3dly, that if the subject was viewed as arising from the patent and act, taken together, the arguments respecting these instruments, separately, applied more strongly, inasmuch as if the act was to be considered as explanatory of the patent, or as a part of it; there could not be a doubt but that it meant to grant a monopoly for a formed engine or machine. That upon the whole of the case, it appeared either that the patent was for an entire formed machine, when it ought to have been for an im‐ provement only; and in which case, the specification did not correspond with it: or it was for mere principles, which according to the statute of 21 Jac. 1. c. 3. against monopolies, could not be the subject of a patent. The case was very elaborately argued on both sides; and after full consideration, the judges gave their respective opinions.

Rooke J. The objections are merely formal; they do not affect the substantial merits of the patentee, nor the meritorious consideration which the public have a right to receive in return for the protection which the patentee claims. With regard to the first objection, it is, that the patent is not for a fire engine of a particular construction, but for a new invented method. It pre-supposes the existence of the fire engine, and gives a monopoly to the patentee of his new invented method of lessening the consumption of steam and fuel in fire engines. The obvious meaning of these words is, that he has made an improvement in the construction of fire engines; for what doth method mean, but mode or manner of effecting? What method can there be of saving steam, or fuel in engines, but by some variation in the construction of them? A new invented method, therefore, conveys to my understanding, the idea of a new mode of construction. I think these words are tantamount to fire engines of a newly invented construction: at least I think they will bear this meaning, if they do not necessarily exclude every other. If they will bear this interpretation, then I think the objection, which is merely verbal, is answered: to which I add, that patents for a method, or art of doing particular things, have been so numer

ous, that method may be considered as a common expression in instruments of this kind. It would therefore be extremely injurious to the interest of the patentees to allow this verbal objection to prevail. As to the second objection, that no particular engine is described, that no model or drawing is set forth; I hold this not to be necessary; provided the patentee so describes the improvement, as to enable artists to adopt it when his monopoly expires. The jury find he has so described it. It is objected that he professes to set forth principles only; but we are not bound by what he professes to do, but what he has really done. If he had proposed to set forth a full specification of his improvement, and had not set it forth intelligibly, his specification would have been insufficient, and his patent void. It seems, therefore, but reasonable, that if he sets it forth intelligibly, his specification should be supported; though he professes only to set forth the principle. The term principle, is equivocal: it may denote either the radical elementory truths of a science, or those consequential axioms, which are founded on radical truths; but which are used as fundamental truths by those who do not find it expedient to have recourse to first principles. The radical principles on which all steam engines