nuity, and the author gets the monopoly for a certain term. It signifies nothing to either, whether the patent be for the engine so made, or for the method of making it, if that method be sufficiently described in the specification. Upon these grounds, with that deference which I ought to feel upon a subject with which I do not profess myself to be much conversant, my opinion is, that the judgment of the Court of Common Pleas ought to be affirmed. Mr. Justice LAURENCE.-Two objections have been made by the plaintiffs in error; first, that this is not an invention for any formed or organized machine, instrument, or manufacture, but of mere principles only: secondly, that the specification is bad. As to the first, the claim of the plaintiffs below is founded on the proviso in the statute of James, which allows the crown to grant patents in favour of new manufactures, and therefore it must rest on the ground of Watt's having invented some new manufacture. If it were necessary to consider, whether or not mere abstract, principles are the subject of a patent, I should feel great difficulty in deciding that they are: but that consideration is unnecessary on the present occasion, because, by looking at the patent and the recital in the act of parliament, it appears that Watt applied for and obtained a patent for an engine or mechanical contrivance, for lessening the consumption of steam in fire-engines. The letters patent recite that he had invented a method of lessening the consumption of steam, and grant to him the sole right of using the said invention for fourteen years. In order to see what the invention was, it is necessary to refer to the specification; that states what the invention is, and that the method consists in certain principles, as they are called, which are described in the specification. Then followed the statute, which, after reciting that the king had granted to Watt the sole benefit of making and vending certain engines, invented by him, for lessening the consumption of steam in fire-engines, and that there was enrolled in the Court of Chancery a description of the said engine, vests in him the sole right of making and selling the said engines for twentyfive years. From this, therefore, it is clear, that the legislature understood that the patent was for an engine for some mechanical contrivance, and the form of the patent and the specification does not contradict this. "Engine" and "method" mean the same thing, and may be the subject of a patent. "Method," properly speaking, is only placing several things, and performing several operations in the most convenient order: but it may signify a contrivance or device; so may an engine, and therefore I think it may answer the word "method." So " principle" may mean a mere elementary truth, but it may also mean constituent parts and in effect the specification is this, "the contrivance by which I lessen the consumption of steam, consists in the following principles," (that is, constituent or elementary parts;)" a steam vessel, in which the powers of steam are to operate, to be kept as hot as the steam by a case; a distinct vessel to condense the steam; and pumps to draw off such vapour as is likely to impede the motion of the fire-engine," &c. That is the description of the thing when put into different language. Then taking this to be a patent for an engine, it is objected that the specification is bad. In considering that question, it is necessary to see for what Mr. Watt has obtained his patent: he does not claim it for an improvement to a fire-engine for any particular purpose, e. g. for raising water out of mines, or any other specific thing; but his claim is generally to an invention for lessening the consumption of steam applicable to all fire-engines for whatever purpose they may be used, and whatever may be their construction, by an alteration of, and addition to, parts which are common to all, and upon which their powers of working depend. The objection that requires a more full description of the engine, goes the length of requiring a description of every engine that is acted upon by the force of steam. But I do not think that if his specification had been so comprehensive, his invention would have entitled him to a patent for the sole vending and making the whole engine so altered and improved; for such a patent would have been more extensive than the thing invented: the patent must be supported, as granted for an improvement and addition to old engines, known and in use, and I think that the patent is good in this point of view. For Watt claims no right to the construction of engines for any determinate object, except that of lessening the consumption of fuel in such pre-existing engines, and for nothing else. In the argument, the engine to diminish the consumption of steam was confounded with that which was intended to improve. Some of the difficulties in the case have arisen from considering the word engine in its popular sense, namely, some mechanical contrivance to effect that to which human strength, without such assistance, is unequal; but it may also signify "device," and that Watt meant to use it in that sense, and that the legislature so understood it, is evident from the words "engine" and "method," being used as convertible terms. Now there is no doubt but that for such a contrivance a patent may be granted, as well as for a more complicated machine; it equally falls within the description of a "manufacture," and unless such devices did fall within that description, no addition or improvement could be the subject of a patent. If this be so, it only remains to be considered, whether or not for the improvement of fire-engines, Watt has with sufficient accuracy stated a definite alteration or addition, which may be made in all fire-engines, in such a way as to enable a workman to execute it; and it seems to me that he has; for he has directed him to make a vessel for the condensation, distinct from that in which the powers of steam operate, and to convey the steam as occasion requires, from the cylinder to the condensing vessel, to keep the cylinder hot by means distinctly described, and to extract by pumps the vapour which may impede the work; therefore it seems to me, that he has given distinct directions for the purpose: whe ther those directions were or were not sufficient, is not now a question for our decision; it was a question for the determination of the jury, and they have decided it. Judgment affirmed. IN THE COURT OF COMMON PLEAS. John and Charles Cartwright v. Amatt and another. 18th November, 1799. THIS was an action on the case for the infringement of a patent. The declaration, after stating the grant of letters patent to one Edmund Cartwright, the inrolment of the specification, &c. proceeded to aver, that the said Edmund Cartwright, afterwards and before the committing the grievances after mentioned, by a certain indenture made between the said Edmund Cartwright of the first part, the plaintiffs of the second part, and certain other persons therein mentioned and referred to of the third and fourth parts, did, for the considerations therein mentioned, assign and set over unto the plaintiffs, their executors, &c. the before mentioned letters patent, saving, excepting and reserving unto the said Edmund Cartwright, his executors and administrators, until the final determination and conclusion of a certain suit then depending, and now long since ended and con |