Lords.

In the House of of air to fires, to acquire the agent which he intends to actheat in the blast, instead of a cold blast. The mode in which you are to heat, the form and shape, dimensions and numbers, of the vessels, he does not claim or intend to prescribe—he does not claim or intend to describe-he does not claim. If in that stage, by so intercepting the air and heating it, you pass the blast into the furnace, that is, he says, my improved application of air-that is the agent I mean to use, in order to produce heat in the furnace. How you heat, in what mode, or in what vessel, provided the vessel be strong enough to endure the blast, and of cubical contents of air sufficient for the blast, I neither care nor direct you; for if you so get the hot blast into the furnace, by heating the air in a vessel between the blowing engine and the fire, you attain my object; you will get my improved application of air.

scribed.

The specifica- I am therefore of opinion, and must give you in point of law tion claims nothe direction, that the specification does not claim any thing as thing in respect of the details of to the form, nature, shape, materials, numbers, or mathematical the mode de- character, of the vessel or vessels in which the air is to be heated, or as to the mode of heating such vessels, provided the blast is heated between the blowing apparatus and the furnace, in an air vessel or receptacle, as to the size, dimensions, and numbers, of which you must suit yourself.

But within this objection, which is one of law, the defenders urge, that even if Neilson does not claim the air vessel as part of his invention, he has so described it as to make one particular sort of vessel a part of his apparatus, and has limited himself to one sort of air vessel, viz. one large vessel, to be increased in size according to the extent of blast, that is, of air to be heated. They say, that is the meaning of the specification-that practical men would so understand it; that this is so clearly the only vessel that Neilson contemplated, that his invention does not apply to any vessels in the shape of tubes, pipes, &c. In short, on this view of the specification they say, not very consistently with a great part of their case, that the specification contains really a very special, limited, and restricted description, by which the inventor so described one sort of apparatus, that he cannot claim any other, or maintain that his patent is one which applies to all varieties in the mode of heating air. This is a question for you; it is a question on the meaning and intelligibility of the specification-it is embraced under the issues, for you to It is involved in the second and third issues. But 1 also propose to ask you to answer a special question on that point, which I shall afterwards state to you. If either party holds this to be a question for the court, I shall also state my own opinion, if required, so that the verdict, if according to the evidence, would stand, if it is a point for the jury; if for the court, the point would be fairly raised. But at the same time

answer.

that this view is pressed by the defenders, and much evi- A.D. 1843. dence adduced, to convince you that such is the only practical view which can be taken of the specification, there is another view taken, of a totally opposite description, which is a question of law for the court. The defenders say,-the specification seizes hold of an abstract principle, viz. that hot air produces more heat than cold, and of that abstract principle alone that the patentee purposely avoids any mode of stating how the principle should be applied; hence that the patent is bad, as being one for a principle alone.

The defenders, you will recollect, were very reluctant to state whether they actually raised that point or not. I think it is at the foundation of their whole case, and sure I am, that to enable you to discharge your duty, it is very necessary that I should not in any way avoid that question of law, or turn my remarks on it, which I easily could, into observations in point of fact, which the defenders could not except to; I think it will be more useful to you for me to explain the law to you fully on this point, and the defenders have thus the benefit of being able to except to any thing I say, and so obtain the judgment of the court on the point, in case I am wrong.

It is quite true that a patent cannot be taken out solely for The discovery an abstract philosophical principle-for instance, for any law of of a principle not the subject nature, or any property of matter, apart from any mode of of a patent, but when applied it turning it to account in the practical operations of manufacture, becomes an inor the business, and arts, and utilities of life. The mere discovery vention which may be paof such a principle is not an invention, in the patent law sense tented. of the term. Stating such a principle in a patent may be a promulgation of the principle, but it is no application of the principle to any practical purpose. And without that application of the principle to a practical object and end, and without the application of it to human industry, or to the purposes of human enjoyment, a person cannot in the abstract appropriate a principle to himself. But a patent will be good, though the subject of the patent consists in the discovery of a great, general, and most comprehensive principle in science or law of nature, if that principle is by the specification applied to any special purpose, so as thereby to effectuate a practical result and benefit not previously attained.

The main merit, the most important part of the invention, may consist in the conception of the original idea-in the discovery of the principle in science, or of the law of nature, stated in the patent, and little or no pains may have been taken in working out the best manner and mode of the application of the principle to the purpose set forth in the patent. But still, if the principle is stated to be applicable to any special purpose, so as to produce any result previously unknown, in the way and for the objects described, the patent is good. It is no longer

Lords.

A principle reduced to prac

tice is the subject of letters

extensive may

claim.

a

In the House of an abstract principle. It comes to be a principle turned to account, to a practical object, and applied to a special result. It becomes, then, not an abstract principle, which means a principle considered apart from any special purpose or practical operation, but the discovery and statement of a principle for special purpose, that is, a practical invention, a mode of carrying a principle into effect. That such is the law, if a well-known principle is applied for the first time to produce a practical result for a special purpose, has never been disputed. It would patent, however be very strange and unjust to refuse the same legal effect, when be the resulting the inventor has the additional merit of discovering the principle as well as its application to a practical object. The instant that the principle, although discovered for the first time, is stated, in actual application to, and as the agent of, producing a certain specified effect, it is no longer an abstract principle, it is then clothed with the language of practical application, and receives the impress of tangible direction to the actual business of human life. Is it any objection then, in the next place, to such a patent that terms descriptive of the application to a certain specified result include every mode of applying the principle or agent so as to produce that specified result, although one mode may not be described more than another-although one mode may be infinitely better than another-although much greater benefit would result from the application of the principle by one method than by anotheralthough one method may be much less expensive than another? Is it, I next inquire, an objection to the patent, that, in its application of a new principle to a certain specified result, it includes every variety of mode of applying the principle according to the general statement of the object and benefit to be attained? You will observe that the greater part of the defenders' case is truly directed to this objection. This is a question of law, and I must tell you distinctly, that this generality of claim, that is, for all modes of applying the principle to the purpose specified, according to or within a general statement of the object to be attained, and of the use to be made of the agent to be so applied, is no objection whatever to the patent. That the application or use of the agent for the purpose specified, may be carried out in a great variety of ways, only shows the beauty, and simplicity, and comprehensiveness of the invention. But the scientific and general utility of the proposed application of the principle, if directed to a specified purpose, is not an objection to its becoming the subject of a patent. That the proposed application may be very generally adopted in a great variety of ways, is the merit of the invention, not a legal objection to the patent.

The defenders say--you announce a principle, that hot air will produce heat in the furnace; you direct us to take the

blast without interrupting or rather without stopping it, to A.D. 1843. take the current in blast, to heat it after it leaves the blast, and to throw it hot into the furnace. But you tell us no more— you do not tell us how we are to heat it. You say—you may heat in any way, in any sort of form of vessel. You say I leave you to do it how you best can. But my application of the discovered principle is, that if you heat the air, and heat it after it leaves the blowing engine (for it is plain you cannot do it before), you attain the result I state; that is the purpose to which I apply the principle. The benefit will be greater or less. I only say, benefit you will get, I have disclosed the principle; I so apply it to a specified purpose by a mechanical contrivance, viz. by getting the heat when in blast, after it leaves the furnace; but the mode and manner, and extent of heating, I leave to you, and the degree of benefit, on that very account, I do not state. The defenders say, the patent, on this account, is bad in law. I must tell you, that taking the patent to be of this general character, it is good in law. I state to you the law to be, that you may obtain a patent for a mode of carrying a principle into effect; and if you suggest and discover, not only the principle, but suggest and invent how it may be applied to a practical result by mechanical contrivance and apparatus, and show that you are aware that no particular sort or modification, or form of the apparatus, is essential, in order to obtain benefit from the principle, then you may take your patent for the mode of carrying it into effect, and are not under the necessity of describing and confining yourself to one form of apparatus. If that were necessary, you see, what would be the result? Why, that a patent could hardly ever be obtained for any mode of carrying a newly discovered principle into practical results, though the most valuable of all discoveries. For the best form and shape or modification of apparatus, cannot in matters of such vast range, and requiring observation on such a great scale, be attained at once; and so the thing would become known, and so the right lost, long before all the various kinds of apparatus could be tried. Hence you may generally claim the mode of carrying the principle into effect by mechanical contrivance, so that any sort of apparatus applied in the way stated will, more or less, produce the benefit, and you are not tied down to any form.

The best illustration I can give you, and I think it right to give you this illustration, is from a case as to the application of that familiar principle the lever to the construction of chairs, or what is called the self-adjusting lever (g). This case, which afterwards came under the consideration of the whole court, was

(g) Minter's patent, ante 126 & 134.

Lords.

In the House of tried in the Court of Exchequer during the presidency of Lord Lyndhurst. The case was as to the patent reclining chair, the luxury of which some of you may have tried; it had a selfadjusting lever, so that a person sitting or reclining, and I need not tell you what variety of postures can be assumed by a person reclining in a chair-in whatever situation he placed his back, there was sufficient resistance offered through means of the lever, to preserve the equilibrium. Now any thing more general than that, I cannot conceive; it was the application of a well-known principle, but for the first time applied to a chair. He made no claim to any particular parts of the chair, nor did he prescribe any precise mode in which they should be made (h); but what he claimed was a self-adjusting lever to be applied to the back of a chair, where the weight of the seat acts as a counterpoise to the back, in whatever posture the party might be sitting or reclining. Nothing could be more general. Well, a verdict passed for the patentee, with liberty to have it set aside; but Lord Lyndhurst and the rest of the court held, that this was not a claim to a principle, but to the construction of a chair on this principle, in whatever shape or form it may be constructed (i). Just so as to the hot blast, only the principle is also new. The patentee says, "I find hot air will increase the heat in the furnace, that a blast of hot air is beneficial for that end." Here is the way to attain it-"heat the air under blast, between the blowing apparatus and the furnace; if you do that, I care not how you may propose to do it—I neither propose to you, nor claim, any special mode of doing it; you may give the air more or less degrees of heat; but if you so heat it, you will get by that contrivance the benefit I have invented and disclosed, more or less, according to the degree of heat." This is very simple, very general; but its simplicity is its beauty and its practical value-not an objection in law (k).

Having now stated the general law to you, there are some further practical directions in point of law, which may very usefully aid you in considering the case, and the issues under which it is tried. The first practical direction I have to give you, is as to the meaning of the pursuer's issue. "Whether in the course of the year 1840, and during the currency of the said letters patent, the defenders did, in or at their iron works at Househill, by themselves or others, wrongfully, and in contra

(h) The specification was accompanied by drawings, showing various modes of constructing a chair on this principle, but the claim was in the general form above suggested. Ante 126.

(i) In Minter v. Wells, ante 134.

(k) The learned judge referred to the judgment of the Court of Exchequer as to the invention claimed, ante 371; and as to the meaning of the term effect,' ante 372, expressing his opinion

that the meaning of the term effect' was for the jury, but that (referring to Astley v. Taylor, Shaw's Ap. C. 58.) if either of the parties wished it, he should state his opinion upon it. The learned judge was not asked for his opinion, and he left a special question to the jury upon it, and both parties appear to have treated it as a question for the jury. An exception directed to this point was disallowed.