more thicknesses of suitable porous fabrics, to allow the air under pressure to pass out, deprived of the flour, by means of this filtration. I also obtain the same result by placing the filtering chamber between the stone case or chamber receiving the meal and dust from the stones and the exhausting machine. The stive or dusty air is then sucked through the filtering fabrics, instead of being blown through, and the air passes away clean as before." The utility of the patent was not in dispute. It appeared by a report of the Government officials at the victualling-yards that it enabled more than twice the quantity of wheat to be ground in a given time by a given number of stones; that it produced both more and better flour from a given amount of corn; that it made the stones last longer; and that it purified the atmosphere of the mill. In 1856 the plaintiff brought the action of Bovill v. Keyworth against certain millers for infringing his patent. The defendants to that action pleaded the usual pleas, denying the novelty and utility of the invention, the sufficiency of the specification, and the infringement. A verdict was given for the plaintiff for the full amount claimed, and the Lord Chief Justice Campbell certified that the validity of the patent had come into question, and been proved. A rule nisi was obtained to enter the verdict for the defendants or for a new trial, on the ground that the second part of the patent as described in the specification, could not be made the subject of a patent, that the specification was insufficient, and that the verdict was against the evidence, with respect to the prior use of the alleged invention. This rule was discharged on argument. The case is reported 7 El. & B. 725. In 1857 application was made by one R. Gordon, to the Attorney General, for a scire facias to repeal the patent; but, after hearing counsel, he refused to grant the writ. In June, 1863, the plaintiff applied for and obtained from the Privy Council an extension of his patent for the term of five years, the application being strenuously opposed by several parties. Various other actions had been brought by the plaintiff against different persons, in all of which the defendants sooner or later submitted. The bill charged that the present defendant was infringing the plaintiff's patent by using an artificial exhaust of the plenum of air from the mill-stone cases, and by carrying away the stive so exhausted to a stive room or chamber, and in other ways. The apparatus used by the defendant, which was complained of as infringing the plaintiff's patent, was in substance as follows: Each pair of stones was inclosed in a case which was left open at top, and at bottom was made wider than the stone it inclosed, and also deeper, so as to leave a space beneath the lower stone. In this space a fan was introduced, which was attached to and revolved with the mill-stone shaft, thereby drawing a current of air up from the meal-spout into the mill-stone case, as in the plaintiff's process, and this current was carried off from the case by a pipe leading to the outer air. The first part of the plaintiff's patent was not alleged to be infringed. The defence as to the second part of the patent, which was the point most in dispute, was, that the plaintiff's patent only applied where an exhaust was used in combination with some artificial blast driven down the eye by a blowing-machine, and that the plaintiff's specification was expressly so limited; that if the plaintiff's patent included a simple exhaust without an artificial blast down the eye, then it was bad, as such an exhaust was not new; and that the defendant's process was not an infringement, as no sort of artificial blast down the eye was used. Various instances of prior user of an exhaust without any blast down the eye other than that caused by the action of the stones were adduced by the defendant's witnesses, including certain French patents which had expired. The defendant further insisted that the plaintiff's own machinery, as used at present by him, was not in accordance with his specification, as no artificial blast was used. With regard to part No. 3, the defendant denied using a stive chamber, or any filtering apparatus. It appears by the evidence in Bovill v. Keyworth that the defendants there used an exhaust with an artificial only succeed now by including that in his blast down the eye. Mr. Grove, Mr. Baggallay, Mr. Hindmarch, Mr. Druce and Mr. T. Aston, for the plaintiff, relied upon Bovill v. Keyworth, as establishing the validity of the patent in all respects. They urged the hardship to which the plaintiff would be subjected if, after having fought and succeeded again and again, he had to establish his patent afresh against each new defendant. They relied upon Davenport v. Goldberg, 2 Hem. & M. 282. They also cited Lister v. Leather, 8 El. & B. 1004; s.c. s.c. 27 Law J. Rep. (N.S.) Q.B. 154. The Attorney General, Mr. Selwyn, Mr. Little, Mr. Watkin Williams and Mr. Fullarton, for the defendant, were about to cross-examine the plaintiff as to the novelty of his invention, but desisted, on his Lordship expressing an opinion that the novelty of the invention, as well as the sufficiency of the specification, was established by Bovill v. Keyworth.-They argued that the defendant could not be concluded by a previous action to which he was not a party, and that the plaintiff would gain a monstrous advantage if one verdict at law were to establish a patent against all other persons. A patentee would then pick out a weak defendant, unable to try the question properly, get a verdict against him, and conclude all the rest of the world thereby. Patentees would first establish their patent by construing the specification in its most restricted sense, and, having established its validity on that footing, would afterwards, in suits in equity for infringement, contend for an extent of application which would have been fatal to them if the validity of the patent could have been argued at the same time. The plaintiff in the present case, with regard to the second part of his patent, could only make the defendant liable by shewing that his patent included an exhaust without a blast, while, in Bovill v. Keyworth, its validity was decided expressly on the ground that it was only for an exhaust in combination with a blast; the plaintiff could NEW SERIES, 35.—CHANC. patent for the exclusion of which it was previously held valid. They cited Bridson v. Benecke, 12 Beav. 3. Foxwell v. Webster, 9 Law Times, 528. As to the principles on which prolongations are granted by the Privy CouncilWoodcroft's Patent, 10 Jur. 363; and as to the proceedings in this particular case 1 Moo. P.C.C. (N.s.) 348. Mr. Grove, in reply. The MASTER OF THE ROLLS (April 18)— After stating the nature of the case, and that the defendant denied both the validity of the patent and the fact of infringement, and after remarking on the litigation to which the plaintiff had been subjected, and the difficulty of holding an even balance between the hostile claims of inventors and of the public, said :-The law attaches superior rights to a patentee who has established the validity of his patent to those which belong to a patentee who has not done so. The former stands on a different footing, and though the patent may be contested by fresh persons, he will receive protection until the invalidity of it is shewn. The distinction hitherto made by Courts of equity has been that where the validity of the patent has not been the subject of any legal proceedings the patentee must prove its validity at law before the Court of equity will protect him; but having once established its validity, then the Court of equity will protect him against another person until that person proves its invalidity. Accordingly, the first thing I have to consider in this case is the fact, whether Mr. Bovill has established the validity of his patent in a Court of law. If he has done so, it has been by the case of Bovill v. Keyworth. The defendant contends that this case does not establish the validity of the plaintiff's patent, and that, if it does, it is for an invention which is not infringed by him. The way in which the defendant puts his case may be shortly stated thus: If the patent be such as is established by the case of Bovill v. Key 3 K worth, then the defendant has not infringed it; but if the patent be such as the plaintiff contends that it is, then its validity is not established by the case of Bovill v. Keyworth, and the patent so alleged is in valid, and principally by reason of its want of novelty. In order to estimate the value of this argument, it is necessary to consider what the invention is which is described in the specification, and what the case of Bovill v. Keyworth has decided.-[His Lordship then read the specification as given above.] Now it is argued that this is merely a patent for the combination of these three processes, each of which was old, and that all that Bovill v. Keyworth has done is to determine that the specification correctly describes an invention consisting of the combination of the three, that this combination is new, that in this consists the invention, and that Bovill v. Keyworth does not go beyond this. I have, therefore, in the first instance, to consider whether the case of Bovill v. Keyworth has established the validity of each of these three matters separately, or only in combination with each other. The judgment of the Court of Queen's Bench appears to me to determine the validity of each. Lord Campbell says, in the first part, "The whole of the plaintiff's process, if the combination is new, is certainly the subject of a patent, and so would the part No. 2, if taken separately, for exhausting the air from the cases of millstones, combined with the application of a blast to the grinding surfaces, as they introduce very important improvements in manufacturing wheat and other grain into meal and flour." Now, that appears to me to point out that the No. 2, taken separately, is also described as an invention by itself, and not in combination. That is made more clear afterwards. He says, "If the specification does not point out the mode in which this is done, it would be invalid. But we are of opinion that the specification, on the face of it, cannot (as contended) be pronounced, in point of law, to be bad in this respect, and we are of opinion that the evidence adduced at the trial shews it to be quite sufficient." Again, "The exhaust produced by the pipe and fan is to be proportioned to the plenum caused by the blast, taking care not to produce the inconvenient current of air, against which a cau tion is given. How can a Judge take upon himself to say that this may not be enough to enable a workman of competent skill to construct the machinery?" In a further place he says, "We do not think it necessary to try to reconcile the different parts of the specification (which are somewhat conflicting), or to give any positive opinion upon this question; for supposing the patent to be for a combination consisting of several parts for one process, we are of opinion that the defendants are liable in this action for having used a material part of the process which was new, for the same purpose as that mentioned in the specification, although they did not at the same time use all the parts of the process as specified." Now I am of opinion that that establishes the separate parts of the specification. Great stress was laid in the argument upon these words, "And this part of my invention relates only to sucking away the plenum of dusty air forced through the stones, and not to employing a sufficient exhausting power to induce a current of air between the mill-stones without a blast, this having been practised as above mentioned." But I am of opinion that the application of the exhaust to drawing away the plenum is a material invention of the plaintiff by itself, although the combination of it with the other parts of the invention may be properly and validly claimed as another part of the plaintiff's invention; and this double fact appears to me to be established by the passages in the judgment to which I have referred. There is also this preliminary obstacle in the way of the defendants on the question of the validity of the patent, namely, that the specification of the plaintiff is a written document, of which the construction must be the same in a Court of law as in a Court of equity; and the Court of Queen's Bench has determined that this patent is valid, that is, that the invention was new, that it was useful, and that it is sufficiently described in the specification. The objections urged to me were urged at law, and were present to the mind of Lord Campbell when he delivered his judgment, and the words I have read appear to me distinctly to point to the validity of the patent, not merely in respect of the combination of the matters there mentioned, but also of the validity of the separate parts which are distinctly claimed as inventions by the plaintiff in his specification, assuming those separate parts to be new. I am of opinion therefore that the sucking away of the plenum of dusty air forced through the stones is a separate, distinct part of the invention of the plaintiff claimed by his specification (this is No. 2, in fact) and that the Court of Queen's Bench has determined that this is valid. I admit that this decision would not be conclusive at law in a fresh case, nor would it be binding on me if evidence were now produced which was not before the Court of Queen's Bench; but on this point I do not find that any evidence has been laid before me which was not before the Court of Queen's Bench, with the exception of the French patents, but to those I give little weight. I think they all differ essentially from the inventions of the plaintiff as to the mode of drawing away the dusty air from the plenum; they do not appear ever to have been successful Indeed, the fact that the defendant had not used them, and that no one uses them, and that they have all expired, is a proof that they are not the same as that of the plaintiff, which is confessedly a process of great value. I am further of opinion that the decision of the Court of Queen's Bench also establishes the validity of the plaintiff's patent as regards the third invention, namely, the use of the stive-room, and that this is effected in combination with the exhaustion of the air from the mill-stone cases. It does not appear to me that the forcing the air into the mill-stone case from above is a necessary part of this invention. The invention, as described in the specification, and as established in the Court of Queen's Bench, consists, I think, in the employment of a sufficient power to suck away the dusty air in the mill-stone cases and the discharging it through a porous fabric, by which the fine flour is retained and the air is allowed to escape. It is true that the air which is drawn away from the mill-stone case must find its admission into the mill-stone case from some separate entrance; but the invention now before me, as I understand it, consists in exhausting the dusty air in that case in such a manner as to draw it all off without employing such a force as to draw with it the meal, and to transmit the air so drawn off through a chamber formed wholly or in part of a porous fabric, which will detain the dusty particles of flour and allow the air to escape.-[His Lordship then referred to the French patents, and said that as he thought them quite distinct from that of the plaintiff, it would be unnecessary to go through them in detail, after which he continued:]-I am of opinion that the validity of the patent as now claimed by the plaintiff is established by the decision in Bovill v. Keyworth. I have next to consider what the consequences are which flow from this, both as regards the plaintiff and the defendant. The consequences as regards the defendant are nothing, if he has not infringed the plaintiff's patent. Therefore the next thing to be determined is, whether the evidence before me is sufficient to prove that the defendant has infringed the plaintiff's patent. The burden of proving this lies on the plaintiff. The evidence is to this effect that the defendant has employed a fan placed on the spindle of the mill-stones, working in the case below the lower millstone, and extending a little beyond the periphery of the mill-stone. This fan is driven by the ordinary power of the mill. The effect of the action of this fan is, that the dusty air of the plenum is driven or blown out into an escape-pipe, and so on through another pipe or chamber into the open air. Some blast is produced by the centrifugal action of the mill-stones, but the revolution of the fan increases the ordinary centrifugal blast arising from the action of the mill-stones to an extent sufficient to drive the dusty air from the plenum into the escape-pipe, without sending out the meal, which descends in the regular manner down the meal-spout. I attended carefully to the evidence given on this subject in court, in conjunction with the models then produced, and I listened attentively to the arguments of counsel on this point, and certainly no case I have ever heard was better argued. I have since read over again the evidence and considered the whole matter; and my opinion at the close of the argument, since fortified by my examination and reconsideration of the subject, is, that the process used by the defendant, which is Blake & Lee's patent, is substantially, that is, in essential points, the same as the plaintiff's patent; the only difference appears to me to be that the plaintiff exhausts the plenum or removes the hot dusty air from the mill-stone case by means of a sucking process applied externally, which draws the air from the plenum through a shaft prepared for the reception of it, and that the defendant exhausts his plenum or removes the hot dusty air from the millstone case by means of a blowing process, which drives the air from the plenum into a shaft prepared for the reception of it. I do not find that before the plaintiff's invention, in 1849, any process had been discovered by which the hot dusty air could be exhausted from the plenum, carrying with it the stive only; and carrying it, not into the body of the mill, but into a separate shaft, where the stive could be collected and utilized. This is done in both the plaintiff's process and in that used by the defendant. The plaintiff sucks the air out; the defendant blows it out-in both instances it is done by a fan. In every case where a fan is driven, it must suck the air from one place, and blow the air into another place. It is wholly immaterial, as it appears to me, for this purpose, whether the air that is expelled from the mill-stone case is drawn through the eye of the millstone case, or whether it is drawn up through the meal-spout, or whether it is introduced through pipes constructed specially for the purpose of admitting the air. The invention consists in producing a blast exactly so regulated as to exhaust the hot dusty air from the mill-stone case, and drive it with the stive only into a shaft where it may be utilized. This appears to me to be done in both cases by the plaintiff and by the defendant; and as soon as the Court arrives at the conclusion that the invention of the plaintiff is not confined to the combination of the methods described in his specification, but that it extends to this withdrawal, whether by expulsion or by exhaustion, as a separate and distinct invention, then it seems to me that the defendant has made use of the invention of the plaintiff, and that he has in all essential particulars adopted the same process. His Lordship then said, with regard to the remaining part of the plaintiff's the plaintiff's invention, viz. the stive-chamber, that he was satisfied on the evidence that the defendant's process was an adaptation, but an imperfect adaptation, of the plaintiff's process. After which, having remarked that though he had not intended going into the validity of the patent, yet he had done so to the extent of the materials before him, and that, having done so, he thought it right to say he concurred in the decision in Bovill v. Keyworth, he continued—I have, therefore, arrived, first, at the conclusion that the validity of the plaintiff's patent, as now claimed by him, has been established at law, and also that the defendant has infringed that patent. There remains then, further, to be considered, as I have already observed, what are the consequences which flow from these conclusions as regards the plaintiff and as regards the defendant? In the first place, as regards the plaintiff, I am of opinion that he is entitled to a decree for an injunction; but, on the other hand, as regards the defendant, I am of opinion that I cannot properly compel him to submit to the decision of the Court of Queen's Bench, in a suit to which he was no party, or to acquiesce in any opinion I may have formed. Many cases are on record where, after the plaintiff has established the validity of his patent in one case, it has been decided to be invalid in a second. Bridson v. Benecke, Hill v. Thompson, Croskell v. Tuxford establish that the defendant is not to be concluded by a trial at law to which he is no party, and that he is not to be driven to contest the validity of a patent by a scire facias. It is true that the case of Davenport v. Goldberg seems to point the other way, and it is also to be borne in mind that the law was established on this point at a time when the act of parliament had not passed which compelled the Court of equity itself to decide any question of common law which might come before it without the assistance of any tribunal, as to which, however, it is proper to observe, that this is not so much a question of law as it is a question of fact. I cannot also but remember that, although I have considered the validity of the patent of the plaintiff, it is only so far as regards the effect of the decision in Bovill v. Keyworth and the sufficiency of the specification, |