to be useless, and an obvious truism to those who understand the subject, unless the sentence is understood to be a direction to keep up the temperature; and when we find that in fact no difficulty is experienced by reason of defective instructions on this point, the Court cannot hold as a matter of law that the specification is not sufficiently explicit. If the defendants had shown that the directions as to temperature were not practically sufficient to enable a competent person to make the patented articles, the case would be very different; but they have not attempted to do this; they rely on the words used, and on the evidence as to temperature already alluded to. This, in our opinion, is not sufficient for their purpose. If the language of a specification is clear enough to guide a competent workman, and enable him to obtain the desired result, we cannot see how a Court can hold the language insufficient in point of law. No doubt it is for the Court and not for a workman to construe the specification; but if a workman says it is a sufficient guide to him, and the Court believes him, the Court must hold that, as regards clearness of description, the specification is in point of law sufficient." In Plimpton v. Malcolmson (a), Sir George Jessel said: "It is plain that the specification of a patent is not addressed to people who are ignorant of the subject-matter. It is addressed to people who know something about it; but there are various kinds of people who know something about it, if it is a mechanical invention, as this is; you have, first of all, scientific mechanicians of the first class, eminent engineers; then you have scientific mechanicians of the second class, managers of great manufactories, great employers of labour, persons who have studied mechanicsnot to the same extent as the first class, the scientific engineers, but still to a great extent-for the purpose of conducting manufactories of complicated and unusual machines, and who therefore must have made the subject a matter of very considerable study; and in this class I should include foremen, being men of superior intelligence, who, like their masters, would be capable of invention, and, like the scientific engineers, would be able to find out what was meant even from slight hints and still more from (a) L. R., 3 Ch. D. 568. imperfect description, and would be able to supplement so as to succeed even from a defective description, and, even more than that, would be able to correct an erroneous description that is what I would say of the two first classes, which I would call the scientific classes. The other class consists of the ordinary workman, using that amount of skill and intelligence which is fairly to be expected from him, not a careless man, but a careful man, though not possessing that great scientific knowledge or power of invention which would enable him by himself unaided to supplement a defective description or correct an erroneous description. Now, as I understand it, to be a good specification it must be intelligible to the third class I have mentioned, and that is the result of the law." This judgment very precisely lays down the law upon the subject of intelligibility generally. The next question, as to what is a sufficient specification, is by far the most important branch of the subject. We have seen that part of the consideration for the grant of letters patent is, that the inventor shall particularly describe and ascertain the nature of his invention, and in what manner it is to be performed; consequently for a specification to be sufficient it must particularly ascertain-(1) What the invention itself is; (2) How the invention is to be carried out. Under the first head the inventor must describe exactly and accurately what he has invented, and if in the course of the description of his invention it should be necessary for him to describe something which is old but which he wishes to use in the process of his invention, he must be careful to say, "This is old and I do not claim it as a part of my invention." There are two reasons why the inventor should be called upon to particularly state what he has invented; one is, that the public may be placed in a position to use the invention so soon as the period of protection has elapsed; and the other is, that the public may be protected by being carefully informed what it is that during the period of protection they are not to use. In Macfarlane v. Price (b), Lord Ellenborough said: "The patentee in his specification ought to inform the person who consults it what is new and what is old; he should (b) 1 Web. P. C. 74. say, my improvement consists in this A person ought to be warned by the specification against the use of the particular invention, but it would exceed the wit of man to discover from what he is warned in a case like this." And the same judge, in Harmar v. Playne (c), maintained the same opinion. In the case of Holmes v. London and North-Western Railway (d), A. obtained a patent for an improved turning-table for railway purposes, and in his specification gave a description of the machinery, of which no part was new except certain suspending rods; the combination, however, was both new and useful. In the specification the patentee claimed as his invention "An improved turning table hereinbefore described, such my invention being, to the best of my knowledge and belief, entirely new." It was held, that no construction of the claim could be put upon it as including a combination of the various parts which were old, but that it must be construed as meaning that the patentee claimed the several parts of the invention as being new, and the combination being the only part which was new, the patent was held void. Where a patent is for a combination of old or new parts, or for an improved arrangement of old mechanism, the specification need not discriminate between the new and old parts of such combination or improved apparatus (e) unless any of those subordinate parts are specifically claimed (f). Since it is the new combination or improvement alone that constitutes the novelty and merit of the invention, but it is necessary for the patentee to particularly ascertain and define what his improvement consists of, or what are the exact parts of his new combination, so that any person of ordinary knowledge of the subject may be able at once, on reading the specification, to perceive the invention and the manner in which it is to be performed. In Foxwell v. Bostock (g), Lord Westbury, L.C., said: "I must therefore lay down the rule, which is consistent with and in (c) Dav. P. C. 311; see also Carpenter v. Smith, 1 Web. P. C. 532; Tetley v. Easton, 2 E. & B. 968. (d) 22 L. J., C. P. 57. (e) Kaye v. Chubb, 5 P. O. R. 649; Watling v. Stevens, 3 P. O. R. 41; Moore v. Bennett, 1 P. O. R. 129, 143; Kelly v. Heathman, 7 P. O. R. 348. (f) Lister v. Leather, 8 El. & Bl. 1004; Harrison v. Anderston Foundry Co., L. R., 1 App. Cas. 578; Rowcliffe v. Morris, 3 P. O. R. 23. (g) 4 De G. J. & S. 298, 313; see also Rowcliffe v. Morris, 3 P. O. R. 23. reality a mere sequence from the decided cases, that in a patent for an improved arrangement or new combination of machinery, the specification must describe the improvement and define the novelty otherwise, and in a more specific form than by the general description of the entire machine; it must, to use a logical phrase, assign the differentia of the new combination." Sir W. M. James, V.C., while commenting upon this case in his judgment in Parkes v. Stevens (h), said: "It is obvious that a patentee does not comply, as he ought to do, with the condition of his grant if the improvement is only to be found, like a piece of gold, mixed up with a great quantity of alloy." The degree of sufficiency which is required by the law is very aptly and accurately put by Eyre, C.J., in Boulton v. Bull (i) : "Suppose a newly-invented chemical process and the specification should direct that some particular chemical substance should be poured upon gold in a state of fusion, it would be necessary that, in order to carry out this operation, the gold should be put in a crucible, and should be melted in that crucible, but it would be hardly necessary to state in the specification the manner in which, or the utensils with which, the operation of putting gold in a state of fusion was to be performed. These are mere incidents, with which every man acquainted with the subject is familiar." In taking this distinction as a guide, however, we must be careful to remember that could it be shown that the chemical process would only be successful when the gold was melted in a particular kind of crucible, or at a particular temperature, that then, unless the description was given of the temperature and of the crucible, the specification would be insufficient. In Turner v. Winter (k), Ashurst, J., said: "It is incumbent on the patentee to 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 is any unnecessary (h) L. R., 8 Eq. 365; see also Harrison v. Anderston Foundry Co., L. R., 1 App. Cas. 574, 578; Moore v. Bennett, P. O. R. 129, 143; Philpot v. Hanbury, 2 P. O. R. 33. (i) 2 H. Bl. 498; see also Badische Anilin und Soda Fabrik v. Levinstein, 4 P. O. R. 469. (k) 1 Web. P. C. 80; see also Gibson v. Brand, 1 Web. P. C. 627. ambiguity affectedly introduced into the specification, or anything which tends to mislead the public, in that case the patent is void." If a patentee suppresses anything, or if he misleads, or if he does not communicate all he knows, his specification is bad. In Crompton v. Ibbotson (1), the specification stated: "My invention consists in conducting paper by means of a cloth against a heated cylinder, which cloth may be of any suitable material, but I prefer it to be made of linen warp and woollen weft." It appeared that the plaintiff had tried several things but was unable to discover anything that would answer the purpose with the exception of the material which he said "he preferred." Lord Tenterden held that the specification was misleading, and therefore bad. Jessel, M.R., in Plimpton v. Malcolmson (m), said: “You must not give people mechanical problems and call them specifications." In R. v. Wheeler (n), Abbott, C.J., said: "A specification which casts upon the public the expense and labour of experiment and trial is undoubtedly bad." But where the ambiguity is of such a character that it would be cleared up by a workman of ordinary ability and information in his trade, such ambiguity will not avoid the patent (o). Lindley, L.J., in Edison v. in the Court of Appeal, said: (7) D. & L. 33; see also Savory v. Price, 1 Web. P. C. 83; Lewis v. Marlng, 1 Web. P. C. 493; Hastings v. Brown, 22 L. J., Q. B. 161; Wegmann v. Corcoran, L. R., 13 Ch. D. 65. (m) L. R., 3 Ch. D. 576. (n) 2 B. & Ald. 354; see also Stevens v. Keating, 2 Exch. R. 778; British Dynamite Co. v. Krebs, Good. P. C. 90; Wegmann v. Corcoran, L. R., 13 Ch. D. 65. (0) Morgan v. Seaward, 1 Web. P. C. 176; British Dynamite Co. v. Krebs, Good. P. C. 93; Edison v. Woodhouse, 4 P. O. R. 107, 108; Badische Anilin Holland (p), in his judgment "I feel the great difficulty of Levinstein, 4 und Soda Fabrik v. (p) 6 P. O. R. 282; see also Macnamara v. Hulse, 2 Web. P. C. 128, n. ; Otto v. Linford, 46 L. T., N. S. 35; Simpson v. Holliday, L. R., 1 H. L. 315; Plimpton v. Malcolmson, L. R., 3 Ch. D. 531. |