knowledge of the time, and as the questions of construction and validity frequently are only raised as part of the defendant's case, it is found in practice that the question of interpretation cannot be severed entirely from those of novelty and infringement, as the logic of the case would strictly require. The actual issue frequently depends only on the interpretation and extent of one or two claims out of many. Hence the attention of the Court is necessarily directed to these issues before the actual interpretation of the claims and specification is undertaken; this course avoids unnecessary discussion. But, beyond so narrowing the field of inquiry, one's mind ought not to be influenced by issues of validity or infringement. The modern practice is thus defined by Lord Alverstone, L.C.J., in Presto Gear-case Co. v. Orme, Evans & Co. (18 R. P. C. 23)— "In patent cases I have always felt that there is a line of thought which is most likely to lead you to the right result in the speediest way. The first thing, assuming you understand the alphabet of the science or art, is to understand clearly what was the previous state of knowledge. Having got, either by agreement or deduction from the evidence, a clear view as to what was the previous state of knowledge, you must then construe the specification with reference to that, disregarding issues of novelty or subject-matter which may arise in the particular case, and you then have to consider whether or not the infringement comes within the fair meaning of the claims, not anything else, but the claims read in the light of the previous state of knowledge, and without altering their words unduly in favour of the patentee or the infringer. I will say one word more with regard to the law; that in my judgment, be it a combination claim or be it not, you are only allowed to follow the words of the claim, but you are not to permit mere mechanical equivalents, or mere colourable alterations, to prevent a thing being an infringement, having regard to what the meaning of the claim is." The interpretation of specifications like all other documents is a question of law for the Court.1 But in cases of controversy 5 the 1 See post, pp. 86, 87. * The "state of knowledge" in cases of ambiguity of language or ambit of claim involves the question of novelty, and such has been taken into consideration by the House of Lords on the principle of Benevolent Construction, post, pp. 93, 94. 3 Equivalents are discussed post, pp. 96-99. Bush v. Fox, 5 H. L. Ca. 707; Hills v. Evans (per Lord Westbury, L.C.), 4 De Gex, F. & J. 294, post, p. 223; Simpson v. Holliday, post, p. 245; British Dynamite Co. v. Krebs (per Lord Cairns), 13 R. P. C. 192, post, p. 275. Betts v. Menzies, 31 L. J. Q. B. 239. Court must be informed by evidence of the state of knowledge of the art in question, the meaning of technical terms, &c., at the date of the specification,1 and not including subsequent knowledge.2 Illustration. An alleged anticipating specification was forty-five years earlier than the one the validity of which was in question. Evidence was admissible to show whether the same terms in the two documents at these different periods (1804 and 1849) referred to the same things. Betts v. Menzies, post, p. 217 (per Lord Westbury, L.C.), post, p. 219. Where, however, the matter or language is not of a technical nature, or describes a very simple invention, there is no need of expert evidence, and the whole question is one of law.3 Illustrations. As to whether directions to heat were included in the term "or I accelerate the operation by heating," see Simpson v. Holliday, post, P. 244. In a case in which the invention consisted of a comb to be sewn in ladies' hats, the issue of validity depended on the description in an antecedent specification. Savage v. Harris, 13 R. P. C. 368. The knowledge of the time at the date of the specification includes what persons in the trade actually do-descriptions published in books and other publications under circumstances that lead to the conclusion that persons have become acquainted with their contents.1 Specifications, however, are considered as published in fact as well as in law. 90). Illustration. The question at issue was the validity of Haddan's patent for seriesshunt winding of dynamos. An alleged anticipation was contained in Varley's specification (1876). In construing the latter the knowledge of shunt winding disclosed by Clark's specification (1875) was considered. Although it was unknown to Lord Kelvin at the date of Varley's invention, yet as it was proved to have been 1 Crossley v. Beverley, 1 Webs. 107, 108. 2 Heath v. Unwin, post, p. 200 (followed in Badische Anilin, &c. v. Levinstein, 2 R. P. C. 23-29. Simpson v. Holliday, post, p. 245. Harris v. Rothwell (per Lindley, L.J.), 4 R. P. C. 231. Also Publication, ante, pp. known to Varley, it may have been known to other electricians. King v. Anglo-American Brush Corp., post, p. 340, (per Lord Watson) p. 344. In construing a specification in the light of previous knowledge and publications, due regard must be had to disclaimers. The power to amend specifications by amendment and disclaimer was granted by the Act of 1834 (5 & 6 Will. 4, c. 83, sect. 1); it is now exercised under the Act of 1883, by way of disclaimer, correction, or explanation.1 A specification of which part has been struck out by disclaimer will very often bear a different meaning to what it would have done had it originally been drawn as amended. Illustrations of the effect of disclaimers will be more conveniently considered below in connection with claims and equivalents. A disclaimer was never intended to enable an inventor to make a bad patent good by altering it to something requiring research and experiment." The "nature of the invention," as described and claimed in a specification, is in all cases a question of construction for the Court, assisted by evidence as to the knowledge of the time and surrounding circumstances; it must be ascertained from the whole specification (including drawings1), all the facts of the discovery being first ascertained. An invention consists in the application of principles and not merely in their enunciation (ante, p. 9). In all cases it is the real merit, and not the mere description, that must be looked to." Illustrations. The absence of any mention of a previous use in the specification caused the claim to be read to include more than the actual invention in Hill v. Thompson, post, p. 185. The real merit in Lyon's disinfector lay in the strength of the door of the machine. This was not pointed out in the letterpress, but was apparent from the drawings. See Lyon v. Goddard, post, p. 362. The manner of the application in the way described of hydrated ferric oxide to the manufacture of coal gas was held to be an invention in Hills v. London Gas Light Co., post, p. 208, 211. 1 Post, Ch. IX., P. 160. 2 See Ralston v. Smith, post, p. 229. Per Lord Cairns in British Dynamite Co. v. Krebs, 13 R. P. C. 192. Poupard v. Fardell, 18 W. R. 129. 5 Siddell v. Vickers, post, p. 329, Í. 23; Newton v. Grand Junction Ry. Co., 5 Ex. 334 ; Lister v. Leather, 8 E. & B. 1022. • Per Lindley, L.J., in Benno Jaffé, &c. v. J. Richardson & Co., post, p. 357. Admitting mixed gas and air to the cylinder of Otto's gas engine, and compressing the charge as described and claimed in the specification, were applications of principles. See Otto v. Linford, post, p. 283. For a good example of the importance and application of this principle of interpretation, see Gormully, &c., Co. v. North British Rubber Co., post, p. 414. See Gaulard & Gibbs' Patent for a general illustration, post, p. 332 1. See Benno Jaffe, &c. v. Richardson, post, p. 356. The specification will not be read in a narrow and technical manner, but in a practical and commercial sense;1 the sense in which those to whom it is addressed (ante, p. 73) would read it. Illustrations. In a specification for the manufacture of aniline dyes the term "dry arsenic" was interpreted as the arsenic of commerce physically dry, and not the anhydrous acid, which was not then an article of commerce. Simpson v. Holliday, post, p. 245. In a specification dealing with the manufacture of glow lamps the term "carbon gas" in the claim was read in connection with the whole specification in which "hydro-carbon gas" was mentioned, and it was held that "carbon gas" did not include CO or CO2, but substances containing carbon and hydrogen, even along with other elements; although technically the term "hydro-carbon" referred to compounds of C and H only. Edison & Swan v. Woodhouse, 4 R. P. C. at p. 107, and post, p. 299. In a specification for smokeless powder the term "soluble nitrocellulose" meant that known commercially as soluble in an ether-alcohol mixture, and excluded the "insoluble nitrocellulose" or guncotton. Nobel v. Anderson, post, p. 366. Proportions. Questions frequently arise in connection with the mention of, or absence of allusion to, precise proportions of ingredients. In this respect there can be no general rule. On reading the specification as a whole, assisted by evidence as to the knowledge of the art, in some cases the essence of the invention may consist in the discovery of the properties arising from the combination of substances in certain proportions; or the proportions may be important only as regards directions to workmen, or may depend altogether on the use to which the invention is to be put, e.g. shades of colour in dyeing. 1 Crossley v. Beverley, 3 C. & P. 515. Illustrations. Proportions of metals used for making capsules were held to be not essential, but only relative, as showing how to obtain the best results in Neilson v. Betts, L. R. 5 H. L. 21, post, p. 220. The essence of the Nitro-glycerine and gun-cotton were mixed "in, or about in" certain proportions to make a smokeless powder. invention lay in keeping within those limits. &c. v. Anderson, post, p. 418. Suitable limits of proportions were given for ingredients used in mantles for incandescent gas lighting. It was subsequently discovered that proportions far outside those given would suit. The claim did not include the later discovery. See Welsbach, &c. v. Daylight Inc. Mantle Co., post, p. 391. See Heath v. Unwin, note 2, post, p. 201. Claims. Questions arising out of the construction of claims frequently present some special features. The claim must be construed as part of the whole document1 (including the title). The description of the invention given in the specification should first be read, and then the claims to see how much of the invention described is claimed. This is the rule whether the words "substantially as described❞ are in the claim or not. A claim for every form of applying a principle would amount to a claim to the principle itself, hence it can only extend to include the applications of the principle - that is, the manufacture or invention itself—in one or more of the forms described. So, too, the claim must be read in the light of the function the thing described was to perform.5 Illustrations. One claim for the Wheatstone telegraph was for improvements in communicating angular motions to magnetic needles "by means of currents transmitted through metallic circuits." Construing the claim in connection with the whole invention, it was held to include 1 Newton v. Grand Junction Ry. Co., 5 Ex. 334; Lister v. Leather, 8 E. & B. 1022. 2 Oxley v. Holden (per Erle, C.J.), 8 C. B. N. S. 707. Arnold v. Bradbury, L. R. 6 Ch. Ap. 706, 712; Edison, Bell, &c. v. Smith, 11 R. P. C. 395; Tubes, &c. v. Perfecta Seamless, &c., 17 R. P. C. 588. I ♦ Neilson v. Harford (per Alderson, B.), 1 Webs. 355; Nobel v. Anderson, 11 R. P. C. 525, 527, 532; Ticket Punch Reg. Co. v. Colley's Patents, 12 R. P. C. 185. 5 Fawcett v. Homan, 13 R. P. C. 410. |