the process, although the resulting substance was no better. Wood v. Zimmer, 1 Webs. 82. A patent was granted for trusses. The omission to state that tallow should be used (which was material) to facilitate the tempering was held to invalidate the patent (Liardet v. Johnson, 1 Webs. 53 as explained in Turner v. Winter, 1 Webs. 82, and Morgan v. Seaward, 1 Webs. 175), it being understood that the specification was addressed to "persons of reasonably competent skill in such matters" (Harmar v. Playne, Dav. P. C. 318). For an illustration of ambiguity and false suggestion invalidating a patent, see Turner v. Winter, post, p. 181. A patent was granted for machinery for drying paper. The specification stated that the invention consisted "in conducting the paper, by means of cloth or cloths, against the heated cylinder, which cloth may be made of any suitable material, but I prefer it to be made of linen warp and woollen weft." It was proved that the inventor had tried linen cloth and woollen cloth, and that both had failed. Held, that the patent was void, as the patentee should have given the public the benefit of this knowledge. Crompton v. Ibbotson, Dan. & Ll. 33. A patent was for improvements in copper and other plate printing. In the specification the directions were to use the "finest and purest chemical white lead." There was no such substance known in the trade. Ordinary white lead would not do. The only material that would suit was a pure kind of white lead imported from abroad and sold in one particular shop in London. Held that the patent was void. Sturtz v. De La Rue, 5 Russ. 322 (approved in Coles v. Baylis, 3 R. P. C. 180). A patent was granted for certain "improved arrangements for raising ships' anchors and other purposes." The supposed invention consisted in constructing a windlass with a V-shaped groove, scalloped with shell-like indentations to grip the chain-cable. It was proved that a windlass for a chain-cable of a given size was not new, but none was known capable of holding chain-cables of different sizes. The specification did not assert more than that the windlass would grip more than one size of cable. It was doubtful that the words of the specification could mean that the windlass would grip cables of different sizes. Held, that the patent was invalid, for the specification, being equivocal, was insufficient. Hastings v. Brown, 1 E. & B. 453. stone. The patent in question was for an improved manufacture of artificial It consisted of treating certain materials with water (deprived of air) under high pressure. The specification alleged that previous processes failed because of cracks produced in the stone by the admission of air into the moulds, that it was impossible to get a higher temperature than 281° to 292° F., which was insufficient to produce reliable stone. These difficulties the patentee alleged he overcame by working at a much higher temperature, 400° F. It was proved that the stone could be produced of quite as good a quality by working at 240° F., and that working at the higher temperature was commercially disadvantageous, being more expensive. Held that the patent was invalid for false suggestion to the Crown. Owen's Patent, 17 R. P. C. 78. See also Osmonds v. Balmoral Cycle Co., ante, p. 60. Patent upheld, though misleading. The patent was for improvements in shearing-machines for cloth. A complicated machine was described with diagrams. Before the date of the patent the wool had to be raised by means of a brush. In the specification the brush was described incidentally: "A narrow strip of plush is fixed on the surface of A" (the top cylinder) "parallel with the wire B" (a helix round A) “to answer the purpose of a brush for raising up the wool which is to be shorn off the cloth," &c. ; but it was not mentioned as being essential. It was claimed in a separate claim in the following terms: “Third, the application of a proper substance, fixed on or in the cylinder A, to brush the surface of the cloth to be shorn." The patentee subsequently found that it was unnecessary. No machine was ever made with it on. Held that the patent was valid, the patentee having acted in good faith. Lewis v. Marling, 1 Webs. 490 (followed in Poupard v. Fardell, 18 W. R. 129). Illustrations of the latter part of the first rule relating to what additions may be included as "fair developments" are given, ante, pp. 65-69. Sufficiency of Practical Directions. The illustrations above given to illustrate the necessity of an honest disclosure include several which also illustrate the necessity of a sufficient disclosure. There are a large number of cases in which the honesty of the patentee is not in question, but which turned on the sufficiency of the directions. The following cases illustrate the question of sufficiency of disclosure within the meaning of the second of the above rules. There is no obligation on the patentee to go so far as to point out and warn against all the errors a workman might make. Inaccurate use of terms, due to errors in translation or want 1 As the brush could not be used without using the machine, the claim was a "subsidiary one, as to which see ante, pp. 58, 63. 2 Edison & Swan v. Holland (per Cotton, L.J.), 6 R. P. C. 282, 1. 16. of knowledge of English, will not render a patent invalid so long as the meaning be clear. If a specification discloses the presence of foreign matter in a substance, it must show that it is not injurious or may be easily removed.1 Equivalents need not be mentioned if well known to those skilled persons to whom the specification is addressed, but if the equivalents be not previously known as such they should be mentioned, otherwise they will not be included in the claim.2 Errors, unless they are purposely inserted, will not vitiate a patent if the ordinary skilled workman can correct them at once without having to make experiments and further inquiry, for such errors would not mislead. But if intentionally inserted there is not an honest disclosure. Illustrations of Insufficiency in Directions. The specification for a method of sharpening "knives, razors, scissors, and other cutting instruments" described a contrivance about four inches long, consisting of two parallel cylinders with alternate bosses and recesses. These were placed so that the distance between the axes of the cylinders was less than double the radius of the bosses, hence these, on each cylinder, fitted into the recesses of the other. The sharpening process was carried out by drawing the edge of the cutting instrument along a V, formed by the intersection of the circumferences of the bosses. For scissors it was necessary to have one set of bosses smooth, or else both of Turkey This information was not given in the specification. stone. Felton v. Greaves, 3 C. & P. 611. A patent for a lamp was held invalid because neither letterpress nor drawings showed holes to admit air on one side of the wick; these were necessary. Hinks v. The Safety Lighting Co., post, P. 254. As to absence of directions to apply a certain solution for preserving meat, see Bailey v. Roberton, post, p. 270. A patent was taken out for improvements in the manufacture of bread and biscuits. Certain proportions and directions were given in the specifications. The patentee, when instructing his workmen, gave them further directions and other proportions of ingredients. A baker, an agent of the patentee, testified that he required such extra directions to enable him to make the bread. Pooley v. Pointon, 2 R. P. C. 171, 172. 1 Derosne v. Fairie, 1 Webs. 161, 162. 2 Heath v. Unwin, 2 Webs. 245. ' Per Lord Westbury, L.C., in Simpson v. Holliday, 12 L. T. N. S. 99, 100. In a patent for, amongst other things, regulating, by means of storage batteries, the pressure in the mains for electric lighting purposes, the apparatus would not work by reason of no directions being given as to switching cells in or out of the circuit. The invention as described was therefore useless. See Lane Fox v. Kensington, &c., post, p. 345. A patentee of a process of manufacture of new dyes claimed a product substantially pure. He gave the fullest directions to the best of his knowledge. The purity of the result was due partly to the use of an iron vessel in the process, the iron of the vessel combining with the acid. If an enamelled vessel were used the process would not produce the pure result claimed. Enamelled vessels were frequently used in such-like operations. The directions were not sufficient. Badische Anilin, &c. v. La Société Chimique des Usines du Rhone, post, p. 405. Alleged Insufficiency disproved. In a specification describing an apparatus for making gas there was no direction to use a condenser which was necessary. But no workman who could make a gas apparatus would leave it out. Nor was there any direction so to do. Crossley v. Beverley, 3 C. & P. 515. In the first patent for a process of photography five operations were described. The first was that of preparing the surface of the plate for the coating with iodine. The second the iodine process. The third, which was to follow immediately on the second, was the exposing of the plate in the camera. At the end of the directions for the first operation the reader was told that it was “indispensable just before the moment of using the plates in the camera... to put once more some acid on the plate." If this were done after the iodine process no image could be produced. At the trial a verdict was directed for the defendant (3 C. B. 97). On appeal, after further examination, it was held that the obscurity was cleared away by consideration of the whole," and that it was "sufficiently plain to be understood by an operator of fair intelligence" that the direction was to be taken as referring to the process of preparing the plate some time in advance, and the third application of the acid was to be just before the iodine process. The patent was upheld. Beard v. Egerton, 8 C. B. 165. Absence of mention of proportions is not material where they depended on the substance chosen, and enough information is given to produce the required result by simple trial. See British Dynamite Co. v. Krebs, post, p. 274. Drawings of slides in a gas-engine were incorrect, and if followed exactly the engine would not work. mation to correct the error. The letterpress contained no infor- required correction. No evidence was produced that any had The use of the term "carbon gas" in a claim where the process shewed that neither CO nor CO, was meant, but only gases containing H, did not mislead any workman. Edison & Swan v. Woodhouse (2nd Action), post, p. 297. Directions for making carbon "filaments' for glow-lamps out of a kneaded combination of tar and lampblack were sufficient because the workman could continue the process till the specified result was obtained. No special directions were given how to avoid diffusion during carbonisation. Edison, &c. v. Holland, post, p. 317. A strained construction will not be put on a specification in order to interpret the directions so as to include substances that will not suit, e.g. by taking the technical instead of commercial meaning of the words; or including extremes of a class of acids. Directions as to how to produce dyes are not insufficient because the precise shades to be produced are not expressed in words. To ascertain the shade actual experiment was necessary. See Badische Anilin, &c. v. Levinstein, post, p. 311. Lord Kelvin's mariners' compass comprised several novelties. As it swung on knife edges some brake was necessary. It was thus described: "Instead of the rubbing surfaces, I use the large bowl, A, attached to the bottom of the glazed case, the bottom forming the roof of the bowl, which is nearly filled with liquid; thus, when there is any motion of the bowl, energy is consumed by the frictional or viscous action of the liquid." It was proved that the effect and utility would be much less if the bowl were fully filled. The claim for this bowl described it as "being filled or partially filled" with oil or other viscous fluid. This claim was only for a minor part of the larger invention. Thomson v. Batty, 6 R. P. C. 87,97. In a specification for a new dye it is sufficient if practical directions be given by which persons can, by trial, find out how to produce any required shade in a given range. The patentee need not enumerate those substances that will not do of a class if he give sufficient directions as to others of the class that will suit. See Leonhardt v. Kallé, post, p. 362. Besides the reason already given for full disclosure by the patentee, namely, to enable the public to use the invention after the monopoly has expired, there is another, viz., that it is contrary to public policy that an inventor should have all the benefit of a monopoly by law, and in addition have the benefit of a trade secret |