on a circuit of constant potential in cases in which current is to be measured; and the armature must be of any ordinary known form and (when the current to be measured passes round the field magnets) to be of constant magnetic power; (2) a magnetic brake whose field is powerful and constant; (3) reduction of axial friction by friction-wheels or hardened points; (4) reduction or balancing of commutator friction by mercury contacts or compound winding; and (5) large forces in motor and brake to swamp residual friction. It was alleged that the defendants' meter, when used on a circuit of constant potential, possessed the above elements, g. the motor was of an "ordinary form now in use (ante, p. 467, l. 28); the separate brake was an alternative (ante, p. 468, l. 1); the starting-coil was the compound winding mentioned ante, p. 469, l. 9 and p. 474, L. 28; the current in the shunt-coil being constant produced a constant field; the arrangement was the alternative mentioned ante, p. 474, l. 31, and that when used on a circuit of constant and known potential it measured current. The defendants maintained that their meter was the application of known principles, and was so constructed that its parts did not perform the same functions as those of the plaintiffs' combination, i.e. it would work with alternating currents, as to which, if the plaintiffs' claim included such matters, the specification was insufficient in directions; that the third claim was for the particular form of magnet described and illustrated, but if wide enough to include defendants' magnets would be invalid. At the trial the learned judge found that the meters performed different functions, the object aimed at and attained by the defendants' being more extensive and useful; that the defendants' brushes were not known equivalents for plaintiffs' cummutator; and that the third claim was a subsidiary claim, and not one for a separate invention. No decision on validity was given (17 R. P. C. 493). The plaintiffs appealed. Held by the Court of Appeal (19 R. P. C. 78) that the meters were different combinations, and that the third claim was limited to compound or built-up magnets. Romer, L.J., on the third claim, in delivering the judgment of the Court pointed out that the preferred ratio would have included old magnets, and continued (p. 92):-"If he was not describing his pole-pieces as an adjunct to his arrangement' of magnets, but was contemplating a claim apart from that arrangement, he was in a position of considerable difficulty, having regard to public knowledge at the date of his patent, in reference to the use of permanent magnets with a disc to form a brake in electricity meters. For in this case he would not be claiming the use of some new combination or arrangement of magnets, or some new magnet invented by him, but would be claiming the use of every known magnet which happened to have poles with what he calls 'large' surfaces, and which form between them what he calls a 'narrow' slit, merely because he had discovered they possessed valuable qualities with reference to a use which might well be held known. It appears to us that it would not be fair as against him to hold he intended to make such a large claim, which might have made it invalid, unless he had clearly indicated such an intention. In our opinion he has not indicated such an intention." The plaintiffs appealed to the House of Lords. The House of Lords upheld the decision of the Court of Appeal. Lord Davey referred to the specification in detail in connection with the first claim, and pointed out that there was only one form of meter described fully therein. "It would of course be wrong to confine the patentee to the exact form of his combination which he has so described and illustrated. I also think that he is entitled to the merit of having first given to the world a practical electricity meter made on the principle of combining the use of an electric brake, operating by means of Faucault currents, with an electro-motor, and to have regard paid to that circumstance in construing his patent. But, on the other hand, it would be equally wrong, and, indeed, would be fatal to the validity of the patent, to allow the patentee such latitude in the construction of his patent and variation in its details as would entitle him to claim every form of electricity meter in which an electro-motor is combined with an electric brake of the kind described, or that combination coupled with a device of any kind for reducing friction, unless he can claim to have himself discovered the principle of such a machine." The law was correctly laid down by Baron Alderson in Jupe v. Pratt (1 Webs. 146). His lordship continued by commenting on the prior publications and by pointing out how the patentee in his spécification allowed of variations in the details. "The elements of the combination (which appear to me to admit of no variation) appear to me to be the following: (1) that the meter is a current meter, i.e., one for measuring only the quantity or ampère hours of the current without regard to any variation in the potential or voltage; (2) that the magnetic field of the motor must be constant; and (3) the use of the patentee's mercury contacts or commutators 'where practicable.' . . . It appears to me that the patentee thus defines the type of machine which he intends to claim as his invention with considerable latitude in detail." As to the argument that the defendant's meter as used performed the same functions as the plaintiff's and was therefore an infringement, his lordship said: "But the question is whether the machine which is said to infringe contains the elements which the patentee considered were an essential part of his combination for the purpose for which it was designed. And it can make no difference in this respect whether the manufacturer or person using the machine is sued. . . . It happens under these conditions that energy is proportional to current because one factor is constant; but to my mind the differences of function still exist. . . . Your lordships are not asked to say whether the respondent's machine is a useful one for the purpose for which it is designed, but whether it is a machine of the same type as the appellant's." 1 His lordship reviewed the specification and evidence relating to the magnets and pole-pieces, finding that the only permanent magnets that 1 As to the distinction between a manufacture (here the meter) and the use to which it is put, see ante, pp. 11-13. As to testing identity of inventions by function, see ante, pp 30, 33, 39. were suggested in the specification were an alternative to the saturated electro-magnets, and were built up with large pole-pieces attached. "But, my lords, I adopt the language of Lord Cranworth1 in Ralston v. Smith, and say that it is not every useful discovery which will constitute a patentable invention, and that to tell a man who has been in the habit of using magnets of various forms for various purposes that one particular form has a useful property which was unknown to him before, is not in any sense to invent a 'new manufacture.'" The third claim "can only (as I think) be supported as pointing out what the patentee considered one of the merits and advantages of a subordinate element in one of the forms of the general combination claimed in the first claim, and as applicable only to the meter invented by the patentee. On the construction of the third claim I think also that it is confined to the use of the magnet in connection with the armature of the motor." His lordship contrasted it with the seventh claim (ante, p. 476) in which the patentee "claims his method of combining the disc armature with the disc constituting the brake," and pointed out that the words inserted by amendment in the third claim (ante, p. 475) were no doubt deliberately chosen, and therefore should not be construed in a wider sense than they naturally bear. The Lord Chancellor and other members of the House fully concurred in Lord Davey's judgment. 1 See ante, p. 230. THE PATENTS ACTS, 1883-1902 (in so far as they relate to the THE PATENTS RULES, 1903.. THE LAW OFFICERS' RULES ADMIRALTY AND WAR OFFICE CIRCULARS PAGE 485 571 573 576 THE INTERNATIONAL CONVENTION .. INSTRUCTIONS TO APPLICANTS (issued by the Patent Office) 588 607 THE PATENTS, DESIGNS, AND TRADE MARKS (46 & 47 VICT. C. 57.) An Act to amend and consolidate the Law relating to Patents A.D. 1883. 1. This Act may be cited as the Patents, Designs, and Trade Marks Act, 1883. 2. This Act is divided into parts, as follows: PART I.—PRELIMINARY. PART II.-PATENTS. PART III.-DESIGNS. PART I. PRELIMINARY. Short title. Division of Act into parts. PART IV. TRADE MARKS. PART V.-GENERAL. 3. This Act, except where it is otherwise expressed, shall commence from and immediately after the 31st day of December, 1883. Commencement of Act. |