that this process was an infringement of the patent, the specification of which claimed the use of carburet of manganese in any process for the conversion of iron into cast steel;' for although the plaintiff only mentioned carburet as a well-known substance which he put into the crucible, his patent was held to cover every mode of operating whereby carburet of manganese, however formed, was made to act upon iron. The result by the two processes was identical. The process used by Smith, the defendant in this action, was similar to that of the five manufacturers. If it was the same as the plaintiff's, he had a good defence; for the process was not new, and the plaintiff's patent was invalid: if it was not the same as the plaintiff's, then there was no infringement.

Where the defendants at the trial of an action for the infringement of a patent for a method of manufacturing penholders proved that they had made penholders according to the method which the plaintiff afterwards patented, and that such penholders had been placed in their warehouse for sale, though no sale was proved, Sir J. Jervis, C. J., the presiding judge, held that the plaintiff's invention was destitute of novelty. (Mullins v. Hart, 3 Car. & K. 297.)

The sale in England of articles made abroad is an anticipation of a subsequently patented invention. (Jensen v. Smith, 2 R. P. C. 249.)

The following later cases on the subject of prior user may be referred to: Croysdale v. Fisher, 1 R. P. C. 17; Brereton v. Richardson, 1 R. P. C. 165; Lister v. Norton, 3 R. P. C. 199; Podmore v. Wright, 5 R. P. C. 380.

It was decided by V. C. Bacon in the case of Rolls v. Isaacs (L. R. 19 Ch. D. 268) that the prior user of an invention in a colony does not affect the validity of a patent subsequently obtained for the same invention in the United Kingdom.

But, in order to break down the patent of the person who was de facto the first to produce a useful article by the

patented process, the fact of anticipation, if that is relied on, must be very clearly made out. (Von Heyden v. Neustadt, 50 L. J. N. s. Ch. 126.)

When previous public user of the invention is relied upon as ground of the invalidity of a patent, it is not necessary to show that such user continued up to the time of the patent being granted. Even if discontinued, the patent will be invalidated. (The Househill Co. v. Neilson, 1 W. P. C. 709, in the House of Lords. And see the remarks of Sir W. P. Wood, V. C., on Jones v. Pearce in Tangye v. Stott, 14 W. R. 386, as well as the case of King, Brown & Co. v. Anglo-American Brush Corporation, 6 R. P. C. 414.) Their lordships, however, in delivering judgment in the first of these cases, expressly left it an open question whether a patent for an invention would or would not stand, if a similar invention had formerly been in use but had ceased to be used long before the date of the patent, and the thing had been completely lost sight of until discovered again and patented.

Secret User, from which the inventor derives a profit, and being not merely a user by way of experiment, will certainly deprive his after-acquired patent of its validity. But there is still the question whether prior secret user by someone other than the patentee is sufficient to vitiate a patent. This point has never been judicially decided in an English court; but we have a dictum of Mr. Justice Erle, uttered in the above case of Heath v. Smith: If one party only,' said that learned judge, 'had used the process, and had brought out the article for profit, and kept the method entirely secret, I am not prepared to say that then the patent would have been valid.' Tennant's case (ante, p. 33) may be referred to, as well as Lord Abinger's remark in Carpenter v. Smith (ante, p. 37) and the note on page 38.

Fraud. By the thirty-fifth section of the Patents Act of 1883 it is enacted that a patent granted to the true and first inventor shall not be invalidated by an application in fraud of him, or by provisional protection obtained thereon,

or by any use or publication of the invention subsequent to that fraudulent application during the period of provisional protection.

Abandoned Experiments of other Persons.-A patent is not invalidated by the fact that persons other than the patentee had previously made experiments in the direction of the invention, if such experiments did not result in the utilization of the discovery. Few patents, indeed, could be sustained if previous experiments, approaching the patented invention, were held to vitiate them. In almost every case experiments of some kind or other have been made in the same track, and many beneficial inventions have been but a step beyond what has before been reached by experiments which seemed fruitless, and were abandoned.

The question whether the evidence amounts to proof of public use, or whether it only proves that abandoned experiments had been made, is frequently of considerable delicacy; since, as it has been remarked from the Bench, a slight difference in the evidence will establish either the one proposition or the other. (Cornish v. Keene, 1. W. P. C. 519.)

In Galloway v. Bleadon (1 W. P. C. 525), Tindal, C. J., said, 'A mere experiment, or a mere course of experiments, for the purpose of producing a result which is not brought to its completion, but begins and ends in uncertain experiments, that is not such an invention as should prevent another person, who is more successful, or pursues with greater industry the chain in the line which has been laid out for him by the preceding inventor, from availing himself of it and having the benefit of it. . . . That there had been many experiments made upon the same line, and almost tending, if not entirely, to the same result, is clear from the testimony you have heard; and that these were experiments known to various persons. But if they rested on experiment only, and had not attained the object for which the patent was taken out, mere experiment, afterwards supposed by the parties to be fruitless, and abandoned because they had not brought it to a complete result, that will not prevent

a more successful competitor who may avail himself, so far as his predecessors have gone, of their discoveries, and add the last link of improvement in bringing it to perfection." See also the observations of the same learned judge in Cornish v. Keene (1 W. P. C. 508).

In Jones v. Pearce (1 W. P. C. 124), an action brought for an infringement of a patent for an improved construction of carriage-wheels, the defendants contended that wheels similar in principle to those for which the patent had been obtained had been invented several years previously by a Mr. Strutt, made under his orders, and used in a cart employed on the public roads for upwards of a year. These wheels were afterwards laid by, the spokes having occasionally got bent. Patteson, J., told the jury that if you are of opinion that Mr. Strutt's wheel was an experiment, and that he found it did not answer, and ceased to use it altogether, and abandoned it as useless, and nobody else followed it up, and that the plaintiff's invention, which came afterwards, was his own invention, and remedied the defects. of Mr. Strutt's wheel, then there is no reason for saying that the plaintiff's patent is not good.'

On the trial of an action for infringing a patent for improvements in cards for carding fibrous substances, which improvements consisted in using caoutchouc as a substitute for leather as an elastic bed in which the teeth were fixed, it was given in evidence, in support of a plea denying the novelty of the invention, that a certain material, called Hancock's patent leather, had been made and sold previously to the patent; and it was suggested, rather than proved, that this material was substantially the same thing as the elastic bed in which the carding teeth were fixed. It appeared that the patent leather had been supplied to certain manufacturing firms, during the space of about a year and a half, several years before the date of the patent, and that it had been used in the construction of cards, but had not been employed for that purpose since that time. 'Supposing,' said Cresswell, J., to the jury that the article (Hancock's patent leather) did embody the principle of the

plaintiff, so as to present to persons using it the properties, qualities, and advantages in principle of that article which the plaintiff makes, the question for you will be, whether that user is not to be considered rather in the nature of an experiment, than of any public use of the article, so as to deprive the plaintiff of the fruit of his discovery in respect of this manufacture.' (Walton v. Bateman, 1 W. P. C. 619.) At the trial of Stead v. Williams (2 W. P. C. 135), Cresswell, J., said to the jury, 'I take it that there is a great difference between the knowledge of an invention as a thing that would answer and was in use, and the knowledge of it as a mere experiment that had been found to be a failure, and thrown aside. If a person has had a scheme in his head and has carried it out, but after a trial has thrown it aside, and the thing is forgotten and gone by, then another person re-introducing it may, within the meaning of the Act, be the inventor and the first user of it, so as to justify a patent.'

In the case of Tangye v. Stott (W. N. 1866, p. 68), it appeared that the plaintiff was the assignee of a patent obtained for improvements in pulley-blocks, and that previous to the patent there had been described in a book a pulley similar in principle to that patented, from which description one Moore had made a pulley. This he had tried a few times and then laid aside. The defendant had also made a pulley from the description in the book. It was held, however, that although the principle had been made known, the facts above mentioned were of the nature of experiments, and that as the patentee was the first to carry the invention. fully into effect his patent was good.

In Hills v. London Gas Light Co. (5 H. & N. 312) it appeared that Mr. Croll had purified many thousand feet of gas by a mode for which Hills subsequently obtained a patent, and this gas was sold. The jury, on the trial of an action brought by Hills for the infringement of his patent, found that this was by way of experiment, and the Court refused to disturb the verdict. In delivering judgment on the defendants' rule for a new trial, the Court said, 'The