cautious how he deals with it before he applies for a patent. We may add that, although there may have been neither public user of the invention nor publication of it in a printed book or in a specification, yet if the facts justify the inference that a portion of the public had acquired a knowledge of the secret, a patent subsequently granted will be invalid. Thus one of three referees appointed under an Act of Parliament to inspect the works of gas companies in London, having made a discovery as to a process for purifying gas, whilst engaged in the performance of his duties as referee, took out a patent for it after the three referees had drawn up a report, in which the principle of the process was indicated, though before the report was submitted to the Board of Trade. It was held by the House of Lords (Patterson v. The Gas Light and Coke Company, L. R. 3 App. Ca. 239) that the contents of the report had become public property, and that the patent was invalid.

An inventor may, it seems, safely deposit a machine of his invention, for a reasonable time, in a room open to the public, for the purpose of having its properties tested. (Bentley v. Fleming, 1 C. & K. 587.)

Previously to the passing of the Patent Law Amendment Act, 1852, when separate patents for the three kingdoms of England, Scotland, and Ireland were issued to inventors, it was decided by the House of Lords, in the case of Brown v. Annandale (1 W. P. C. 433), affirming the decision of Roebuck v. Stirling (1 W. P. C. 45), that the public use of an invention in England, prior to the date of letters patent in Scotland, rendered such letters patent void, although the invention was new as regards Scotland.

It was decided, however, 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.

EXPERIMENTS.

It is well-settled law, that when the disclosure of the secret took place only during the course of experiments made with the view of testing or improving the invention (such disclosure being unavoidable and not more than was necessary for the purpose), this will not take away the inventor's right to a patent. Nor will the previous experiments of other persons have that effect, if such experiments did not result in the realisation 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.

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.' His lordship, with reference to the case before him, afterwards remarked, "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, it was contended, on behalf of the defendants, that the invention was not new, wheels similar in principle to those for which the patent had been obtained having 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 Strutt's wheel was, in substance, the same wheel as the patentee's, and if it had been used openly in public, so that everybody might see it, and had continued to use the same thing up to the time of taking out the patent,' undoubtedly, then, that would be a ground to say that the plaintiff's invention is not new. But if, on the other hand, you are of opinion that Mr. Strutt's 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

This part of the learned judge's charge cannot be considered law since the decision of the House of Lords in The Househill Co. v. Neilson (ante, p. 83). And see the remarks of Sir W. P. Wood, V. C., on Jones v. Pearce, in Tangye v. Stott (14 W. R. 128).

wheel, then there is no reason for saying that the plaintiff's patent is not good.'

Before applying for a Patent the inventor of a machine entrusted it to a person for the purpose of trying experiments, and it was held that he had not thereby made it public. (Bentley v. Fleming, 1 Car. & K. 578.)

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 alteration in the effect of the evidence will establish either the one proposition or the other, and the only proper mode of deciding it is by leaving it to the jury. (Cornish v. Keene, 1 W. P. C. 519.)

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 advan

tages 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.

Where a series of experiments performed in the presence of others is not only successful, but is actually of pecuniary benefit to the inventor, it will not necessarily be held that he has given the invention to the