details of the two machines (Murray v. Clayton, 7 L. R. Ch. 570).

It may happen that a given invention results from the combined operation of two or more minds, in which case it is necessary that all the inventors should apply for the patent.

Patents have sometimes been disputed on the ground that the patentee owed a material part of the invention to another person; and if this can be made out on satisfactory evidence, it is fatal. It must, however, be taken to be undoubted law, that the suggestions of workmen employed by the inventor to carry out his ideas will have no such effect. An inventor is entitled to something more than the mere manual labour of the persons he employs. If the substantial part and leading idea, the principle of an invention, belong to one person, he may properly call in the assistance of another to work it out and improve it; and after obtaining the benefit of that assistance, he may legally procure a patent for the invention. The observations of Alderson, J., to the jury on trying Minter v. Wells (1 W. P. C. 132) will throw light upon this point. 'Minter [the patentee] and Sutton [a workman employed by Minter] were together about the time the invention took place: which of the two suggested the invention, and which carried it into effect, is a question for you to decide. If Sutton suggested the principle to Minter, then he would be the inventor. If, on the other hand, Minter suggested the principle to Sutton, and Sutton was assisting him, then Minter would be the first and true inventor, and Sutton would be a machine, so to speak, which Minter uses for the purpose of enabling him to carry his original conception into effect. You will judge which is the more probable of the two. Minter makes out his primâ

See the note on p. 51.

facie case; he is the person who takes out the patent. If Sutton has received a compensation, nothing would have been more simple and easy than that he should have taken out the patent, and still Minter might have had the same benefit to-day; and there is no apparent reason why Sutton should not have taken out the patent which Minter has taken out, unless they were both desirous to ruin the invention; for suppose two persons are engaged on an invention of this description, they know perfectly well between themselves who is the real inventor of it, and who is the workman to carry into effect the conception; but they would destroy the value of it to both if they did not take it out in the name of the right person.'

In Bloxam v. Elsee (1 Carp. Rep. 434) an action brought for an infringement of a patent for making paper in large sheets, it was objected that many of the improvements set out in the specification were invented, not by the patentees, but by Mr. Donkin, and without them the invention was useless. Mr. Donkin was called, and proved that he was employed by the patentees to bring the machine to perfection, was paid by them for so doing, and was acting as their servant. It was contended, in reply, that these were the patentees' inventions, and that Mr. Donkin was employed by them to carry their ideas into effect. This view of the case seems to have been that of the judge presiding at the trial, and that of the judges before whom the motion for a nonsuit was argued; for although the patent was declared invalid, it was on other grounds, nothing being said on this point.

In Allen v. Rawson (1 C. B. 551), a case where the validity of a patent for improvements in the manufacture of felted fabrics was contested on the ground that parts of the invention owed their origin to two workmen, it was held that more convenient modes of

carrying out the main principle of an invention and subordinate improvements suggested by persons in the employment of the patentee may be safely adopted by him and embodied in his specification. I take the law to be' (said Mr. Justice Erle, before whom the action for an infringement was tried), 'that if a person has discovered an improved principle, and employs engineers, agents or other persons to assist him in carrying out that principle, and they in the course of experiments arising from that employment make valuable discoveries accessory to the main principle, and tending to carry that out in a better manner, such improvements are the property of the inventor of the original improved principle, and may be embodied in his patent; and if so embodied the patent is not avoided by evidence that the agent or servant made the suggestions of the subordinate improvement of the primary and improved principle.' When a new trial was moved for, on the ground that the judge had misdirected the jury, it was refused. On that occasion Tindal, C. J., said, 'It would be difficult to define how far the suggestions of a workman employed in the construction of a machine are to be considered as distinct inventions by him, so as to avoid a patent incorporating them taken out by his employer. Each case must depend upon its own merits. But when we see that the principle and object of an invention are complete without it, I think it is too much that a suggestion of a workman employed in the course of the experiments, of something calculated more easily to carry into effect the conceptions of the inventor, should render the patent void.'

This is a very different case, however, from that where the patentee has no closer connection with the invention than that of being simply the employer of the inventor. Thus, in Arkwright's case, it appeared that Arkwright, the patentee, had been told of a par

ticular roller, part of the machinery by Kay, and that, perceiving the value of the invention, he took Kay into his service for two years, during which time he employed him to make models, and subsequently claimed the invention as his own, making it the foundation of a patent. Arkwright adopted in the same way a crank invented by Hargrave. In the face of this evidence, Arkwright's claim to be the first and true inventor fell to the ground. (Rex v. Arkwright, Dav. P. C. 61; 1 W. P. C. 64.) Again, in the case of Barker v. Shaw (1 W. P. C. 126 n.), an action for the infringement of a patent for an improvement in making hats, a witness proved that he had made the improvement whilst employed in the patentee's workshop, whereupon the plaintiff was nonsuited.

In these cases it was clear that the patentee was not the first and true inventor, since the source of the invention could be traced elsewhere. Whenever this can be done (with the exceptions previously mentioned 1) the patent is invalid. It is so, as we have seen, although the real inventor should be in the service of the patentee; and, à fortiori, will it be so where there, is still less connection between them. In Tennant's case it was proved that, before the grant of the patent, conversations had taken place between Tennant (the patentee) and a chemist, who had suggested to Tennant the basis of the patented improvement. This piece of evidence, in addition to slight evidence of user, induced the Court to nonsuit the plaintiff. (Dav. P. C. 429.)

PUBLICATION IN PRINTED BOOKS.

It has been repeatedly held that an inventor's claim to novelty is destroyed by showing the previous publication of the invention in some printed book in use in Great Britain. Mr. Justice Buller, in Rex v. Ark

See the note on page 51.

wright (1 W. P. C. 72), said, 'It is admitted that this is not a new discovery; for Emmerson's book was produced, which was printed a third time in the year 1773, and that is precisely the same as this.' 'Although' (said Tindal, C. J., in Cornish v. Keene, 1 W. P. C. 507) it is proved that the invention is a new discovery, so far as the world is concerned, yet if anybody has been able to show that although that was new-that the party who got the patent was not the man whose ingenuity first discovered it, that he had borrowed it from A or B, or taken it from a book printed in England, and which was open to all the world—then it would become an important question whether he was the first and original inventor of it.' In the course of the argument of the case of The Househill Company v. Neilson (1 W. P. C. 673), an appeal from the Court of Session in Scotland to the House of Lords, Lyndhurst, L. C., asked, 'If the machine is published in a book, distinctly and closely described, corresponding with the description in the specification of the patent, though it has never been actually worked, is not that an answer to the patent? It is continually the practice on trials for patents to read out of printed books, without reference to anything that has been done.' And Lord Brougham added, 'It negatives being the true and first inventor. It must not be a foreign book, but published in England' (1 W. P. C. 718).

The law, however, has since been interpreted somewhat differently from what is laid down in this last sentence. If the foreign book containing a description of an invention has been circulated in England (Reg. v. Steiner, Newton's Lond. Jour. vol. xl. p. 71), or even if only four copies of the foreign book are sent over to a bookseller in this country and by him exposed for sale, only one being actually sold to a public library (Lang v. Gisborne, 31 Beav. 133), a patent