the public, all this was held by Jessel, M. R., and afterwards by the Court of Appeal, not to prove a publication sufficient to invalidate the patent. (Plimpton v.

Spiller, L. R. 6 Ch. D. 412.)

It may be inferred from some of the preceding cases, that when the validity of a patent is contested on the ground of the invention having been previously in public use, or communicated to the world by a book, it is not necessary to show that the patentee derived his knowledge of the invention from such user, or book. And it was expressly decided, in Stead v. Williams (2 W. P. C. 142), that if the invention has been already made public by any description contained in a work, whether written or printed, which has been publicly circulated, in such case the patentee is not the first and true inventor within the meaning of the statute, whether he has himself borrowed his invention from such publication or not; because the public cannot be precluded from the right of using such information as they were already possessed of at the time the patent was granted. The application of this principle must depend upon the particular circumstances of each case. The existence of a single copy of the work, though printed, if brought from a depository where it has long been kept in a state of obscurity, would afford a very different inference from the production of an encylopædia or other work in general circulation. The question will be, whether, upon the whole evidence, there has been such a publication as to make the description a part of the public stock of information. (See also Plimpton v. Malcolmson, L. R. 3. Ch. D. 531, and Plimpton v. Spiller, cited above.)

PUBLICATION IN THE SPECIFICATION UNDER A PRIOR PATENT.

The law as regards the publication of the invention in the specification under a prior patent, is precisely

the same as that with reference to a publication in a printed book. The invention has been deprived of its requisite attribute of novelty if it has been described in a previous specification, whether the patent has or has not expired. But if the prior inventor has not shown how the invention is to be practically carried out, and an independent inventor does this and fully explains the mode in which the result is obtainable, his patent will be held good. It will be considered that he has been the first to carry the invention to a useful result, although his patent was granted after another one by which a similar object was sought to be effected. In the case of Betts v. Menzies (10 H. L. C. 117), it was held that a general description in a prior specification or in a published book, even if suggesting information or involving some speculative theory pertinent to the invention in question, is not to be considered as anticipating, and therefore avoiding for want of novelty, a subsequent patent involving a practical invention productive of beneficial results, unless it is ascertained that the antecedent publication involves the same amount of practical and useful information. Betts' patent was for the production of a material capable of application to many useful purposes by combining plates of lead and tin by means of pressure. It appeared that as far back as 1804 one Dobbs had patented a process for making a new material by combining lead and tin by pressure, but he did not with any precision define the relative thicknesses of the plates of metal nor the degree of pressure to be applied, whereas Mr. Betts entered minutely into those points. Moreover, it was not shown that the earlier process had ever been carried into practice. Under these circumstances, the House of Lords held that Betts' invention had not been anticipated. See also the observations of Wood, V. C., in the subsequent

case of Betts v. De Vitre (11 L. T. N. s. 445), in which the validity of the same patent was in question.

The antecedent description of an invention which will have the effect of depriving a subsequently patented invention of the attribute of novelty, must (according to Westbury, L. C., in Hills v. Evans, 4 De G. F. & J. 288), "be such that a person of ordinary knowledge of the subject would at once perceive, understand, and be able practically to apply the discovery, without the necessity of making further experiments and gaining further information, before the invention can be made useful. If something remains to be ascertained which is necessary for the useful application of the discovery, that affords sufficient room for another valid patent. The information

as to the alleged invention given by the prior publication must, for the purposes of practical utility, be equal to that given by the subsequent patent. The invention must be shown to have been before made known. Whatever therefore is essential to the invention must be read out of the prior publication. If specific details are necessary for the practical working and real utility of the alleged invention, they must be found substantially in the prior publication. Apparent generality, or a proposition not true to its full extent, will not prejudice a subsequent statement which is limited and accurate, and gives a specific rule of practical application. Upon principle therefore I conclude that the prior knowledge of an invention to avoid a patent must be a knowledge equal to that required to be given by a patent, viz. such a knowledge as will enable the public to perceive the very discovery, and to carry the invention into practical use." And in the above-cited cases of Betts v. Menzies the same learned judge said (10 H. L. C. 152), "Even if there is identity of language in two specifi

cations, and (remembering that those specifications describe external objects) even if the language is verbatim the same, yet if there are terms of art found in the one specification, and also terms of art found in the other specification, it is impossible to predicate of the two with certainty, that they describe the same identical external object, unless you ascertain that the terms of art used in the one have precisely the same signification, and denote the same external objects at the date of the one specification as they do at the date of the other."

Where a provisional specification contained an incomplete description of a piece of mechanism which was omitted from the complete specification, and another patent was afterwards obtained for similar mechanism, the passage in the preceding patent was held not to be a prior publication of the subsequent invention so as to vitiate the second patent, because the description was not sufficient to enable a workman to make the object. (Stoner v. Todd, L. R. 4 Ch. D. 58.)

The hardship of depriving a bonâ fide inventor of the benefit of his patent, by merely showing that some other individual had invented or used the invention before the date of the patent, seemed so great that the Legislature interposed, by the 2nd sect. of the 5th and 6th Will. IV. c. 83, of which we shall speak more fully in the chapter on the Confirmation of Letters Patent.

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CHAPTER IV.

WHO MAY BE A PATENTEE.

THE reader has already been made acquainted with the fact, that the law requires the grantee of letters patent to be the true and first inventor of the thing in respect of which they were obtained; and we have discussed, in preceding pages, the question-Who is to be considered a true and first inventor? The strict letter of the statute has been so far relaxed as to allow persons simply importing an invention from a foreign country into this realm to obtain a patent in respect of it, provided that such an invention is new and useful, which words are to be interpreted in precisely the same way, whether it is imported from abroad, or whether it is discovered within the limits of the British empire. In other words, the administrators of the law always read the word "inventor," in the statute, as embracing an importer. The first decision on this point was in the case of Edgeberry v. Stephens, to be found in the second volume of Salkeld's Reports, p. 447, and is thus quaintly worded: "If the invention be new in England a patent may be granted, though the thing was practised beyond sea before; for the statute speaks of new manufactures within this realm; so that if it be new here, it is within the statute; for the act intended to encourage new devices useful to the kingdom, and whether learned by travel or by study, it is the same thing."

In Carpenter v. Smith (1 W. P. C. 535), Lord Abinger said, "A man has a right to a patent, not only for his own original patent, but he has a right to a