of Appeal, 46 L. T. N. s. 35), the question to be considered is whether the prior specification, fairly read by a person conversant with such matters, would give a reasonably clear description of the later invention that is, supposing it to relate to a machine, whether it would give a reasonably clear description of a machine that would effect what the machine of the later inventor effects. (See also Von Heyden v. Neustadt, 50 L. J. N. s. 126.)

'Even if there is identity of language in two specifications' (said Lord Westbury, in Betts v. Menzies, 10 H. L. C. 152), 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.)

By the thirty-fifth section of the Patent 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.

A patent is not rendered invalid by the fact that the invention includes the subject-matter of a patent previously obtained, and not yet expired, if the later patentee takes care to distinguish his invention from that described in the prior patent, and claims only what belongs to him (Crane v. Price, 1 W. P. C. 413; Lister v. Leather, 8 E. & B. 1004). Of course, the second patentee must obtain the first patentee's licence before working his own patent, or he will lay himself open to an action for an infringement as long as the earlier patent remains in force (Cannington v. Nuttall L. R. 5 H. L. 20); and, of course, there must be some amount of new invention in addition to the previous invention, otherwise there is nothing to afford a foundation for a patent.

The existence of a patent for a certain application of a given thing (which thing is not new) will not vitiate a subsequent patent for another application of the same thing, provided that the two applications are perfectly distinct, and that the second application is not in any way comprised in the specification under the first patent. One Vaucher took out a patent for an improvement in packing hydraulic and other machines by means of a lining of soft metal, whereby certain parts of the machines were rendered air-tight and water-tight. It was subsequently discovered by one Newton, that the same material, soft metal, could be usefully employed in diminishing the friction of machinery in rapid motion, and in preventing the generation of heat, by applying it to the surfaces in contact. It was held, in an action for an infringement of Vaucher's patent, that the two applications of soft metal were essentially different, and Newton's invention was not

wanting in novelty. (Newton v. Vaucher, 6 Exch. Rep. 859.)

Under a patent for the purification of gas, Mr. Croll claimed the use of oxides of iron, which expression was held to mean both hydrated and anhydrous oxides of iron. Hills afterwards obtained a patent for the use of anhydrous oxide of iron for the same purpose; but it was said, in an action which he brought for the infringement of his patent, that he had been anticipated by Croll. On his part it was argued that as it was a fact that some oxides would answer the object in view, and some would not, it became a subject for investigation and experiment to ascertain what oxides it would be proper to employ, and that when he had made the discovery he was entitled to a patent in respect of it. The Court of Exchequer held that this discovery might properly be the subject of a patent. (Hills v. London Gas Light Company, 5 H. and N. 312.)

Having discussed the effect on a patent of prior publication of the invention in printed books or specifications, it is now time to ascertain the meaning of the technical phrase

PUBLIC USER.

One of the first cases which the books contain was decided in 1798. Tennant brought an action for an infringement of a patent which he had obtained for a method of using calcareous earths instead of alkaline. substances in bleaching. It was proved, on the one hand, that bleachers were generally ignorant of the patented bleaching liquor until after the date of the patent. On the other hand, it was proved that a certain bleacher had used the same method of preparing bleaching liquor for five or six years previously to the date of the patent; and that the method had been kept secret from all except his two partners, and two servants

employed in preparing the liquor. On this evidence the plaintiff was nonsuited, the previous user being held to render the patent invalid (Dav. P. C. 429; 1 W. P. C. 125).

The evidence given in Lewis v. Marling, to impugn the patentee's claim of novelty, was that several years previously a similar machine was in use at New York, and that a specification had been sent over in 1811 to a person residing at Leeds, who employed two engineers to manufacture a machine from it, which, however, was never finished. The specification was shown to several persons, but the machine was never brought into use. In 1816 a model of a machine for shearing from list to list, by means of a rotatory cutter, was brought over from America, and shown to two or three persons in the manufactory of the importer; but no machine was ever made from it, nor was it publicly known to exist. Moreover, one Coxon, many years previously, had made a machine to shear from list to list, and this was tried by a person called as a witness; but he did not think it answered, and soon discontinued the use of it. Lord Tenterden told the jury that if it could be shown that the patentee had seen the model or specification, that might rebut the claim of invention; but there was no evidence of that kind; and he left it to them to say whether the invention had been in public use and operation before the granting of the patent. They found that it had not; and on the motion for a new trial, the judges thought there was no reason to find fault with the verdict.

Losh's patent was for improvements in the wheels of railway carriages, and these improvements consisted in constructing the pieces composing the entire wheel of malleable iron, and then welding them together. It was contended by the defendant in the case of Losh v. Hague (1 W. P. C. 202) that the invention was not

new, inasmuch as one Paton had, previously to the date of Losh's patent, and under a patent of his own, specified a mode of constructing wheels of wrought iron, which differed little, if at all, from those patented by Losh; moreover, that although the first wheel made under Paton's patent was riveted, all Paton's other wheels, thirty pairs in number, were made with the circumference of the inner rim entirely of wrought iron, and then welded into one piece. The question you have to try,' said Lord Abinger to the jury, on the originality of Losh's invention, is not whether Paton's patent contains that perfect periphery that is required in this case, but whether wheels have been publicly made on this principle.' (The jury by their verdict found that wheels. had been previously made on the same principle as Losh's wheels.) If,' continued his lordship, the wheels had been made and. sold to any one individual, the public's not wanting them because there were no railways, their not being adapted to any particular use, which at that time was open to the public to apply them to, makes no difference. You have it in evidence that thirty pairs were made with a complete continuous circumference all round. If they were so made and sold, or used at all, though not for any purpose that then made them popular or desirable, still they were made with that particular advantage which is claimed by Losh's patent, namely, a periphery made of one continuous piece of wrought iron, as well as the spokes. But that is not all the evidence; there are two parties from Manchester. One Horsefall says that he remembers, nearly twenty-eight years ago, that there were three trucks, having each three wheels, and those wheels were made of wrought iron spokes in a wrought iron circumference, and there is one exhibited before you which was actually in use at that time; the other, Roberts, confirms that, and has stated