197

0,-3

divided zinc should be used as soon as possible after it has been produced, either by one of the methods above described or in any other suitable manner. " The precious metals may be separated from any excess of zinc after separation of the solution by distillation, or the larger portion of the precious metals may be separated from excess of zinc by sieving (by preference under water), when, with a suitable sieve, the greater part of the precious metals will pass through, the greater part of the zinc being left on the sieve. " Having now particularly described and ascertained the nature of our said invention, and in what manner the same is to be performed, we declare that what we claim is : (1.) In a cyanide process for extracting gold and silver from ores or other compounds with an alkali or alkaline earth preparatory to subjecting same to the action of cyanogen or of a cyanide. (2.) The employment of zinc in a fine state of division for the purpose of precipitating gold and silver from cyanide, chloride, bromide, thio-sulphates, sulphate, or other similar solutions." The invention, therefore, with regard to the use of cyanide of potassium as a solvent for gold and zinc as a precipitant is certainly not one that MacArthur-Forrest can reasonably claim, as it is no invention of their own. Mr. William Skey, the Government Analyst in the Colonial Laboratory, Wellington, in a paper published in the "Transactions of the New Zealand Institute," in 1875, pages 335 to 337, clearly shows that cyanide of potassium is a solvent for gold, and that zinc is a precipitant. This is also shown in the Chemical News, circulating in the colony long before Messrs. Mac Arthur-Forrest laid claim to the invention. Again, when we come to the use of zinc as a precipatating agent, this was made known some years before MacArthur-Forrest ever made any claim for the use of zinc, and therefore that cannot be said to be an invention of their own. It therefore stands in the same way as their claim for the sole use of any solution containing cyanogen. In delivering judgment in the case previously quoted Mr. Justice Bonier showed the absurdity of Mac Arthur-Forrest's patent for the use of cyanogen compounds when he remarked : " If Messrs. Mac Arthur and Forrest's patents were held to be valid, the real inventor, or person taking out letters patent for any invention some years prior, would be debarred from the use of his patent, as it would be an infringement of the Cassel process." There cari be no disputing the fact that Messrs. Mac Arthur and Forrest deserve credit for the revival of an old invention and for improvements in the process of extracting the precious metals from their ores ; but, whilst acknowledging this and the benefits derived by the mining community in New Zealand through the introduction of the Cassel process into the colony, Messrs. Mac Arthur and Forrest are not entitled to lay claim, and hold letters patent, for an invention previously described by other persons, and made known to the public long before the gentlemen mentioned made application for patent rights. The company which had purchased Mac Arthur and Forrest's patents for using cyanide of potassium in the extraction of gold and silver from the ore was confident, after so many able men had. given evidence on its behalf, that on appeal to a higher court Judge Eomer's decision would be set aside, and notice of appeal was given; the latter being heard before Lord Halsbury, Lord Justice Linley, and Lord Justice A. L. Smith, who, after going fully into all the particulars of the case, delivered their judgment on the 9th April last, as follows : — Judgment of the Court of Appeal. Lord Justice A. L. Smith: Messrs. Mac Arthur and Forrest's patent, for the infringement of which this action is brought, bears date the 16th July, 1888, the provisional specification having been filed on the 19th October, 1887, and it is for improvements in extracting gold and silver from their ores by means of what for the present we will take to be the application to the ore of a small quantity of a cyanogen-yielding substance in solution. We shall hereafter, for brevity, call these substances cyanide of potassium. The defendants deny the infringement, and also asserted that the plaintiffs' patent was invalid, firstly, by reason that the discovery as claimed contained neither novelty nor invention; and, secondly, by reason of prior anticipation. A further point was raised, which is, that if the specification is to be read as the plaintiff's read it, the defendants contend that there is such disconformity between the complete and the provisional specification as to be fatal to the plaintiffs' claim. The defendants do not deny the utility of the plaintiffs' invention, but they dispute the great commercial importance claimed for it by Sir Eichard Webster for the plaintiffs. As regards the infringement, the defendants, during the first five days of the trial, strenously insisted that their patent, which was said to be an infringement of the plaintiffs' patent, was for the. extracting of gold from its ore by means of the conjoint current of electricity and cyanide of potassium, and was therefore no infringement of the plaintiffs' patent, the electricity which they used being a material part of their invention. When, however, their witness, Mr. Harland, was being cross-examined, and they were challenged to refer to independent experiment and trial whether their electricity as used was not in reality a myth, they refused to do so, and admitted that they were infringers of the plaintiffs' patent, and thus this point became disposed of. In considering the question of want of novelty and invention, it is necessary to state what we find to have been established in this case. It was proved that, for many years prior to the patent in question, it was common knowledge that cyanide of potassium would act as a solvent of gold in ' a finely-divided or precipitate condition in the same way as many other solvents would act, of which, perhaps, the strongest is aqua regia. There is no doubt as to this, and it is common ground. It was also in our judgment proved that prior to the plaintiffs' patent it was not known that cyanide . of potassium would act as a solvent so as to extract gold from its ore. We leave out silver, for it has nothing to do with this case. The way in which gold had theretofore been extracted from the ore in which it was contained had been by subjecting the ore which had been crushed, and which contained the gold, to a process which is called the amalgamation process, and then by again subjecting that ore to a second process, called the chlorination process, further gold was thereby obtained. These two processes, however, left a residuum of gold in what are termed the tailings, and this residuum could not by any known process at the date of the plaintiffs' patent be commer^