All the legal cases that in any way bear on the validity or ownership of this complex and tangled series of patents are here summarized :

ELMORE v. VAN METER. The Elmore company, in 1902, opposed the granting of patents to Van Meter in Peru,, but, after a hearing, the patents were granted. A compromise was. subsequently effected between these two interests, by which the Van Meter patents were absorbed by Elmore.

SULMAN & PICARD v. WOLF. Decision given in May, 1905. This was an action brought in the Chancery division of the English courts, before Mr. Justice Buckley, by Sulman & Picard, metallurgical chemists, against Wolf, inventor of a flotation process, for fees that Sulman & Picard claimed were due for work done on Wolf's process. Wolf counter-claimed that Sulman & Picard had violated their contract with him in that, being employed by him to investigate his process, they used the information obtained thereby, and took out patents in respect to certain discoveries that they made for him, and which they ought to have handed over to him. The counter-claim stated that this claim was unwarranted for the reason that Sulman & Picard had notified Wolf before he employed them" that they were interested professionally and commercially in another similar oil process belonging to Minerals Separation, Ltd. They informed him that, in view of their opinion that this new process would prove superior to Wolf's, they did not feeljjustified in accepting fees from him, and suggested he retain the services of someone else to conduct his trials. Nevertheless, Wolf entered into an agreement whereby Sulman & Picard were, among other things, to give him the benefit of all discoveries made in the course of their investigation of his process. The learned judge held that they had fulfilled every undertaking of the contract, and in the course of his judgment construed the meaning of various oil patents submitted to him as follows : The Elmore process was for treating crushed ore by mixing with water and oil, so that the gangue shall become loaded with water and shall sink, and the sulphides shall become engaged by the oil, and shall float as by little rafts of oil. The process in which Wolf was interested was a process of the Elmore type, and was the subject of a patent by Scammell. Scammell's improvement on the Elmore process consisted in increasing the viscosity and cohesion by treating the oil with sulphur chloride. As a result of the investigation of this Elmore-Scammell process by Sulman & Picard, Wolf ultimately took out a patent for a process that was of the Elmore-Scammell type, with this improvement : that after the oil had rafted off the sulphides, air was blown through the tailing to recover the oil that had been lost in the tailing. The other process that Sulman & Picard were investigating was different altogether. In this process, belonging to the Minerals Separation, Ltd., a very small quantity of oil was used, the original object being not to float the sulphides, but to collect the sulphides together in the form of granules and make them sink, adding just enough oil to act as a cement for the granules. Later this process was improved by the Minerals Separation, Ltd., in such a way that by introducing air into the pulp the granules could be made to float by the attached airbubbles. This was not flotation by oil, but flotation by air. The only point of resemblance between the Elmore-Scammell-Wolf process and the process of Minerals Separation, Ltd., was that they both used a jet ; but the object of the jet in Wolf's case was to recover lost oil, while in the other case it was used to make the sulphides float, and so recover them. The learned judge, therefore, held that Sulman & Picard had discharged every obligation faithfully, and that Wolf must pay the fees agreed upon.

DE BAVAY v. MACQUISTEN. Decision delivered in Jan, 1907. Macquisten applied for a patent in Australia for his process, which involved the use of the surface tension of water applied in a slowly revolving tube. De Bavay opposed the granting of this patent, but, after hearing the evidence of both parties, the Commissioner decided that Macquisten was entitled to his patent.

POTTER v. THE BROKEN HILL PROPRIETARY COMPANY. Decision delivered in February, 1907. This was an action brought in Australia by Charles V. Potter, inventor of an acid-flotation process, against the Proprietary company for infringement by the use of the Delprat process. Delprat pleaded that Potter's patent was invalid because :

(1) It will not do as much as it professes to do with any sulphide ores.

(2) That with some sulphide ores it will not work at all.

(3) That with many sulphide ores it will not work with any result that could be useful.

(4) That it will not work with the class of ore mentioned in the specification.

(5) That it will not work with slime.

(6) That although the patentee says that any acid may be used, some acids will not be operative, and an acid that will be operative on one ore will not be operative on another. Much detailed evidence was presented to the Court on these points, and Mr Justice a Beckett decided that Potter's patent was invalid for want of utility, for the following reasons : " (a) That with many ores no such separation can be " effected, although partial separation can be effected. " (b) That in many instances in which high percentages of " separation have been obtained in flotation of sulphides a large " percentage of gangue has been floated with the sulphides. " (c) That some ores are not amenable to the process under " any condition. " (d) That in cases in which only part of the sulphides are " floated no reason can be assigned for the other part of the sul- " phides failing to float, and no repetition or variation of the " process will make this part float. " (e) That no assay or examination of a particular ore will " enable an operator to discover whether with that ore the process " will be successful wholly or partially, or will fail altogether."

On the other hand, the court held that the Delprat process would have been an infringement if Potter's patent had not been invalid by reason of having been badly drawn up. There was no question but that Potter had a novel idea.

This unsatisfactory decision was at once appealed to the High Court of Australia, but before the High Court was called upon to revise the findings of Mr. Justice a Beckett, a compromise was effected as follows :

(1) Potter granted to the Proprietary company the right to use free his process in Australia.

(2) The Proprietary company assigned to Potter all the Delprat patents in Australia.

(3) The Proprietary company paid Potter 10,000 in cash.

(4) Each party paid its own costs.

In view of the compromise it would seem that the defendants had little confidence in Mr. Justice a Beckett's decision.

ORE CONCENTRATION COMPANY, LTD., v. WEBSTER AND OTHERS. Decision rendered in October, 1908. This was a suit brought in the King's Bench division of the English courts before Mr. Justice Darling by the owners of the Elmore process against Webster and others for damages for non-fulfilment of contract. The Elmore company and Webster et al. had entered into a contract some years before, wherein Webster et al. were given an option on the rights of the old Elmore process for Australia at a fixed price, and were to be allowed to inspect and investigate the Elmore process previous to exercising the option. Among other clauses in the option was one providing that any patents for improvements in oil-concentration acquired in any way by Webster and associates should become the property of the Elmore company, and be treated for the purpose of the option as if they were the original patents. After investigating the Elmore process for some time, Webster and associates come to the conclusion it was not what they wanted and they allowed their option to expire, and so waived all their rights and lost the payments they had already made. Some time later, A. E. Cattermole brought on the market his oil process, and after offering to sell the patent rights to the Elmore company and others unsuccessfully, he offered them to Webster and associates. After due consideration, Webster and associates formed a syndicate, into which they took a number of other people, and this syndicate purchased the Cattermole, Froment, Sulman & Picard, and other oil-process patents. Webster and Ballot, two of the holders of the old option on the Elmore process for Australia, were directors of the new syndicate, which was called Minerals Separation, Ltd. The Elmore company then brought a suit against Webster, Ballot, and Hay, to enforce the clause in the contract above mentioned.

After hearing evidence on the negotiations leading up to the option, Mr. Justice Darling delivered judgment to the effect that the particular clause had been introduced into the contract without authority after it had been signed, sealed, and delivered by both parties, and that therefore the Elmore company was not entitled to any redress.

The Elmore company appealed from Mr. Justice Darling's decision to the Court of Appeal, which court, after hearing the arguments of counsel, ordered that the judgment of Mr. Justice Darling be set aside and a new trial held.

The new trial was held in the Chancery division of the English courts before Mr. Justice Parker. In this trial the Elmore company introduced evidence to show that the Minerals Separation processes were oil-flotation processes, similar to the Elmore processes, and that they belonged rightfully to the Elmore company under the terms of the clause of the option above-mentioned. Webster and associates introduced evidence to show that they had never owned these patents ; that they were never in their possession but had been bought by a trustee of the syndicate, and had passed directly from the inventors through a trustee to the Minerals Separation Syndicate. When the proceedings reached this stage, the learned counsel for the plaintiffs asked the Court for a moment to confer with the learned counsel for the defendants. Thereupon it was mutually agreed between the plaintiffs, the defendants, and the Court, that the proceedings be stayed on the following terms :

That both parties to the action pay their own cost.
That the option agreement be treated as if the clause referred to were struck out altogether.
The result of this piece of litigation leaves the impression that it was unnecessary and wasteful.

ELMORE v. MINERALS SEPARATION, LTD. Decision delivered May, 1909. The Minerals Separation, Ltd., through Sulman, Picard, and Ballot, applied for a patent in Germany. This was opposed by Elmore, but the patent was granted. The Elmore company appealed from the decision of the Patent Office to a higher court, which reversed the decision of the Patent Office.

MINERALS SEPARATION, LTD., v. NORRIS. Decision rendered May, 1909. Dudley Norris applied for a patent in England for a method of introducing air into an oiled pulp. This was opposed by the Minerals Separation, Ltd., and after hearing evidence the law officer held that practically all but one of Morris's claims were anticipated by the earlier patents of Hoover & Sulman.

MINERALS SEPARATION, LTD., v. POTTER. Decision rendered July, 1909. After the Potter company had compromised with the Delprat interests they applied for amendments in Australia with a view to overcoming the invalidity in their patents as indicated by Mr. Justice a Beckett. These amendments were opposed by the Minerals Separation, Ltd. The case was heard before the Commissioner of Patents, and some of the amendments were granted and others rejected. The Minerals Separation, Ltd., appealed from the decision of the Commissioner to the High Court of Australia, and this court decided in favour of Potter, and the amendment was granted. In December, 1909, Minerals Separation, Ltd., applied to the Privy Council in London for permission to appeal from the High Court of Australia, but the application was denied on the grounds that the case could only come before them on a question of infringement.

BRITISH ORE CONCENTRATION SYNDICATE, LTD., AND ALEXANDER STANLEY ELMORE, v. THE MINERALS SEPARATION, LTD. Decision rendered in November, 1909. This was a suit brought by the Elmore interests, owners of an oil-concentration process, asking for " an injunction restraining the defendants from using ".ores or mineral substances treated by any one of the processes " described and claimed respectively in the specifications of " letters patent No. 21,948 of 1898, and 6,519 of 1901, of which " the plaintiffs are the registered legal owners." The trial case was heard in July, 1908, by Mr. Justice Neville, of the High Court of Chancery, who, after an inquiry lasting seven days, pronounced judgment to the effect that the Minerals Separation, Ltd., owners of the Minerals Separation process, were not infringing. In his judgment Mr. Justice Neville made the following points :

(1) The selective action of oil for sulphides was known before Elmore obtained his patents, and was disclosed in prior expired patents. (2) Elmore's patent was for a process wherein a large quantity of oil was used, sufficient to carry all the sulphides to the surface by the buoyancy of the oil. (3) The Minerals Separation process used only an infinitesimal amount of oil for the purpose of attaching air-bubbles to the sulphides, and so causing them to float by the buoyancy of the airbubbles. (4) The use of acid in oil processes was known before Elmore obtained his patents and was disclosed in prior expired patents.

Mr. Justice Neville then summed up in these words : " I think, therefore, in that case, whether you take it that " the patent is confined to the 1898 patent, or whether you take " it generally, the defendants have not infringed, or they have " infringed a patent which has no validity, and consequently no " relief can be granted against them."

The plaintiffs (the Elmore company) appealed from this decision and the appeal was heard in the Court of Appeal before the Master of the Rolls, Lord Justice Fletcher Moulton, and Lord Justice Farwell, in November, 1908. Judgment was rendered on December 2, reversing the decision of the lower court and finding that Minerals Separation, Ltd., were not infringing the 1898 patent, but were infringing the 1901 patent. An injunction was granted as applied for. Lord Justice Fletcher Moulton's idea of the patents in question was as follows :

(1) That the first Elmore patent was not anticipated by previous expired patents. (2) That if Minerals Separation used a thin oil they would not infringe Elmore. (3) That the second Elmore patent was not anticipated by previous expired patents. (4) That the Minerals Separation infringed the second patent by using acid.

The Court of Appeal thereupon reversed Mr. Justice Neville's decision and granted the injunction against Minerals Separation, Ltd.

The Minerals Separation, Ltd., appealed from this decision to the House of Lords the court of last resort and on November 16, 1909, the Lord Chancellor and Lords Halsbury, Ashbourne, Atkinson, and Shaw, reversed the judgment of the Court of Appeal and upheld the judgment of the trial court as follows :

The Lord Chancellor held that the Elmore patents were drawn up with great subtlety in order that the claims might be expanded or contracted as occasion might require in the interests of the patentee ; that the only definite claim in the patent was for acidulation, and that this was anticipated in the expired Everson patent ; therefore the Elmore patents could not be sustained.

Lord Halsbury held that the Elmore and the Minerals Separation processes were essentially different, in that the one was based on the selective action of oil, and the other on surface tension ; that Elmore had no valid claim to acidulation, because it was known and had been previously described ; that the Elmore patent should not be upheld, if for no other reason than because of its ambiguity.

Lord Atkinson held that the Elmore process was the addition of a small quantity of acid and a relatively large quantity of oil to a mixture of ore and water, where the oil, in accordance with some obscure law of affinity, seized upon the minute particles of ore in preference to the earthy particles, and, by the buoyancy of oil, floated them to the surface ; that the Minerals Separation did not infringe this process because their process was one where they made use of the known selective action of oil, yet the oil was used in relatively small quantities, and the metallic particles were only coated with a thin film of it, and the lifting force was found, not in the buoyancy of the oil, but in the natural buoyancy of the air-bubbles, which, introduced into the mass by violent agitation, envelop or become attached to the oiled mineral particles and raise them to the surface.

Lord Shaw held that the two processes were essentially different, so much so, that apart from the question of the prior state of knowledge of the art, there was no infringement.

Lord Ashbourne concurred with the decision of their lordships, thus making the judgment of the Court unanimous.