Potter's Sulphide Ore Treatment Ltd v Sulphide Corporation Ltd [1911] HCA 35; (1911) 13 CLR 101 (11 August 1911)

Potter's Sulphide Ore Treatment Ltd Plaintiffs, Appellants; and Sulphide Corporation Ltd Defendants. Respondents.

This is an action for the infringement of a patent, in which the specification has been amended. The nature of the invention came before this Court for consideration on an application to amend the original specification. I then described it thus: Minerals Separation Ltd. v. Potter's Sulphide Ore Treatment Ltd.[1]:—"The invention was, as appears from the evidence, a new principle; the principle that the patentee Potter had discovered being that the application of an acidulated solution of varying degrees of strength to certain sulphide ores would cause the sulphides to separate from the gangue, and to float to the surface so that they could be skimmed off. That was the nature of the invention, but as you cannot obtain a patent for a principle, it was necessary for the patentee to go on and explain how that idea or principle could be put into practice, which he did."

I will read another passage from the same judgment, at p. 791, which is a quotation from the speech of Lord Davey in Chamberlain v. Mayor of Bradford[2]:—"The question in every case is, in what consists the originality and merit, or, to use the well known phrase of Lord Cairns, the pith and marrow of the patented invention? If that includes the discovery or suggestion of a new principle as well as the means of carrying it into effect, an infringer is not entitled to take the principle although he uses somewhat different machinery for the application of it to a practical purpose." The statement of claim in the present case, after setting out the original specification and the amended specification, alleges that the defendants are using plaintiffs' process or a process and method only colourably differing therefrom. The plaintiffs' case is, in fact, based upon the doctrine stated by Lord Davey in the passage I have just read.

The defendants in their defence denied the infringement. An application was then made, in accordance with the practice in the Supreme Court of New South Wales, to the Chief Judge in Equity for leave to deliver certain interrogatories with respect to the alleged infringement.

The first interrogatory reads thus:—"Was not the defendant corporation at the date of the institution of this suit and/or at some and what date or dates prior thereto and subsequent to the sixth day of November one thousand nine hundred and five using in the State of New South Wales a flotation process or processes for separating metallic sulphides from sulphide ores in which the ore and/or tailings from the ore in a pulverised condition and/or slimes were placed in a vessel provided with internal stirrers and mixed with a solution containing water and sulphuric acid or some other and what acid?"

That is practically taken from the description of the process in the specification. The specification, however, had said this (paragraph 10 of the statement of claim):—"The crude ore, concentrates, tailings or slimes, after being pulverised, are placed in a suitable vat or vessel, and a solution is then added, such solution consisting of water with the addition from one per cent. to ten per cent. of sulphuric acid or any other suitable acid (but preferably sulphuric acid) the acidulated strength of the solution being determined by the quality or nature of the sulphide ore to be treated."

Later on reference is made in the specification to the proportion of solution to be applied per ton of ore. It is said to be approximately 250 gallons per ton, but varying according to circumstances.

I have stated the first part of the first interrogatory. It then went on to require the defendants to state the proportion and percentage that the acid bore to the solution in the process or processes used by the defendants. There were other interrogatories raising substantially the same question.

Before referring to what took place before the learned Chief Judge, I should state the question which will arise under these circumstances at the trial. A question may arise, and probably will arise, upon the construction of the specification, whether the patent is limited to the use of an acidulated solution of a strength between one per cent. and ten per cent. If it is, and the defendants have not used a solution between these limits, the plaintiffs will fail. Another view that may possibly be set up is that the patent includes the use of an acidulated solution of any strength whatever. In that case, if the defendants have used a solution of that sort of any strength, the plaintiff will succeed.

But there is a third view, that although the defendants may not have used a solution of a strength between these limits, yet the departure from them is a mere mechanical or chemical equivalent for the variation in point of strength. Whether that is so is a question of fact; whether the fact, if established, is material is a question of law.

The information, therefore, which the plaintiffs desire is whether the defendants are in substance, though not in the letter, using the process described in the plaintiffs' specification, substituting for a part of the plaintiffs' process which they omit something which is a mere mechanical or chemical equivalent for it. That is the point to which the interrogatories are sought to be directed.

When the matter came before the learned Chief Judge in Equity he disallowed the second paragraph of the interrogatory asking the defendants to state the proportion and percentage of solution they were using, and he disallowed some other interrogatories.

An appeal was then made to the Full Court. We have not had a formal statement of the reasons given by the learned Chief Judge in Equity, but it appears that a very short time before there had been a litigation before him relating to a patent of a somewhat similar nature, when he had intimated that he thought that interrogatories with respect to patents should be kept within the limits of specific questions based upon the specification itself. The Full Court expressed no opinion as to the correctness of that principle, but they suggested that such a test would exclude some questions which might properly be allowed on interrogatories. The learned Chief Justice, who delivered the judgment of the Court, went on to express his own view as to the limits which should be put upon interrogatories. I find this passage in his judgment:—"The larger number of the questions or parts of questions which were disallowed are not questions the answers to which would decide an issue in the case; they are simply questions the answers to which might help, together with other facts, in establishing a body of facts from which an inference would be drawn confirmatory of our charge that the patent has been infringed. That seems to me too remote to entitle a party to insist on that kind of interrogatory." With great respect, I should be inclincd to finish the sentence by saying that that seems the very object of interrogatories. The learned Chief Justice went on to add, after referring to a particular question:—"Having that, the answer is still a very long way from being decisive of the issue; it would only show that in certain aspects the results produced by one process are similar to the results produced by the other process, and it may be evidence, taken with a great many other facts, that would justify the inference that the patent is being infringed. But it is still touching only the very skirts of the evidence, and again I say it illustrates the distinction between what is directly connected with the issues and what is remotely and speculatively connected with them."

The Full Court dismissed the appeal altogether. I entirely agree that the connection must not be remote or speculative. I think that the principles which govern the admissibility, if I may use the expression, of interrogatories are tolerably clearly established. In many cases a question of discretion arises. It may be that an interrogatory is one which it is lawful to put, but which the Court in its discretion will not allow to be put, as, for instance, if a man were interrogated in a patent case about some secret process which he himself had invented and which had never been disclosed. In such a case the Court in its discretion might refuse to allow the interrogatory to be put. But no question of discretion arises in this case. The only question is whether the interrogatories sought to be put are so framed that they are proper matters as to which the defendants may be asked to state the truth. I will refer to two authorities on the principle to be applied in dealing with the matter. The first is Marriott v. Chamberlain[3]. At the conclusion of his judgment Lord Esher M.R. after pointing out that "it is not permissible to ask what is mere evidence," says:—"With these exceptions it seems to me that pretty nearly anything that is material may now be asked."

The other case is Plymouth Mutual Co-operative and Industrial Society Ltd. v. Traders' Publishing Association Ltd.[4] also before the Court of Appeal. I will read a passage from the judgment of Stirling L.J. which is itself a quotation from the judgment of Lord Esher M.R. in the case of Hennessy v. Wright[5]: "The objection taken by the defendant is, that the answers to the interrogatories in question cannot disclose anything which can be fairly said to be material to enable the plaintiff either to maintain his own case or to destroy the case of his adversary. It must be admitted that, if the answers could be material for either of these purposes, the interrogatories ought to be answered, but I think it must equally be admitted that, if the answers could not be material for either of these purposes, we ought not to order the defendant to answer. The question, therefore, is, whether the answers to the interrogatories objected to could, in our view, be material for either purpose."

The question then for determination in this case is whether the answer to inquiries as to the proportion of acid used by the defendants could be material. The nature of the plaintiffs' case I have already stated. If they can establish that although the defendants use an acid in a different proportion to that mentioned in the specification, yet they substitute for it something which is scientifically a mere equivalent for it, then it would be very material to the plaintiffs' case. The object of interrogatories, I suppose, is to discover the truth. It has also the advantage of saving expense. When inquiry is made as to a matter which is entirely within the knowledge of the defendant and not within the knowledge of the plaintiff, and is relevant to the case, I do not know of any rule why the defendant should not be interrogated about it. The practice of interrogatories came from the Chancery Court, and the common form there was to interrogate the defendant about everything alleged in the bill, and every interrogatory used to conclude with the words: "And if not, how otherwise, and does the defendant make out to the contrary?"

For these reasons we are of opinion that the question as to the proportions in which the acid is used by the defendants was a relevant question, and ought to have been admitted.

The third paragraph of the first interrogatory reads:—"If yes, also describe in detail the process or processes so used by the defendants and the period or periods of time during which each process was used."

It was objected that that was asking too much, that it was asking things that might not be relevant to the case at all, and that all the plaintiffs were concerned with knowing was what the defendants were doing so far as their process did not resemble the plaintiffs'; and that argument has a good deal of weight. In the course of the case I suggested that that interrogatory might be allowed in a modified form by asking the defendants to state the particulars in which their process, if they admit they are using this acidulated process, differs from the process described in the plaintiffs' specification. Mr. Leverrier very properly admitted that he could not dispute the rule laid down by Lord Esher in Marriott v. Chamberlain[6] that any facts relevant to the matter in issue may be the subject of interrogatories, and said he could not see why any question coming under the rule of law I have suggested should not be asked. We think, therefore, that the question may be asked in that modified form. The tenth interrogatory asked the proportion between the quantity solution and the weight per ton of ore as used in the defendants' process, and the learned Judge of first instance limited that also to the particular proportion mentioned in the plaintiffs' specification. The reasons which I have given with reference to the interrogatory concerning the strength of the acid are equally applicable to that question.

There was also a series of questions and interrogatories, numbered 11 to 19, which relate to quantities and materials dealt with by the defendants, and may be material as to damage and on other questions. But, before the learned Chief Judge, it was agreed that those questions should stand over till after an inspection of documents, which had been ordered; and the learned Judge made no order as to them. There was an appeal from the whole of his order, and the whole appeal was dismissed. The question whether any of these interrogatories from 11 to 19 can be properly allowed was not argued, but it was agreed here that they should stand over; so that in ordering them to stand over we are not expressing any opinion inconsistent with that of the Supreme Court. We simply accede to the request made and consented to, to carry out the arrangement made in the Judge's Chambers.

The other points as to which the learned Chief Judge either disallowed the whole of the interrogatories, or modified them in the way objected to by the plaintiffs are not sufficiently material to call upon us to vary the order which has been made; but for the reasons I have given I think that the plaintiffs are entitled to more discovery than has been allowed, and that the proper order to make will be to discharge the order of the Supreme Court dismissing the appeal, and to substitute for it the following:—

[1] [1909] HCA 42; 8 C.L.R., 779, at p. 790.

[2] 20 R.P.C., 673, at 684.

[3] 17 Q.B.D., 154, at p. 163.

[4] (1906) 1 K.B., 403, at p. 416.

[5] 24 Q.B.D., 445, at p. 447.

[6] 17 Q.B.D., 154.

High Court of Australia

Potter's Sulphide Ore Treatment Ltd v Sulphide Corporation Ltd [1911] HCA 35; (1911) 13 CLR 101 (11 August 1911)

HIGH COURT OF AUSTRALIA