TURNER'S PATENT.

Letters patent, 26th February, 21 G. 3, a. d. 1780, for "a Title. method of producing a yellow colour for painting in oil or water, making white lead, and separating the mineral alkali from common salt, all to be performed in one single process."

TURNER V. WINTER.

Hil. Vac. A. D. 1787. Cor. Buller, J.

directions which

This was an action for infringing the above patent. At the A patent is void if the specificatrial before Buller, J., a verdict was found for the plaintiff, tion is ambiand on a motion to set aside that verdict and grant a new trial, guous, or gives these facts were reported. The plaintiff within the usual time tend to mislead had enrolled the following specification; "Take any quantity of the public. lead and calcine it, or minium, or red lead, litharge, lead ash, Specification. or any calx, or preparation of lead fit for the purpose; to any given quantity of the above-mentioned materials, add half the weight of sea salt, with a sufficient quantity of water to dissolve it, or rock salt, or sal gem, or fossil salt, or any marine salt, or salt water, proper for the purpose; mix them together by trituration till the lead becomes impalpable, or sufficiently comminuted. When the materials have been ground, let them stand for twenty-four hours, in which time the lead will be changed to a good white, and the salt decompounded: if not, the trituration must be repeated with the further addition of salt, till the white colour be obtained; the decomposition of the salt may also be brought about by digestion or by calcination. The materials may be suffered to remain together before the alkali is separated by the addition of water, for a longer time than is specified above, according to the discretion of the operator, and the end he wishes to obtain. The yellow colour is produced by calcinating the lead after the alkali has been separated from it, till it shall acquire the colour wanted; this will be of different tints, according to the continuance of the calcination, or the degree of heat employed. The white lead must be finished by repeated ablutions, and by bleaching it till the white be made perfect."

On the part of the plaintiff it was proved, that the first effect of the process was the separating of the mineral alkali from common salt; that that produced white lead, and that by continuing the process to a certain degree, and afterwards exposing the matter, the yellow colour was produced. That as the specification required the heat to be continued till the colour was obtained, any person trying the experiment would necessarily be

led to fusion. That a chemist would see by the specification, that if less heat would not answer the purpose, he must go on to fusion. The difference between fusion and calcination, both of which proceed from different degrees of heat operating upon the subject-matter, was, that the substance to be calcined continued in a solid form, whereas fusion is a liquid state to which the substance may be reduced by continuing the heat. Instances were produced of persons who had made the colour by the help of the specification, after trying some experiments. In trying those experiments, minium had been fused in the first instance. The white lead produced by the following directions in the specification was not what was sold as such, but a white substance, the basis of which was lead.

For the defendant it was proved, that the patent colour could not be made by following the directions of the specification. For calcination was not sufficient to produce the effect intended; it was necessary to go on to fusion. That as it appeared upon the specification minium, or red lead, might be considered most convenient for the purpose, because a previous process was necessary to reduce lead to minium, or litharge, before the other parts of the process were to be begun, minium and litharge differing only in having undergone different degrees of calcination. But that minium would not produce the effect unless first fused. And that if red lead were calcined, the experiment would not succeed without fusion; whereas, according to the terms of the specification, fusion should be cautiously avoided. That the specification was calculated to mislead also with respect to the salts. For fossil salt is a generic term, including all mineral salts; but only one species of fossil salt, namely, sal gem, has marine acid, without which the colour could not be produced. That several persons had tried to make white lead by the specification, but had not succeeded. They could only produce a greyish white powder, quite unfit for painting, and not merchantable.

BULLER, J. after reporting these facts, observed, that at the trial three objections had been taken to the specification. 1st. That, after directing that lead should be calcined, it directed another ingredient to be taken, which would not answer the purpose, viz. minium. Neither was it said that the minium should be calcined or fused; but if it had any reference to the preceding words, then it should be calcined, which would not produce the effect, fusion being necessary. 2d. That "fossil salt" was improperly mentioned. There were many kinds of fossil salt, only one of which, viz. sal gem, would answer the purpose, because it must be a marine salt. 3rd. That all these things put together did not produce the thing intended. And that the patent was for an invention to do three things in one process, whereas one of them, viz. white lead, could not be pro

duced at all; for that a white substance like white lead remained, applicable only to some of the purposes of common white lead. The learned judge then said that at the trial he had told the jury that if any of these objections were well founded, it would avoid the patent.

Erskine and Piggot showed cause against the rule for granting a new trial, and contended that in actions for infringing patents, it is not necessary for the plaintiff to give any evidence to show what the invention is, but that it is incumbent on the defendant, if he objects to the specification, to show that it is defective, and that persons acquainted with the subject could not, by the assistance of the specification, effect the thing intended. The consideration which the patentee gives for his monopoly is the benefit which the public are to derive from his invention after his patent is expired; and that benefit is secured to them by means of a specification of the invention. But it is not necessary that that specification should be such as that persons unacquainted with the terms of art, which must necessarily be used in writing it, should be able to understand it. It is sufficient if persons of skill can understand the process by means of the specification, so as to keep alive the discovery after the patentee's exclusive title is expired.

The first objection which has been raised against the sufficiency of the specification has no weight; for though the direction to calcine is applicable to all the ingredients in the first part of the description, yet scientific persons would instantly discover what degree of heat was necessary to be used to each of those ingredients, and that minium, being already a calx, must be fused (a). Secondly. The heat is ordered to be continued till the experiment succeeds, and the colour is produced. Fusion is a necessary consequence of continuing the heat, and this direction would be sufficiently understood by all persons acquainted with the subject.

As to the second objection, with respect to the "fossil salt." The specification begins with "sea salt," which is the genus; then it afterwards states not "any fossil salt," but "fossil salt," or" any marine salt;" the marine salt is therefore the basis of the experiment. So that no fossil salt but what is likewise a marine salt, can be taken under this description.

The answer to the third objection is, that a species of white lead is produced, though not the common ceruse; and the patent does not profess to make the common white lead. Besides, the making of white lead was not the subject of the present ac

(a) The argument that a defect or misstatement in a specification, by which a scientific person or even a common workman would not be misled, is not such a defect as will vitiate a specification, was urged with great force in the recent case of Neil

son v. Harford, but the Court of Exchequer were unanimously of opinion, that a statement untrue in fact could not be corrected by such knowledge or experience, and that such an error or misstatement would be a fatal defect. Ante 66, n.

A patent being a monopoly

against law, but for the subse

quent advan

tage to the public,

intentionally in

tion, which was for making the yellow colour; which accounts for the plaintiff's not being prepared to prove this part of the specification (b). Upon the whole, this was a mere matter of evidence, as to the sufficiency of the specification, upon which the jury have exercised a sound discretion (c).

Bearcroft, in support of the rule, was stopped by the court. ASHURST, J.: I think that, as every patent is calculated to give a monopoly to the patentee, it is so far against the principles of law, and would be a reason against it, were it not for the advantages which the public derive from the communication of the invention after the expiration of the time for which the patent is granted. It is, therefore, incumbent on the patentee to give a specification of the invention in the clearest and most Any ambiguity unequivocal terms of which the subject is capable. And if it troduced, fatal. appear that there is any unnecessary ambiguity affectedly introduced into the specification, or any thing which tends to mislead the public, in that case the patent is void. Here it does appear to me that there is at least such a doubt on the evidence that I cannot say this matter has been so fully and fairly examined as to preclude any farther investigation of the subject. Three objections have been made to this specification. The first is, that in the specification the public are directed "to take any quantity of lead and calcine it, or minium, or red lead;" from whence it is inferred that calcining is only to be applied to lead. I confess, if the objection had rested here, I should have entertained some doubt.

The next objection is, that in the subsequent materials to be added, the public are directed to add "half the weight of sea salt, or sal gem, or fossil salt, or any marine salt." Now "fossil salt" is a generic term, including "sal gem" as well as other species of fossil salt. And I understand that sal gem is the only one which can be applied to this purpose; so that throwing in fossil salt can only be calculated to raise doubts and mislead the public. That word could not have been added with any good view; it must produce many unnecessary experiments; therefore, in that respect, the specification is not so accurate as it ought to have been.

Another objection was taken as to the white lead; to which it

(b) The terms white lead being introduced in the title, the real objection would be that the letters patent were void for false suggestion. The production of white lead, a known article of commerce, and the production of a white substance, however resembling, are very different suggestions and considerations. See ante 41, n.

(c) The sufficiency of the specification in respect of its enabling a competent person to practise the invention and work by it, is a question for the jury, and the plaintiff is bound to give evidence establishing its sufficiency in this respect. It

would appear also to be the province of the jury to find the meaning of words, and what persons of ordinary knowledge of the subject would understand by them. It is then for the court to say whether the letters patent and specification, viewed as one instrument, are sufficient in law.

In this case the plaintiff gave no evidence of the sufficiency of the specification, or that the substances mentioned would answer, or that the yellow could be produced in the manner described. Post 81.

was answered, that the invention did not profess to make common white lead. But that is no answer; for if the patentee had intended to produce something only like white lead, or answering some of the purposes of common white lead, it should have been so expressed in the specification. But in truth, the patent is for making white lead and two other things by one process. Therefore, if the process, as directed by the specification, does not produce that which the patent professes to do, the patent itself is void. It is certainly of consequence that the terms of a specification should express the invention in the clearest and most explicit manner; so that a man of science may be able to produce the thing intended, without the necessity of trying experiments.

BULLER, J.: Many cases upon patents have arisen within our memory, most of which have been decided against the patentees, upon the ground of their not having made a full and fair discovery of their inventions. Whenever it appears that the patentee has made a fair disclosure, I have always had a strong bias in his favour, because, in that case, he is entitled to the protection which the law gives him. How far that law which authorises the king to grant patents is politic, is not for us to determine. When attempts are made to evade a fair patent I am strongly inclined in favour of the patentee; but where the discovery is not fully made, the court ought to look with a very watchful eye to prevent any imposition on the public. Then the question is, The question on whether the present plaintiff has made a fair discovery? I do the specification is, has the plainnot agree with the counsel who have argued against the rule in tiff made a fair saying that it was not necessary for the plaintiff to give any evi- discovery? dence to show what the invention was, and that the proof that the specification was improper, lay on the defendant; for I hold that a plaintiff must give some evidence to show what his inven- A plaintiff must tion was; unless the other side admit that it has been tried and give some evisucceeds. But wherever the patentee brings an action on his ficiency of the patent, if the novelty or effect of the invention be disputed, he specification unmust show in what his invention consists, and that he produced the effect proposed by the patent in the manner specified. Slight evidence of this on his part is sufficient, and it is then incumbent on the defendant to falsify the specification. Now in this case, no evidence was offered by the plaintiff to show that he had ever made use of the several different ingredients mentioned in the specification; as, for instance, minium, which he had nevertheless inserted in the patent, nor did he give any evidence to show how the yellow colour was produced. If he could only make it with two or three of the ingredients specified, and he has inserted others which will not answer the pur- The insertion of pose, that will avoid the patent. So if he make the article for substances which the patent is granted with cheaper materials than those succeed, a fatal which he has enumerated, although the latter will answer the defect.

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dence of the suf

less admitted.

which will not