Then Professor Daniel says, "I am acquainted with the specification. I never knew of the hot blast before. A person accustomed to the manufacture of blowing apparatus would be able to make a beneficial apparatus according to the specification, and most clearly a person accustomed to the process of heating air, and better acquainted with the principle and nature of the invention, would construct a beneficial apparatus. The principle is entirely new; I never saw the process in actual operation. The shape depends upon circumstances-the situation, the heat required, and the power of the blowing apparatus."

Mr. Cooper says, "Looking at the specification, there would be no difficulty in heating the air to a certain extent, so as to use it beneficially, but there would be some difficulty as to obtaining the best mode. I do not believe that has yet been done." And he thinks it probable that improvements will take place to heat the air to a still higher degree of temperature. Upon cross-examination he says, "To some extent one form of vessel would be better than another, but everybody could get some beneficial result so as to make it worth while to employ it."

That, gentlemen, is the evidence, and will you have the goodness to answer me the questions in the form in which I put them?

The jury found as follows:

1. We all agree that shape and form are material to the effect simply—that is, to the extent of beneficial effect produced, not to producing some effect, for some beneficial result would be produced from any shape, and as to producing the extent of beneficial effect, the form and shape are material.

2. We think a man of common understanding, of ordinary skill and knowledge of the subject—that is, of the construction of the old blowing apparatus, would be enabled to construct, according to the specification alone, looking at it altogether, such an apparatus as would be an improvement; that is, would be productive of some beneficial result, sufficient to make it worth while, expense being taken into

consideration, to adapt it to the ordinary machinery in all cases of forges, cupolas and furnaces where the blast is used.

3. We think a person of competent understanding, and ordinary skill and knowledge of the subject of the construction of the air-heating process, would be enabled to construct, according to the specification alone, in the same way, looking at it altogether, such an apparatus as would be an improvement; that is, would be productive of some beneficial result, sufficient to make it worth while, expense being taken into consideration, to adapt it to the ordinary machinery in all cases of forges, cupolas and furnaces where the blast is used.

4. We think a person of common understanding, and ordinary skill and knowledge of the air-heating process, would not be misled by the description of the immateriality of the form and size of the vessel in producing the effect.

5. No person, we think, nor a person of common understanding, and ordinary skill and knowledge of the blowing process, a fortiori, would be misled.

PARKE, B., then directed the verdict to be entered on the issues as follows: On the first, second and third for the plaintiffs; on the fourth for the defendants, upon the construction of the specification, with liberty to move, thinking that, according to the grammatical construction of it, there was an averment that the form and shape were immaterial to the extent of the effect-that it was a misdirection; that there being a misdirection in the instrument itself, it could not be corrected by parol evidence, with liberty to move to enter that verdict for the plaintiffs on that issue; and for the defendants to take the objection in answer contingently, that the patent is void for the bad title if it be open upon the issue, in answer to that application, and to move in arrest of judgment if the verdict is entered for the plaintiffs.

The proceedings on motion for a new trial are reported below.

NEILSON v. HARFORD.

Exchequer, June 9, 1841.

(1 Web. P. C. 328.)

Requisites of Notice of Objections to Specification. Mistake in Specification. Construction. Questions of Law and Fact.

An improvement may constitute an infringement.

A statement in the notice of objections, that the specification is calculated to deceive, is sufficient to let in evidence as to any particular passage being false. Where the objection simply states the specifiction to be insufficient, if the plaintiff is contented to take that as notice, any objection may be made at the trial to show that the specification is insufficient.

If the objections are not sufficiently specific, the plaintiff's course is to apply to a judge for an order for the delivery of a more specific notice.

As a rule, the objection must be more specific than the plea; but if latter sets out the objection in full, an objection in similar terms is sufficient.

Though the title of the patent be ambiguous, if it is explained by the specification, and is not at variance with it, it may be sufficient.

The patentee is bound to disclose in his specification the most beneficial mode with which he is acquainted.

A principle, to be the subject of a patent, must be embodied.

A patent is not vitiated by a mistake in the specification, as where air is called an imponderable substance, or sulphur a mineral; nor by a mistake in a matter foreign to the invention, which cannot mislead; nor by the inaccurate use of words which are explained by the context.

The construction of the specification is for the court, the meaning of the words and surrounding circumstances having been ascertained by the jury.

Motion to enter verdict for the plaintiff, or for a new trial.

The proceedings at the trial are reported in the preceding

case.

Follett, for the plaintiffs. I move to enter a verdict for the plaintiffs in pursuance of leave reserved, or, in case it should be supposed that there was any matter not submitted to the jury in the alternative, for a new trial. There were five pleas, four of which were found for the plaintiffs, and the other, as I submit, was also found for the plaintiffs; but the learned judge directed that the verdict should be entered for the defendants on that issue, with liberty to the plaintiffs to move to enter a verdict for them. I submit

that this is emphatically and exclusively a question for the jury; that it was not a question of law, but of fact, and the jury have distinctly found that the plaintiffs did describe the invention and did point the mode of its use.

The patent was substantially for a mode of heating the air between the blowing apparatus and the furnace in a closed vessel. It was contended, therefore, that every mode of heating the air in a closed vessel between the blowing power and the blast furnace was an infringement of the patent, and the learned judge was of that opinion, and no question arises upon that now. The defendants in this case use a vessel consisting of various pipes, and since the patent was taken out it has been discovered, by various experiments and improvements, that the higher the air is heated the more beneficial its effects on the furnace. That does not seem to have been in the contemplation of the inventor; in the pipes used by the defendants there was greater surface exposed to the fire; it was more economical of fuel, and that vessel consequently produced a higher temperature than vessels of a different kind. The learned judge was clearly of the opinion that it was an infringement[PARKE, B. That it was an improvement, but an infringement]-so long as the patent remained in force.

The question now turns mainly on the fact whether or not the jury did not find the fourth issue in favor of the plaintiffs and two points were made. The objections to be delivered under the statute (5 and 6 Will. IV., c. 83) must distinctly point the attention of the plaintiffs to the precise nature of the objection to be raised. The objection raised was not open to the defendants. The construction put on the plea was not a right construction; but the question is not open because it was for the jury. The finding of the jury that upon the specification alone a person of ordinary skill would construct the apparatus required, disposed of every other question. [PARKE, B. My doubt was whether the evidence of a person of ordinary skill would do, or could be allowed to contradict the grammatical construction of one part of the specification.] The learned judge considered it unnecessary to leave to the jury whether

the particular passage, that the form or shape of the vessel or receptacle was immaterial to the effect, was inaccurate, but he left it to the jury whether it was calculated to mislead, and they found that it was not. The learned judge took that sentence alone from the rest of the specification and stated his opinion to the jury that, in point of law, that was a misstatement, and that it would affect the patent. [PARKE, B. Provided it was untrue in fact.] We have had no opportunity of presenting what has been the impression produced on other minds as to the meaning of the passage. This is not a patent taken out for heating air; that was perfectly well known; and everybody knew that for the purpose of increasing the temperature the larger the surface that was extended to the fire the greater the effect which would be produced on the air within it. The passage does not profess to say that the form and shape of the vessel for heating air is not material as regards the air in those vessels, but that was the construction adopted by the learned judge; and it was in that view that he put it to the jury. I submit that is not the meaning of the passage at all, but that the meaning of the passage is this-I do not make any claim for vessels for heating air. Everybody knows how to heat air, and everybody knows the principle of it. There are various vessels for heating air, of different forms and different shapes, now in use; I say that, as regards the effect on my furnace, the form or shape is immaterial, and may be adapted to local circumstances; and so it is entirely immaterial. It is not immaterial to the heat of the air; and if, upon subsequent discovery, you have found out that by raising the temperature to a higher degree you may improve upon the patent, that is another question; but this patent was never taken out for heating the air, nor has it any reference to the form or shape of the vessel for heating. It is, that when you have heated the air, and heated it for the purpose of raising a stream proper to convey it into the furnace, then the form and shape of the vessel is immaterial as far as regards the working of the blast furnace.

The question as to this passage is for the jury, not for the