Mr. Morgan in practice makes his rods of different lengths, and
he must necessarily do that in order that the floats may follow
at the same angle as the driving float enters the water.
If so,
he should have said in his specification, "I make my rods of
different lengths, in order that the rest of my floats may enter at
the same angle; and the way to do that is so and so.” Or he
might have said, " it may be determined so and so." But the
specification is totally silent on the subject; therefore, a person
reading the specification, would never dream that the other floats
must be governed by rods of unequal length; and least of all
could he ascertain what their lengths should be, until he had
made experiments. Therefore it is contended that the specifi-
cation does not state as it should have stated, the proper man-
ner of doing it. He says, if they are made of equal lengths,
though the governing rod would be vertical at the time of enter-
ing, and three would be so when they arrived at the same spot,
by reason of the operation Mr. Park suggests, yet the fourth
would not come vertical at the proper point, nor would the fifth,
sixth, or seventh. Then they would not accomplish that advan-
tage which professes to be acquired. The patentee ought to
state in his specification the precise way of doing it. If it can-
not completely be done by following the specification, then a
person will not infringe the patent by doing it. If this were an
infringement, it would be an infringement to do that perfectly
which, according to the specification, requires something else to
be done to make it perfect. If that be correct, you would pre-
vent a man from having a perfect engine. He says, practically
speaking the difference in the length of the rods would not be
very material, the difference being small. But the whole ques-
tion is small, therefore it ought to have been specified; and if it
could not be ascertained fully, it should have been so stated.
Now this is the part to which I was referring, when in the pre-
liminary observations I addressed to you I cited the case before
Lord Mansfield, on the subject of the introduction of tallow to
enable the machine to work more smoothly. There it was held
that the use of the tallow ought to have been stated in the spe-
cification. This small adjustment of these different lengths may
have been made for the purpose of making the machine work
more smoothly; if so, it is just as much necessary that it should
be so stated in the specification, as it was that the tallow should
be mentioned. The true criterion is this,-has the specification
substantially complied with that which the public has a right to
require? Has the patentee communicated to the public the
manner of carrying his invention into effect? If he has, and if
he has given to the public all the knowledge he had himself, he
has done that which he ought to have done, and which the pub-
lic has a right to require from him.

I will now read the defendant's evidence, and you will see A. D. 1836. whether upon the whole there is evidence before you on which you think you can come to any reasonable conclusion.

evidence.

Now first of all, Mr. Donkin, a man of considerable experi- Defendant's ence, is called; but before I go to his evidence, I will remark, that I have always found that there is a great deal of contradiction in questions of this description; but that is not to be attributed in the least degree to corruption, or to any intention to misrepresent or mislead-people's opinions vary. They come to state to you not matters of fact, but matters of opinion, and they tell you conscientiously what their opinion really is. You may have a great difference of opinion among scientific men on a question relating to science; but though by their evidence they contradict one another, they are not influenced by a corrupt desire to misrepresent (g).

Now Mr. Donkin says, "On first reading the specification, I thought there was a defect in its not explaining the mode of obtaining the required angle. In my judgment, a workman of ordinary skill would not be able to find out any mode of obtaining the required angle." He says, a geometrician might discover the mode of adjusting the three angles, the angle of immersion, the vertical angle, and the angle of emersion; but in order to discover the mode by which all the paddles may enter at the sime angle, another discovery must be made. He says, it requires to be ascertained by experiment or diagram, whether the adjustment is to be made by altering the bent stem, or by varying the length of the rods, and you have nothing but the drawing to guide you in that respect. He says, he must first ascertain whether he is to produce the effect by altering the centre, or by altering the bent stem, or varying the lengths of the moveable rods. What are those but experiments to ascertain how the thing should be done, all of which he ought to have been saved by its being stated in the specification how to do it. However, that is his evidence; he says, the angle must depend on the dimensions of the several parts of the wheel. Then he goes on to the other parts of the case, and on his cross-examination he says, "I think a competent workman would be able to do it if he made the previous discovery; but he would not do it unless

(g) The learned judge here adverted to a case alluded to by Sir F. Pollock, in which the question was as to the point at which oil would boil (probably the celebrated case of Severn v. Olive), and ren a ked that both parties were of the same mind when they made their experiments upon the same data, but they had not made the same experiments. They had not taken into consideration, he believed, the difference between the effect of heat applied to oil in the course of a long time, and the effect upon oil when heat was applied only for a short time. Time was left out of their consideration,

and that appears to explain all the difference that existed between them. The ultimate result was, that there was not any difficulty in determining the point; but the court decided that case upon this ground: they said, " ten men are of opinion there was no danger of the house being burned by this operation, and ten are of opinion that there was danger;" was it not fair that the insurers should have known of it, that they might have determined the question for themselves? That was the point on which the court decided, rejecting the evidence on both sides.

Allerson, B., to the jury.

a careful investigation was gone into." He says, "few ordinary workmen would be able to get the desired angle; I think my foreman would-I think a person moderately acquainted with geometry might do it, but he must find it out-he could sit down and determine it. If he possessed proper information, he ought to be able to do it. An engineer properly skilled in geometry, ought to be able to find out how the angle was to be determined. If he sat down and referred to his general knowledge, he would find it out." Now the criterion is not whether he could find it out or not, but whether he could do it by means of the information contained in this specification and drawing, calling in aid his general knowledge, and those mechanical means with which he may reasonably be expected to be familiar; but if he is to sit down and consider how it is to be done, that is not sufficient. You will judge whether or not the evidence of this witness satisfies you on these points, and whether it makes out the proposition for which the defendants contend.

Then Mr. Brunton says, "I think a workman of competent skill could not construct a machine so as to have the floats enter at any particular angle, and leave at a particular angle." He says, if the required angle was different from the drawing, it would be an exceedingly difficult thing, and he is not prepared to say how he could do it. Then Mr. Hawkins says, "I do not think a workman of ordinary skill could, from the plan and specification, make a wheel that should enter and quit the water at a different angle from that given in the drawing, unless he possessed considerable ingenuity for inventing the method of doing it."

Then Mr. Peter Barlow says, "There are not, I think, sufficient data to adjust the angle." He says, if the length of the stems was given, the difficulty would be very great, but it would have been a guide, and it ought to have been explained. That appears to me to be a very good common sense observation. Then Mr. John Donkin says, "I think an ordinary workman would find considerable difficulty in altering a paddle wheel to suit a particular angle, and I doubt whether he could do it." On his cross-examination, he says, "it requires more than a common knowledge of geometry; I think a man moderately acquainted with geometry might do it, but he would have to make experiments, and his first experiments would fail. A skilful engineer would have less difficulty in it, but he ought to be able to find it out." Then Mr. Bramah says, "I think I could discover how to do it." He has been an engineer many years, and he says, “I think I could discover it, but I do not know at present how to do it. Yesterday I attended to the evidence, and this morning I tried to find out how it was to be done, but I could not." Supposing Mr. Bramah had to make a machine of this kind, is he to sit down and invent a mode of doing it, or ought he not to have such information afforded as would enable him to do it at once

by means of the specification? Then Mr. Francis Bramah says, A. D. 1836. "I have examined the specification: I could not make a machine from the specification, the floats of which should enter and leave the water at any required angle. Till I came into court yesterday, I presumed that the angle given in the drawing was the best angle, that is, that the specification had not only stated how to do it, but had described the best angle." If so, it would be a specification only for that particular angle. He says, "I can go as far as I was told yesterday, but no farther."

Now, gentlemen, I have gone through the evidence on both sides, on this point, and the question upon this part of the case resolves itself into this: Do the witnesses on the plaintiffs' side satisfy you that the patentee has, in his specification, given to the public the means of making a machine which shall enter and leave the water at any angle that may be ordered; that is, if a man ordered a machine at an angle likely to be required for entering and going out, and to be vertical at the bottom, could an ordinary workman with competent skill execute that order by The specificafollowing the directions given in this specification? If you think if a workman by he could, then the specification would be sufficient. If, on the following the other hand, you think he would not be able to execute the order unless he sat down and taxed his invention to find out a method order. of doing that which has not been sufficiently described in the specification, then the specification would be bad. If you think the specification good, then you ought to find for the plaintiff's upon that issue; if you think the specification bad, then you ought to find for the defendants.

tion is sufficient,

directions could

execute an

With respect to the steam engine, the question will be, whe- An invention not getting into ther the machine is of use. On that subject the evidence on one general use, a side is, that the steam engine is useful in various ways. Mr. Bru- presumption nel does not state it to be of very great use, but the other wit- against its utility. nesses speak of its packing in a small compass, and consuming less fuel, and they say that it is in some respects more smooth and even in its movement. The witnesses for the defendants say that they have examined it, and do not think it of any use. The fact on which the defendants rely in addition is, that though this invention took place in the year 1829, no engines were constructed upon this principle, except one of two or three horse power, which was employed in the plaintiffs' own manufactory, and which, according to their witnesses, was useful and worked well. There was another of about six or eight horse power, worked by Mr. Morgan, and afterwards sold, but which undoubtedly was not used by the persons to whom it was sold,or if it had been we should have had some evidence of it. It was no doubt only used while it was in Mr. Morgan's factory. Then there is evidence of a third, which was put on board a steamer, which appears not to have been much used, for one of the piston rods broke, and therefore the engine failed. That circumstance

Alderson, B., to the jury.

It is sufficient if an invention be

would not show the engine to be of no use; but the circumstance of its not being supplied, and not getting into general use, is a circumstance for you to take into your consideration.

The first question in this case will be, whether you think the new, and of any steam engine was a useful invention. If it was of any use. [Jer

use.

Verdict.

vis: Whether it was an improvement on former steam engines, my lord.] I think not. I think if it was of a different construction from any other steam engine, and of any use to the public, then that is sufficient. If you, gentlemen, should be satisfied that the steam engine is of no use, you ought to find your verdict on that issue for the defendants, and then, though you may be of opinion that the paddle wheels are useful, still if persons will be so foolish as to put two inventions into one patent, one of which is good and the other bad, they lose the benefit of their patent till the Attorney General allows them to strike out that part which is invalid, and gives them the protection of the patent for the valid invention. But that applies to the future, and not to the past.

Gentlemen, these are the facts of the case. It is for you to consider, first, whether the specification has fairly and fully disclosed the nature of the invention, and the mode of carrying it into effect. If you think it has, you will find that issue for the plaintiffs; if you think not, your verdict ought to be for the defendants.

Then the second question will be, whether you think the steam engine is a useful invention. If you think it is a useful invention, you will find for the plaintiffs; if not, for the defendants. [A Juror: Suppose it is worse than the former, my lord.] Then it would be of no use. If it could be used where other steam engines would not answer, though it would not be likely to come into general use, it would be less useful, but still it would be of some use.

Verdict for the plaintiffs, on the issues on the first, second and fourth pleas; and for the defendants, on the issues on the third, fifth and sixth pleas. Leave to move to enter the verdict for the plaintiffs on the fifth plea.

In the Exchequer.

Mich. T. 1836.

In the ensuing term the plaintiffs obtained a rule, calling on the defendants to show cause, First, why judgment should not Plaintiffs' rule. be entered for the plaintiffs, non obstante veredicto, on the third issue; Secondly, why the verdict for the defendants on the fifth issue, should not be set aside, and a verdict entered for the plaintiffs (c); Thirdly, why the finding of the jury on the sixth

(c) At the trial, the learned judge directed a verdict for the defendants on this issue. The following was the evidence :

In the month of February, 1829, one Curtis, a

machine maker at Bermondsey, began to make for Morgan, the plaintiff, in his (Curtis's) manufactory, two pair of paddle wheels on the principle for which the patent was afterwards taken out, receiving