paddle-wheels, by preventing the concussion incidental to them on entering the water, and causing the floats to rise therefrom in such a manner, that they lift but comparatively little back water, and therefore do not produce so much swell in the wake of the vessel. The principle on which he constructs his wheel is that of the cycloidal curve; and in illustration, proceeds to state, that if we conceive a vessel going at a certain speed, and a circle as a, fig. 1, in the accompanying diagram, travelling with that vessel, and making a

Fig.1

certain number of revolutions in a given time, the circumference of that circle, multiplied by the number of revolutions, will give the distance, in admeasurement, that the vessel has passed over in the same time. We may, therefore, imagine this circle rolling on the hori zontal b, c, (the water line on which the vessel floats); and if a point as d, be taken upon the circle a, and supposing it to start from e, and rolled along the horizontal line b, c, the curve e, d, will be traced by that point, which will be a perfect cycloid; and if the circle a, be of such circumference that its speed is equal to

the velocity of the vessel, a curved bar fitted to this cycloidal curve would be completely immersed in water, it constantly entering at the point e. Then, suppose the generating circle a, to be the boundary of the inward edges of the floats and the circle e, f, that of the outward edges, the wheel then reduced to practice will bear the form represented at fig. 2.

Fig. 2411 03

To the cycloidal curve d, e, Mr. Galloway's floatboards are attached by any of the ordinary means. These floats, instead of being constructed in broad sheets in the usual manner, are divided into narrow separate boards. It should be here remarked, that the surfaces of the floats must be calculated as if they were on the ordinary principle, according to the power, number of strokes of the engine, and the velocity required. The floats are placed in direct radial lines from the centre, and it will readily be perceived, that very little more water will be displaced in their revolution, than that disturbed by the entrance of the first float.

The Patentee further states, that although he prefers constructing his paddle-wheels under the circumstances before mentioned, yet that advantage cannot always be conveniently obtained; for supposing the circle e, to be twice the diameter of a, it is evident that a cycloidal curve, to pass through the point d, would extend considerably further (say to h,) in the outer circle: under such circumstances, the float-boards would be a great distance apart, which he has found to be a serious defect. In this case he prefers using an approximation to the cycloidal curve, for he believes that any direction of floats, even confined to a straight line, will be an improvement on the ordinary plan, if such direction forms an angle less than d, e, to d, i, which is the ordinary line of the floats; and if the floats be mounted on a curve or a straight line, having an angle less than that of d, i, to d, h, he conceives he will not be departing from the limits of his claim of invention.

The Patentee concludes by remarking, "that since the sealing of his patent, he has been informed that Mr. Field, engineer, of Lambeth, employed paddle-wheels formed by detached narrow float-boards in a steamvessel called the Endeavour;" a drawing of which he has exhibited in his specification, to point out the difference. (A figure of this drawing will be found in our number of December, 1835, Plate X., No. 2.) Mr. Galloway states that this wheel is entirely different from the subject of his present patent, and that he does not intend to claim the mounting of the float-boards in detached parts, unless confined to the principles laid down in his present specification..-[Inrolled in the Inrolment Office, February, 1835.]

In the number of our Journal above alluded to, will be found a communication from Mr. Joshua Field, in

which he has shown three modes of mounting the floats of paddle-wheels on the cycloidal principle, as used by Messrs. Maudsley, Son, and Field, and submitted by them to the Lords of the Admiralty in the years 1833 and 1835. For our parts, we cannot see the difference between the two constructions. Mr. Galloway's invention appears to be a distinction without a difference; for we can conceive no point in that gentleman's specification that will not be amply anticipated by all competent persons on reading the communication from Mr. Field. ED.

SCIENTIFIC ADJUDICATION.

CORNISH AND ANOTHER, V. KEENE AND ANOTHER. This was an action arising out of an application in the Rolls Court, for an injunction to restrain the defendants from manufacturing certain elastic fabrics, for which Mr. Sievier, one of the plaintiffs, obtained letters patent on the 17th of January, 1833: a great number of affidavits had been filed by the parties in the Rolls contradictory of each other; and an action was undertaken to be brought by the plaintiffs, on the defendants being required to keep an account. The cause came on in the Common Pleas, before Lord Chief Justice Tindal and a special jury, on the 7th of December last. The plaintiffs' case was conducted by the Attorney-General, Mr. Sergeant Wilde, Mr. Sergeant Stephens, and Mr. Hindmarsh. The defendants, by Sir F. Pollock, Mr. Creswell, and Mr. Knowles.

The patent which the plaintiffs obtained, was specified on the 17th of June, 1834; the details of which will be found in vol. iii. p. 65, Conjoined Series, of our

Journal. The defendants, it was alleged, infringed the patent right of the plaintiffs by copying one of the objects of the specification (the third). Evidence was adduced by the plaintiffs, to prove the manufacture and sale of an imitation of the patent article by the defendants.

The pleas put on the record by the defendants were1st. That they were not guilty of an infringement of the patent.

2d. That the Patentee was not the first inventor.

3d. That the invention or discovery itself, at the time the patent was granted, was not a new invention, as to the public use and exercise thereof in England.

4th. That it was not an improvement in the making or manufacturing elastic goods or fabrics.

5th. That there was no sufficient specification.

A number of persons were brought by the defendants to sustain their third plea only. We need offer no remark on their evidence, beyond that after a prolonged and searching investigation of two days and a half, the jury returned a verdict for the plaintiffs.

Since the trial, Sir F. Pollock has obtained a rule nisi to move for a nonsuit, on two grounds.

1st. That to apply a known material made in a known manner, to effect a known object, cannot be the subject of a patent.

2d. That the mode of effecting one of the objects of the patent is distinctly pointed out in the specification of a previous patent obtained by Mr. Sievier, in 1831; and for a new trial on two grounds.

1st. That the verdict was against evidence.

2d. That since the trial, fresh evidence has been dis. covered in the specification of a patent, dated 14th November, 1832.