or action it shall be proved or specially found by the verdict of a jury that any person who shall have obtained Letters Patent for any invention or supposed invention was not the first inventor thereof, or of some part thereof, by reason of some other person or persons having invented or used the same, or some part thereof, before the date of such Letters Patent, or if such patentee or his assigns shall discover that some other person had, unknown to such patentee, invented or used the same, or some part thereof, before the date of such Letters Patent, it shall and may be lawful for such patentee or his assigns to petition his Majesty in Council to confirm the said Letters Patent, or to grant new Letters Patent, the matter of which petition shall be heard before the Judicial Committee of the Privy Council; and such Committee, upon examining the said matter, and being satisfied that such patentee believed himself to be the first and original inventor, and being satisfied that such invention or part thereof had not been publicly and generally used before the date of such first Letters Patent, may report to his Majesty their opinion that the prayer of such petition ought to be complied with, whereupon his Majesty may, if he think fit, grant such prayer; and the said Letters Patent shall be available in law and equity to give to such petitioner the sole right of using, making, and vending such invention as against all persons whatsoever, any law, usage, or custom to the contrary thereof notwithstanding: Provided, that any person opposing such petition shall be entitled to be heard before the said Judicial Committee: Provided also, that any person, party to any former suit or action touching such first Letters Patent, shall be entitled to have notice of such petition before presenting the

same.

III. And be it enacted, that if any action at law or any suit in equity for an account shall be brought in respect of any alleged infringement of such Letters Patent heretofore or hereafter granted, or any scire facias to repeal such Letters Patent, and if a verdict shall pass for the patentee or his assigns, or if a final decree or decretal order shall be made for him or them, upon the merits of the suit, it shall be lawful for the judge before whom such action shall be tried to certify on the record, or the judge who shall make such decree or order to give a certificate under his hand, that the validity of the patent came in question before him, which record or certifi cate being given in evidence in any other suit or action whatever touching such patent, if a verdict shall pass, or decree or decretal order be made, in favour of such patentee or his assigns, he or they shall receive treble costs in such suit or action, to be taxed at three times the taxed costs, unless the judge

making such second or other decree or order, or trying such second or other action, shall certify that he ought not to have such treble costs.

IV. And be it further enacted, that if any person who now hath or shall hereafter obtain any Letters Patent as aforesaid shall advertise in the London Gazette three times, and in three London papers, and three times in some country paper published in the town where or near to which he carried on any manufacture of any thing made according to his specification, or near to or in which he resides in case he carried on no such manufacture, or published in the county where he carries on such manufacture, or where he lives in case there shall not be any paper pub. lished in such town, that he intends to apply to his Majesty in Council for a prolongation of his term of sole using and vending his invention, and shall petition his Majesty in Council to that effect, it shall be lawful for any person to enter a caveat at the Counciloffice; and if his Majesty shall refer the consideration of such petition to the Judicial Committee of the Privy Council, and notice shall first be by him given to any person or persons who shall have entered such caveats, the petitioner shall be heard by his counsel and witnesses to prove his case, and the persons entering caveats shall likewise be heard by their counsel and witnesses; whereupon, and upon hearing and inquiring of the whole matter, the Judicial Committee may report to his Majesty that a further extension of the term in the said Letters Patent should be granted, not exceeding seven years; and his Majesty is hereby authorised and empowered, if he shall think fit, to grant new Letters Patent for the said invention for a term not exceeding seven years after the expiration of the first term, any law, custom, or usage to the contrary in anywise notwithstanding: Provided that no such extension shall be granted if the application by petition shall not be made and prosecuted with effect before the expiration of the term originally granted in such Letters Patent.

V. And be it enacted, that in any action brought against any person for infringing any Letters Patent the defendant on pleading thereto shall give to the plaintiff, and in any scire facias to repeal such Letters Patent the plaintiff shall file with his declaration, a notice of any objections on which he means to rely at the trial of such action, and no objection shall be allowed to be made in behalf of such defendant or plaintiff respectively at such trial unless he prove the objections stated in such notice: Provided always, that it shall and may be lawful for any judge at chambers, on summons served by such defendant or plaintiff on such plaintiff or defendant respectively to show cause why he

should not be allowed to offer other objections whereof notice shall not have been given as aforesaid, to give leave to offer such objections, on such terms as to such judge shall

seem fit.

VI. And be it enacted, that in any action brought for infringing the right granted by any Letters Patent, in taxing the costs thereof regard shall be had to the part of such case which has been proved at the trial, which shall be certified by the judge before whom the same shall be had, and the costs of each part of the case shall be given according as either party has succeeded or failed therein, regard being had to the notice of objections, as well as the counts in the de. claration, and without regard to the general result of the trial.

VII. And be it enacted, that if any person shall write, paint, or print, or mould, cast, or carve, or engrave or stamp, upon` any thing made, used, or sold by him, for the sole making or selling of which he hath not or shall not have obtained Letters Patent, the name or any imitation of the name of any other person who hath or shall have obtained Letters Patent for the sole making and vending of such thing, without leave in writing of such patentee or his assigns, or if any person shall upon such thing, not having been purchased from the patentee or some person who purchased it from or under such patentee, or not having had the license or consent in writing of such patentee or his assigns, write, paint, print, mould, cast, carve, engrave, stamp, or otherwise mark the word "Patent," the words "Letters Patent," or the words " By the King's Patent," or any words of the like kind, meaning, or import, with a view of imitating or counterfeiting the stamp mark or other device of the patentee, or shall in any other manner imitate or counterfeit the stamp or mark or other device of the patentee, he shall for every such offence be liable to a penalty of fifty pounds, to be recovered by action of debt, bill, plaint, process, or information in any of his Majesty's Courts of Record at Westminster or in Ireland, or in the Court of Session in Scotland, one half to his Majesty, his heirs and successors, and the other to any person who shall sue for the same: Provided always, that nothing herein contained shall be construed to extend to subject any person to any penalty in respect of stamping or in any way marking the word" Patent " upon any thing made, for the sole making or vending of which a patent before obtained shall have expired.

ELECTRO-MAGNETIC PRIME MOVER.

Sir, It was with no ordinary pleasure that I read the very interesting account

in your last Number of the Rev. Mr. M'Gauley's Electro-Magnetic Motive Power, which is decidedly the best arrangement hitherto suggested for obtaining motive power by electro-magnetism.

I cannot help noticing, that this successful performance of Mr. M'Gauley, bears a striking resemblance to a speculative attempt to obtain a moving power by means of magnetism alone, which I published in your tenth volume.

The mode of action is, indeed, precisely the same in each, but the reverend gentleman has adopted an infinitely better method of reversing the poles of the magnet, acting on the pendulum, than I had. By this means, all the difficulty of obtaining efficient action is at once entirely obviated, and continuous motion obtained.

I remain, Sir,
Yours respectfully,
W. BADDELEY.

London, Sept. 16, 1835.

THE COMET.

Mr. Editor,-In your 629th Number, Mr. Henderson gives your readers some papers respecting Halley's comet. The path of the comet is acknowledged to have been copied from that in the Nautical Almanac, "with some corrections." What a pity such corrections are not pointed out! In the present improved state of the Nautical Almanac, any corrections must be highly useful and interesting. But is there nothing else copied from the Nautical Almanac ? For my part, I can discover nothing in Mr. Henderson's table that is not copied but its errors-and these are the entire column of meridian altitudes, and the entire omission in the column of declinations of all information as to whether they are north or south, or both or neither; in fact, the whole table (with these exceptions) is copied or rather interpolated (for the dates are ingeniously made different) from that given in the Nautical Almanac for 1833, and again in that for 1835, from which, had it been directly copied into your Magazine without Mr. Henderson's intervention, it would have afforded much more correct information to your readers.

Of the "Remarks" and table which

I trust, Mr. Editor, that you will give insertion to this letter, which is, I assure you, intended not as a reflection upon your Magazine, to which I am, and always have been, a subscriber, but as a check to would-be instructors, who aim at pretension more than at correctness. I, for one of your supporters, do not choose to be ranked amongst a class of readers who require to be told that Ursa Major means the Great Bear. Why did not Mr. Henderson, at the same time, inform us, that it also meant Charles's Wain?

I remain, Mr. Editor,
Your obedient servant,
MOHAWK.

Time of perihelion-1835.

30th of October.

4th of November.

7th of November. .3 17th of November.

Almanac calculation to be correct, or any thing better than an approximation to truth. There is a great share of guessing in all that has been published as to the present comet's appearance, &c. Dr. Fischer, a foreign astronomer, states, that on the 17th November the comet will enter its perihelion; Professor Airy gives the 15th November; Mr. Lubbock, in the Nautical Almanac, gives 30th October; Dr Damoiseau gives the 4th November, and Pontécoulant the 7th November. All these different results arise from different ideas of the extension of the cometary orbit, of the sun's distance from the perihelion and aphelion points, and of the best means of calculating these "datas " The comet was predicted to appear on 7th August (by a telescope); it did not do so for seven or eight days after, and this circumstance gave me an idea of a more expansive orbit than what had been assumed, in which case, of course, more time would be employed in coming to the perihelion I struck an average between Dr. Fischer and Professor Airy, and made out my tables accordingly. The declination and right ascension tables are made out from an estimated

value of the inclination of the cometary orbit; the right ascension from an assumed or calculated velocity given to the comet. The radii vector determines the velocity; the extent or form of the cometary orbit determines the length of the radii vector. As the radii vector increases, the comet's speed diminishes, as it decreases the speed increases, &c.

In my calculation, as published in your Journal, 17th November is mentioned as the day on which the comet enters Gemini. For November read 17th September, with the rest of the reading to the word "rapid."

The comet may be seen to the naked eye about 1st October.

I may mention that the circumference of the orbit of Halley's comet is about 7,250,000,000 miles; length from the aphelion to the perihelion points of its orbit, about 3,500,000,000 miles; the greatest breadth of orbit about 950,000,000 miles; the orbit extends about 1,700,000,000 miles beyond the orbit of the Georgium Sidus; which, therefore, cuts nearly the cometary orbit in equal halves; the nearest approach it makes to the sun may be taken at 56,000,000 miles (English), &c. Dear Sir, Yours truly, E. HENDERSON.

ON

Pall-Mall, Sept. 16, 1835.

FIRE PROOF BUILDINGS. BY MR. CHRISTOPHER DAVY, ARCHITECT.

(In continuation from p. 457.) Experiment 5.-Dec. 6, 1792.

In the front garret of the house, and in the angle of the room, to the right hand of the door (the linings and grounds of which, as well as the floor, were secured), a fierce charcoal fire was made against the linings, at half-past twelve o'clock. At a quarter before two o'clock, the bottom plate of the partition was consumed, and the fire had caught two of the joists underneath, and charred them in a small degree. At ten minutes past two the fire was extinguished, when it appeared that the upper plate of the partition of the story immediately under was on fire; the grounds and linings were consumed about 18 inches high, namely, as high as they were in contact with the fuel; the flame had ascended between the lathing on each side of the partition, and charred

the quarterings, to the top, where it appeared to have been stopped in its course by the plates.

Experiment 6.

On the same day an experiment was made in the back parlour, which was secured so as to resist the strongest fire. The ceiling underneath being plated and plastered, screened dry rubbish was laid three inches deep upon the plating; it was then sound boarded, and filled, lerel with the joists, with rubbish, the plating laid again, and the flooring-boards laid immediately upon it. The floor above was treated in the same manner. The partitions, brick-nogged and plated on each side, were then battened out to receive the lath and plaister; a dado fixed on the partition side of the room, and prepared at the back with Mr. Wood's composition; the jambs, sill, and outside shutter of the window, plated; the door hung and double secured; and the chimney blocked up. As this room was fitted up under the direct superintendence of Mr. Hartley, and his foreman, Mr. Knight, the details contained in the Reports become particularly valuable, and are to the following purport:

An intense fire, which filled the whole of this room, was made, by means of a tar-barrel, pitch-boards, and other equally combustible materials, and regularly fed at intervals during the space of one hour. When the outside shutter was closed, it appeared to affect the flames, so as to abate them considerably; at the same time the plaistering of the ceiling fell, and the inside of the door was consumed, thereby exposing to the flames the plat ing, which, however, remained whole and entire. At half-past two o'clock, the flames appeared on the outside of the door, through the rebate, at the head. At five minutes before three, the shutter was again closed, with a view to extinguish the fire. The smoke appearing through the brickwork, induced the Committee to suppose that the bond-timbers, lintels, and plates, would be consumed. At a quarter past three o'clock, the flames were got under, and the ashes and unconsumed fuel cleared out of the room, when it appeared that the flooring-boards were burnt through, in the seat of the fire, and in other places only charred; the dado was entirely gone; and the battening upon the fire-plates, to which the laths

were nailed, very much charred, as well to the sides as the ceiling. Upon taking off the plating, it appeared that the quarterings of the partition were in a good state, but in a few places the fire had charred them so as to change their colour only. The wood-bricks were also charred half an inch deep; in general, the lintel of the window did not prove to have been injured, nor the door-case; the bottom plates of the partition remained entire; upon removing the boards, the trimmer appeared to have been burnt for a foot in length by half its depth, some others appeared charred only; the adjoining rooms, and the wooden stairs, which were only separated from this room by wooden partitions, were not at all affected during the whole experiment.

Mr. Hartley and Lord Stanhope pro-ceeded with their various experiments in a most enthusiastic manner. Both men of property, as well as men of science, they had a great advantage in this respect over many of their fellow-labourers in the cause of humanity; the experiments were upon that extensive scale that left nothing to be desired.

Having shown in what manner, and with what effect, the energies of Mr. Hartley were directed, I shall in my next enter upon a description of the plan adopted by Lord Stanhope.

C. DAVY, Architect. 3, Furnival's-inn, Sept. 10, 1835. (To be continued.)

FIRE-PROOF BUILDINGS AND THAMES TUNNEL.

Sir,-Having read with much pleasure the observations lately inserted in your Magazine upon the first of these subjects, a full investigation of which is of the most vital importance for public as well as private interest, I beg leave to offer for consideration the following plan; and at the same time would suggest the propriety of enforcing by law any plan for the protection of life and property from fire, particularly in the metropolis, that might be considered efficient.

All party-walls should be 18 inches thick, and all divisions between the front and back part of a house should be nineinch brickwork. The joists should be of iron one inch thick, and drilled through every six inches to receive screws for

fastening down the floor. I would use for the ceilings sheet-iron painted, which would form a perfectly even and durable ceiling, resisting effectually one great means of communication, in cases of fire, between the different stories. Some of the floor-screws might be passed at proper distances through the sheet-iron, the heads being neatly countersunk, and all of them are intended to screw into the underside of the floor, by passing the screw from the lower room. On the top of every house should be placed an iron tank, lined inside with lead, 3lbs. might do, having a ball-cock, and sup.. plied by the Water Companies for domestic purposes as well as in cases of fire. The tanks should be 6 feet square by 3 feet deep, and should be so placed on the roofs, that a communication by a two-inch pipe might be made between each pair of tanks at the bottom. A pipe should descend to the bottom or ground floor and passing through the front wall under the pavement, should be inserted into a general supply three-inch pipe, the latter having at every third or fourth house a pipe two feet long rising from it, and fixed to the wall with a key tap to fix a leathern hose to when necessary, every inhabitant having a key. Such taps would in case of fire supply the engines, supposing only twelve houses formed the side of a street, with nearly eight thousand gallons of water, and the opposite houses of course the same. From the pipe that descends from the tank, should pass to each room an inch branchpipe, having a cock 18 or 20 inches from the floor, with a key fixed to it by a chain. In case of fire breaking out in any apartment, the inmates could speedily put it out, having nearly 1300 gallons of water at their command, the produce of two tanks. I believe that if a proper supply of water were given to the tanks by the companies, those inefficient means for supplying water at fires, viz. turncocks and plugs could be wholly dispensed with. I do not see that it would at all interfere with such an arrangement, if the united tanks were supplied by different companies; nor do I pose there would be any difficulty in supplying the water to the roofs of the houses in London..

sup

The Thames Tunnel speculation ap pears to have excited the angry feelings of many of your contributors; and how