the described effect; which concealment or addition shall fully appear to have been made for the purpose of deceiving the public, or that the [patentee was not the original and first inventor or discoverer of the] thing patented, or of a substantial or material part thereof claimed as new, or that it had been described in some public work anterior to the supposed discovery thereof by the patentee, or had been in public use, or on sale with the consent and allowance of the patentee before his application for a patent, or that he had surreptitiously or unjustly obtained the patent for that which was, in fact, invented or discovered by another, who was using reasonable diligence in adapting and perfecting the same; or that the patentee, if an alien at the time the patent was granted, had failed and neglected for the space of eighteen months from the date of the patent, to put [in operation and use in the United States] and continue on sale to the public, on reasonable terms, the invention or discovery for which the patent was issued [or in case the same, for any period of eighteen months after it shall have been put in operation and use, shall cease to be so used or put on sale], in either of which cases judgment shall be rendered for the defendant, with costs. And whenever the defendant relies in his defence on the fact of a previous invention, knowledge, or use of the thing patented, he shall state, in his notice of special matter, the names and places of residence of those whom he intends to prove to have possessed a prior knowledge of the thing, and where the same had been used: Provided, however, that whenever it shall satisfactorily appear that the patentee, at the time of making his application for the patent, believed himself to be the first inventor or discoverer of the thing patented, the same shall not be held to be void on account of the invention or discorery or any part thereof having been before known or used in any foreign country, it not appearing that the same or any substantial part thereof had before been patented or descrived in any printed publication. And provided, also, that whenever the plaintiff shall fail to sustain his action on the ground that in his specification of claim is embraced more than that of which he was the first inventor, if it shall appear that the defendant had used or violated any part of the invention justly and truly specified and claimed as new, it shall be in the power of the court to adjudge and award as to costs as may appear to be just and equitable.

Sec. 16. And be it further enacted, That whenever there shall be two interfering patents, or whenever a patent on application shall have been refused on an adverse deci. sion of a board of examiners, on the ground that the patent applied for would interfere

with an unexpired patent previously granted, any person interested in any such patent, either by assignment or otherwise, in the one case, and any such applicant in the other case, may have remedy by bill in equity; and the court having cognizance thereof, on notice to adverse parties and other due proceedings had, may adjudge and declare either the patents void in the whole or in part, or inoperative and invalid in any particular part or portion of the United States, according to the interest which the parties to such suit may possess in the patent or the inventions patented, and may also adjudge that such applicant is entitled, according to the principles and provisions of this Act, to have and receive a patent for his invention, as specified in his claim, or for any part thereof, as the fact of priority of right or invention, shall in any such case be made to appear. And such adjudication, if it be in favour of the right of such applicant, shall authorise the Commissioner to issue such patent, on his filing a copy of the adjudication, and otherwise complying with the requisitions of this Act. Provided, however, that no such judgment or adjudication shall affect the rights of any person except the parties to the action and those deriving title from or under them subsequent to the rendition of such judgment.

[Section 17 unaltered. section is entirely new.]

The following

Sec. 18. And be it further enacted, That whenever any patentee of an invention or discovery shall desire an extension of his patent beyond the term of its limitation, he may make application therefore in writing to the Commissioner of the Patenl-office, setting forth the grounds thereof; and the Commissioner shall, on the applicant's paying the sum of forty dollars to the credit of the Treasury, as in the case of an original application for a patent, cuuse to be published, in one or more of the principal newspapers in the city of Washington, and in such other paper or papers as he may deem proper, published in the section of country most interested adversely to the extension of the patent, a notice of such application, and of the time and place when and where the same will be considered, that any person may appear and show cause why the extension should not be granted. And the Secretary of State, the Commissioner of the Patent-office, and the Solicitor of the Treasury, shall constitute a board to hear and decide upon the evidence produced before them both for and against the extension, and shall sit for that purpose at the time and place designated in the pub lished notice thereof. The patentee shall furnish to said board a statement, in writing, under oath, of the ascertained value of the invention, and of his receipts and ex

penditures, sufficiently in detail to exhibit a true and faithful account of loss and profit in any manner accruing to him from and by reason of said invention. And if, upon a hearing of the matter, it shall appear to the full and entire satisfaction of said board, having due regard to the public interest therein, that it is just and proper that the term of the patent should be extended, by reason of the patentee, without neglect or fault on his part, having failed to obtain, from the use and sale of his invention, a reasonable remuneration for the time, ingenuity, and expense bestowed upon the same, and the introduction thereof into use, it shall be the duty of the Commissioner to renew and extend the patent, by making a certifi cate thereon of such extension, for the term of seven years, from and after the expiration of the first term; which certificate, with a certificate of said board of their judgment and opinion as aforesaid, shall be entered on record in the Patent-office; and thereupon the said patent shall have the same effect in law as though it had been originally granted for the term of twenty-one years. And the benefit of such renewal shall extend to assignees and grantees of the right to use the thing patented, to the extent of their respective interest therein: Provided, howerer, that no extension of a patent shall be granted after the expiration of the term for which it was originally issued.

Sec. 19 [18]. And be it further enacted, That there shall be provided for the use of said office, a library of scientific works and periodical publications, both foreign and American, calculated to facilitate the discharge of the duties hereby required of the chief officers therein, to be purchased under the direction of the Committee of the Library of Congress. And the sum of fifteen hundred dollars is hereby appropriated for that purpose, to be paid out of the patent fund.

[Section 20 unaltered.j

Secs. 21 [20]. And be it further enacted, That all Acts and parts of Acts heretofore passed on this subject, be, and the same are hereby repeated: Provided, however, That all actions and processes in law or equity sued out prior to the passage of this Act, may be prosecuted to final judgment and execution, in the same manner as though this Aet had not been passed, excepting and saving the application to any such action, of the provisions of the fourteenth and fifteenth sections of this Act, so far as they may be applicable thereto. And provided, also, That all applications or petitions for patents, pending at the time of the passage of this Act, in cases where the duty has been paid, shall be

Sir, The annexed drawing is a section of an universal centre-punch, which was contrived by me four years ago; but I have since been told that others have previously invented the same thing, which, from its extreme simplicity, is highly probable. Be this as it may, I have found it of great use in centering pieces of iron, &c. for turning between points in the lathe, or for finding a lost centre, and I therefore think it worthy of being more generally known, as will be seen from the drawing; it is merely a hollow cone terminating at the point in a small tube, which tube contains á cylindrical steel punch, fitting it accu rately, and which is truly in the centre

of the cone; the cone is of iron. From its construction, it will immediately be seen that any piece of iron, &c., square, round, triangular, or of almost any shape, and of various sizes, may be in an instant centered by merely placing the instrument upon it and striking the punch. To insure accuracy in making the instrument, I may state that I used the following method:-Having first roughly turned a piece of iron externally into the shape required for the body of the in

strumen, I fixed it firmly by the small end in a chuck; I then drilled a hole directly through it-the larger end of the instrument running in a boring collarthis hole was then turned as far as necessary into a cone; a clearing bit was then passed through the hole to form the tube for the punch, which bit and purch were made from the same piece of drawn polished steel wire.

N. S. HEINEKEN.

Sidmouth, Nov. 17, 1836.

upon the mandril; into the under part of the slide of the eccentric chuck is screwed a round pin, which passes through a slit in the foundation plate of the eccentric chuck, and is a little longer than the three rose wheels sent. The usual traversing screw of the eccentric chuck being removed, its slide will be free to move backwards and forwards. Now upon the above-named round pin is placed the small ivory rubber-wheel e, and which is contained between two thin plates or flanges of brass. This wheel is placed, at pleasure, upon any of the rose wheels; its brass flanges preventing it from shifting; a spring acting against the slide of the eccentric chuck keeps the rubber-wheel in contact with the rose wheels, and the lathe being put in motion, the figures will be produced by the usual application of the tools, in the slide rest, to the work. These figures might be made to assume an oval form also, by allowing the frame of rose wheels to be so fixed to the lathe as that they should be eccentric to the mandril. The position of the curves also may be varied by turning round the division plate of the eccentric chuck. The patterns produced by this contrivance differ from the roseengine patterns in being at opposite points reversed, and in diminishing in curvature as the slide of the eccentric in its revolutions assumes a vertical position; thus, by simple means, adding a variety to the ornamental parts of the lathe.

Should the above be deemed of service, it will give me pleasure to forward, occasionally, descriptions of some other mechanical contrivances relating to the lathe, and other apparatus.

to philosophers several centuries before the christian era. Nothing further, however, than this simple fact, seems to have been ascertained for the space of two thousand

years.

The first modern experiments upon record were those of Dr. Gilbert, of Colchester, an account of which he published about the year 1600, in a Treatise de Magnete. Although several philosophers repeated the experiments of Gilbert, and somewhat augmented the list of electric substances, no discovery of importance was effected until about the year 1670, at which period Otto Guericke, celebrated as the inventor of the air-pump, constructed the first electrical machine of which we have any account, and acquired an additional title to renown, by discovering the light and sound by which the electric fluid is accompanied.

The existence of electric light was observed shortly afterwards in England, by Dr. Wall, to whom also is due the honour of first suggesting the idea of a resemblance between electricity and lightning..

This resemblance was afterwards noticed by Mr. Stephen Gray, who flourished about the year 1730; and still later by the Abbe Nollet; but neither of them appears to have attempted any investigation of the subject. The complete solution of this interesting problem in electrical science was reserved for our venerated countryman, Franklin; who, at an early period of his investigations, be came strongly impressed with the idea that lightning and electricity were identical. He accordingly drew up a statement of the principal points of resemblance between them, and suggested a plan for proving the truth of his theory, by elevating pointed conductors upon a lofty tower or spire. This paper, together with several others upon the same subject, he transmitted to his friend Mr. Collinson, of London, by whom they were communicated to the Royal Society.

The reception which these essays met with in that learned body was by no means flattering, as will be perceived from the following extract from Franklin's Memoirs:-" Obliged, as we were to Mr. Collinson, for the present of the tube, &c, I thought it right he should be informed of our success in using it, and wrote him several letters containing accounts of our experiments. He got them read in the Royal Society, where they were not at first thought worthy of so much notice as to be printed among their transactions. One paper which I wrote for Mr. Kinnersly, on the sameness of lightning and electricity, was read, but was laughed at by the connoiseurs." The papers being afterwards shown to Dr. Fothergill, he thought them of too much importance to be stifled, and advised the printing of them. They were

accordingly published in a pamphlet form by Cave, a bookseller in London, with a preface by Dr. Fothergill. A copy of this pamphlet happening to fall in the hands of Buffon the naturalist, this eminent philosopher was so well satisfied of the justness of Franklin's views, that he determined on making the attempt to draw down lightning from the clouds. Accordingly, he raised an insulated rod of iron upon the tower of Montbar, and prevailed upon M. D'Alibard to prepare an apparatus for the same purpose at Marly La Ville, about six miles from Paris. This ap-. paratus consisted of a pointed iron rod, about forty feet long and an inch in diameter, the lower extremity of which was brought into a sentry box, and insulated upon a table with glass feet. M. D'Alibard entrusted the charge of his apparatus to a man named Coiffier, who, having served fourteen years in the dragoons, was supposed to have sufficient courage for such an undertaking.

We have been thus particular in our description of this machine, because it was the first to receive a visit from the ethereal fire; and shall now proceed to give a narrative of that important event, extracted from a paper laid before the Royal Academy of Science, at Paris, three days after the occurrence. "On Wednesday, the 10th of May, 1752, between two and three o'clock in the afternoon, M. Coiffier, an old dragoon, whom I had entrusted to make observations in my absence, hearing a pretty loud clap of thunder, immediately flies to the machine, taking with him a vial in which was fixed a brass wire; on presenting the point of the wire to the rod, he sees a small brilliant spark issue from it, and hears a crackling noise; he takes a second spark stronger than the first, and with á louder noise! He calls his neighbours, and sends for M. Roulet, the Prior of Marly. The Prior runs with all his might, and the parishioners seeing his haste, imagine that poor Coiffier had been killed by the thunder; the alarm spread throughout the village, and the hail which succeeded did not prevent them from following their pastor.

"The honest ecclesiastic arrived at the machine, and seeing there was no danger tries the experiment himself, and takes some strong sparks. The hail storm was not more than a quarter of an hour in passing the zenith of our machine, and there was no more thunder after the first clap." As soon as the cloud had passed, and they could get no more sparks from the rod, the Prior despatched M. Coiffier with the following hasty letter:

"1 announce to you, sir, the fulfilment of your expectations; the experiment is complete. This day at twenty minutes after two in the afternoon, it thundered directly over Marly, the clap was pretty loud. The desire

to please you, and curiosity, induced me at once to quit my arm chair, in which I was engaged reading. I was hastening to M. Coiffier, and met on the road a child whom he had despatched to call me, I redoubled my speed through a terrent of hail. Arriving at the spot where the rod was placed, I took a brass wire, and advancing it towards the rod, when within about an inch and a half, a small column of blueish flame with a smell like sulphur, sprung with wonderful quickness to the point of the wire, and occasioned a noise as if the rod had been struck with a key. I repeated the experiment at least six times in about five minutes, each experiment requiring about the time of a Pater and an Ave. I wished to continue them, but the action of the fire gradually abated, and at length ceased altogether. The stroke of thunder which had occasioned this event was not followed by any other, and the whole was terminated by a copious shower of hail.

"I was so engaged during the experiment, that receiving a blow upon my arm above the elbow, I could not tell whether it proceeded from the brass wire or the rod. I did not complain at the moment, but the pain continuing on returning home, I uncovered my arm in the presence of Coiffier, and we perceived a contusion around it, such as would be caused by a blow from the wire upon the bare skin. When returning with Coiffier, I met the curate, M. de Milley, and the school. master, to whom I reported what had happened. They all three perceived a smell of sulphur, which increased as they approached me: this odour was also perceived by the servants before I said any thing to them about it.

"You have here, sir, a hasty recital, but it is correct and true, and I assure you that I am ready to testify to these facts on all occasions. Coiffier was the first to make the experiment, and he repeated it several times before he sent for me. If any other testimony besides his and mine is necessary, you can obtain it. Coiffier is in haste to depart. I am yours with respectful consideration, "RAULET, Prior of Marly.

"May 10, 1753."

Immediately upon the announcement of M. D'Alibard's success, M. Delor, demonstrator of physic, at Paris, erected a bar of iron upon his dwelling for the purpose of repeating the experiment, and succeeded in procuring several sparks during a thunderstorm on the 18th day of May. On the 19th of the same month, Buffon obtained a similar result at Montbar.

Thus was Franklin's hypothesis verified in Europe, while its illustrious author was waiting for the erection of a spire at Philadelphia, by which he should be enabled to reach what