D.D. S., of Conn.—We are not acquainted with what you want; but it appears to us that it would be ho difficult matter to gear a loom to accomplish your object. J. D. C., of Pa —Your self-acting Fire Alarm is essentially the same as one described in volume 3, of this journal; Invented by Messrs. Tomlinson&Hopkins, of Conn. J. J. S , of N. Y.—We cannot furnish the Information about the matter which you desire. E.D. W., of Montreal. -We are not acquainted with a better publication upon Drawing than Mini- fie's work. Chapman's book, when finished, will be an excellent work; but he is now abroad and will not complete it for some time to come. J. S. Red- field, of this city, has published three or four numbers. H.A. B., of Brooklyn,—The person on the car in motion It makes no matter how swift he is capable of jumping, he must do so along with the train, or he will find it difficult to pick himself up afterwards . W. H., of Mass.—It makes no matter if a man has obtained a patent, he cannot prevent you from employing the same process, if that process is old and well-known. If it has been in use in a foreign country, the patent can be sustained, if it has never been patented, or published; but if it has, in either case it will nullify the patent. To be upheld by law a patent must be for a “ new and useful” invention. We will look up the cases with which you are very intelligently acquainted. J. C., of Ohio.—We will do as you have requested. Your opinion about the Hillotype, corresponds with our own. We have never seen a statement made' by any one who had seen the whole process. D. C., of Me.—Your's will receive attention. C. W. F., of Me.—Your's is under consideration. A. W.T., of Mass.—Brass tubing is made from sheet metal, by cutting up the sheet in long strips and bending them round a central coil or mandril,whose thicknes equals the intended internal diameter of the pipe' The two opposite edges are made to lap over each other, and in that state are soldered together. When soldered, the tube is cleaned and brightened by means of dilute acid, and is then ready for drawing. The drawing is effected by a mandril being passed through the tube, which is drawn forcibly through a circle smaller than its external diameter, and being pressed closely on every side, its internal and externalgsurfaee become regular and smooth. J. J., of Pa.—Your's will receive attention. The question had nothing to do with momentum, merely the revolution, as we stated; if the small wheels slide over its surface, in everyrevolution, how much does it roll the whole revolution which will make it to describe a. line a.s long as the largQ wheats. H- L ., of Ga.—Gutta Percha is hardened by mixing it with black lead. It can be obtained in this city, of Armstrong&Co., “ the Gutta Percha Co." A. A., of Md.—You might, perhaps, sell youreagle to Barnum, if it is a good specimen; but you would not earn a day's board by exhibiting it here three mon'hs. The rent of Castle Garden is about $100 per day; so you can calculate yourself what the probable chances would be for making monsy in exhibiting your eagle at that place, as you suggest. J. B. C., of Tenn.—Our opinions are unchanged. The force of the artisan did not cease before the effect was produced; but his effort did. If you call a. medium which carries the force, inertia, then. you are right; but we do not view it in this light. ''Inertia is that quality of matter by which it is inca pable of spontaneous change.” This is the best definition of it, if it is a resisting quality, than it is active, and very badly named; and should be called the law of “repulsion." Money received on account of Patent Office business for the week ending Saturday. Nov. 20:— A. H. B., of N. Y, $200 ; G. W. W., of N. Y., $30; W. C ., of Conn., $20 ; B. F C., of N. Y., $30; C. F” B1 of R. I. , $20 ; S. K , of N. Y., $30; G. P., of N . Y., $20 ; J. E. A , of Ct, $20 ; H. B. G., of N. H., $25 ; D.&L. C., of Conn., $25. Specifications an. drawings belonging to parties with the following initials have been forwarded to the Patent Office during the week ending Saturday, Nov. 20: J. B. A., of Pa. ; R.&S., of Pa.; W. C., of Conn,; H. A .. of N. Y. . C. F. B., of R. I. ; J. C , of N. Y. ; J. L. B , of Ohio ; T. M ., of Pa. ; J. E. A., of Conn. ; H. B. G., of N. H.; D.&L. C., of Conn.; W. G. H., of Pa.
This article was originally published with the title "To Correspondents"