H. B., Jr., of Canada.—We can give you no information as to where the "Tinsmith's Guide" can be obtained. R. C, of-Ky.—We are not disposed to furnish receipts for making rum or any other kinds of spirituous liquors C. C, Jr., of Masa."No; the water which discharges through pipe No. 6 of your contrivance will not drive a wheel with sufficient power to pump fluid enough to keep the machine perpetually in motion. The reason is the same as that which prevents you from lifting yourself over a picket fence by simply drawing upon the seat of your pants. S. J. L., of Conn.—You inquire if ** a patent prohibits any one from making the invention for his own use." We have frequently answered an inquiry of this character in our columns, but we have no objection to a repetition if we can thereby enlighten any of our readers. A patent confers upon the patentee the exclusive right to make, use, and sell his invention. He can also allow the same rights to others; but it would be a punishable infringement of his patent for any one, without his authority, to make and use for their own private purpose, or sell to others to uso, the patented invention. Z. E. C, of Conn.—It will be safe to have your lightning rod terminate in the well, notwithstanding the fact that there are iron pump pipes extending to the house. Upward discharges of electricity have been known; but the fluid has never been known to discharge downward, and then run right back again to the clouds. If it were to do so in the case suggested it would follow the rod, because that would be a better conductor than the house. The greater the quantity of conducting material at the base of the rod, communicating with the earth, the better. Tho electric fluid is thereby spread over a larger surface, and passes off more readily. The water and pump pipes will therefore assist the discharge of the electrical fluid. It will make no difference whether the rod and pipes are in contact. We should prefer to have them in contact, because the metal is a better conductor than the water. Water will conduct electricity from one point to another, or from one conductor to another. These facts have before been given in our paper, though not in this precise form. G. P., of Mass.—A good distance indicator for carriages would take well, we think. C S., of Pa.—For the tubing and the information you ask, apply at any of the rubber stores in your city. H. M., of Conn.—Get Manser's ice-cream freezer, at New Haven, Conn. G. W. II., of N. Y.—Your communication upon the sundial is very interesting, but we have no room for its insertion at present. K E., of N. Y.—The oil of mustard is obtainedjay expressing the seed. Any sirup may be. made, which will keep without alcohol, by simply expressing the juice from the fruit andboiling with sugar, and excluding the air from the vessel in which it is contained. W. A. H., Jr., of R. I.—A solution of alum applied to the cloth will render it impervious to water for a long time, andwill not mildew. A. H. L., of Wis.—Sulphuric, not muriatic acid, is employed to bite worn fil.s. Use one part (by measure) of the acid to seven parts of water, and place the filesvertically in the liquor thus made. They should be thoroughly cleansed in soap suds from oil and grease, before being put into the acid. Steep them in the acid for half an hour, then wash them well in hot water, and they are fit for use. J. B. M, of 111.—On page 380, Vol. 6, Soi. AM., you will find an engraving of a self-regulating flood gate. The patent was issued November, 1849, to S. D. Hopkins, ofBrookville,Va. " Old Subscriber" seems to be ignorant of the nature of kerosene and camphene, so far as it regards their non-explosive character. The frequent accidents which take place by the explosion of lamps are not caused by camphene, as you seem to suppose, but a composition of camphene and alcohol. E., of N. Y.—Your surmises that some one has been to the Patent Office and exerted an influence unfavorable to your case, are wholly unfounded. The Commissioner would not tolerate, for a moment, any such interference. Depend upon it, in our hands, your case is safe, and every possible thing will be done to secure your rights. No action has yet been reported, and we presume its time for examination has not arrived. A. C, of N. J.—It is said that the Chinese poBsess the secret of rendering copper hard enough to make edge tools, but we western barbarians do not know how it is done. A correspondent wishes to know what kind of cement is used for fastening block letters for signs on' stone or brick. Can some subscriber inform him? Money received at the Scientific American Office on account of Patent Office business, for the week ending Saturday, July 10,1858 :— J. M. E., of N. Y, $55 ; A. S., of N. Y, $30 ; E. T. L., of Ala., $14; A. F. R, of III., $30 ; E. B.,ofN. Y., $15; W. AH.,ofN.Y.,$30; J. D., of N. Y.,$30; H. T. C, of N. O, $30 ; A. S., of Pa., $25; A. N. McE., of Mo., $30 ; G. W. B., of N. Y, $55 ; A. S. S., of Ohio, $30; F. B.,of Conn., $30; C. &S., of L. I., $25; D. &K., of N. Y., $30 ; P. W. G., of 111., $50 ; J. M, of Ga., $250; F. C.,of N. Y.,$25; U. T. S.,of Tenn.,$25: F. B. A., of Iowa, $55; A G. D., of Conn., $30 ; H. L, A., of Wis., $30 ; L. W., of Mich., $25 ; L. &D.,' of N. Y., $30; J. J. S., of Mass,, $35; T. H.,of Ohio, $30; J. L. F,, of Texas, $65; A. W., of L. I., $25; R. W., of Vt, $30; B. B. S., of 111., $25; P. S. C, of 111., $30; J. &J. f\ J. C, of N. Y., $25 ; F. McN., of Ohio, $30 ; F. K., of 'A N. Y., $30 ; J. N. L., of N. Y., $25: J. B., of Conn., if $155 : J. S^ of Ohio, $30 ; K. R, of Wis., $30 ; C. S. ?-, of Conn., $30 ; J. A. T., of Ohio, $25; P. D., of N. pcJY., $25. Specifications and dra wings belonging to parties with the following initials have been forwarded to the Patent Office during the week ending Saturday, July 10,1858 :— J. N. L., of N. Y. ; J. &J. C. H., of N. Y.; C. &S., of L. I.; J. J. S., of Mass. ; L. W., of Mich. : J. M E., of N. Y.; E.M. S.,ofN. Y.; U.T. S.,of Tenn. ; J. J. P., of Ohio ; A, W., of L. I.; J. M., of N. Y. ; J. D. S., of Ohio; E. T. L., of Ala. ; B. B. S., of 111. ; F. C, of N. Y.; A. S., of Pa.; S. B. S., of Mo. Literary Notices HUNT'S MERCHANTS' MAGAZINE for July contains, in addition to the usual amount of valuable matter, a likeness and biography of Lieut. General Sir William Pepperrell, Barf.—the only native American ennobled by the British government for services rendered America. It is published at 142 Fulton street, N. Y. GOOD BREAD, WITHOUT YEAST OR POWDER. Published by W. Hunt. 18 and 20 La Grange place. Boa-ton. Price 10 and 15 cents.—This little work contains some healthy, practical, careful receipts, and some common sense advice on ventilation, diet, c. THE ECLECTIC MAGAZINE OP FOREIGN LITERATURE. W. H. Bidwell, 5 Beekman street. New York.—This number for July contains some excellent articles. The one entitled **The Beautiful in Nature, Art and Life," from Titan, strikes us as the best.
This article was originally published with the title "Correspondents"