F. D, H., of Ga.—The best way for you to dispose of the invention will be for you to send us your letters patent, and we will get up nice engravings of it and publish in the Scientific American, providing the invention has not been illustrated in any other journal. N. E., of Miss.—Sometime sincere remember reading the notice you refer to, but have not since thought of it. We saw at once the utter stupidity of the affair, and did not deem it worthy of notice. R. A,, ofVa.—In No. 8, of our last volume, we published an engraving of Ericsson's Caloricengine, and expressed our opinion respecting it. Our confidence has not increased a particle since, notwithstanding the steamship which is being built. If it proves better than steam, we shall be ready to acknowledge it. The character of the men engaged in it are, so far as we know, above suspicion. W. WM ofKy.—You seem not to understand the rules wnich govern the conduct of editorswhen the correspondents fail to attach their names to commu nitjations; besides this objection, we would not publish your article for any money—we spurn the idea of receiving pay for inserting articles, and especially where the sentiments are calculated to inflict an unjust injury upon another's interests. H. H., of Conn.—The reason why some people are near-sighted is because the cornea of the eye is so prominent, that the image of distant objects is formed before it reaches the retina, and is therefore not distinctly seen. You will find this subject familiarly illustrated in Brewer's Catechism, designed for pupils. R. E.; of C. W.—Don't send us any Canada stamps, we have no earthly use for them. Send Canada bills, they are good enough. G.E., of Ohio.—We have carefully examined your invention, and find it not patentable. Throckmor-ton's patent on planing machines covers the point claimed in yours. C S. F., of Iowa.—You had better address W. B, Douglas, of Middletown, Conn., for such inform, mation as you require respecting the ram. C. R., of N. 0.—Yours has just come to hand. J. C, of Ohio—Yours will appear next week. J. Cof N. Y.—You have not explained fully the mode by which your cam operates the slide rod. You are aware that the cam is employed on the Mississippi steamboats. We like the link motion, for slide valves. W. W. B., of Md.—We have older records of the Reaper than the one you have sent, *but we are much obliged to you, and will have occasion to use the information at some future time T. J. A., of 111.—Simply attaching weights to the sails of wind-mills could not be made the subject matter of a patent. "W. D. B., of Mass.—Your device for rolling metal we think is new and patentable. A. M, of Vt.—A. Small's patent, of 1848, covers yoi^ your invention, therefore you cannot obtain a patent. J. P A., of Ky.—The stuff for keeping the polished iron parts of a steam engine bright, is oil, and frequent rubbing up, nothing else. You can keep polished iron bright, by using copal varnish; put on a thin coat. This varnish, we suppose, you can get in any drug store in Louisville. W- M., of N. Y.—Yours is not a patentable subject —if you published a book you could copyright the plan and tables, or you could bopyright the tables. The discovery is a philosophical principle, for which a patent could not be obtained. S. E., of N. Y —The article l Effects of Steam on Timber," which, you see going the rounds of some papers, as original, is taken, word for word, from an old article in the Sci. Am. T. H. R , of Ala,—Francis Wolle, of Bethlehem, Pa-, is the inventor of a machine for making paper bags, you would do well to address him for a description, or you willprobably see it illustrated in the Sci. Am. some time during the present volume. H. 0. R., of N. Y.—The work upon telegraphs is in our library, you can examine it at any time ; it is in the French language. S-S. B., of Ta.—There is no such rule as the one you speak of, for calculating the horse power of a water wheel by its size. An overshot wheel 20 feet in diameter if it is propelled by 6 cubic feet of water per second, is only 9 1-10 horse power; if it consumes 20 cubic feet per second it is a little over 30 horse power. The power of a fall is according to its height, and the quantity of water discharged in a given time. Multiply the height in feet by the number of cubic feet discharged per minute, that by 62 1 2, and divide by 33,000, and you have the nominal horse power; the actual will be more than 25 per cent. less. R. C, of Ct —Tisitors at the fair of the American Institute are pouring in from all parts of the country. The exhibition is worth your attention as there are many improvements in railroad enginery and apparatus. R. E.,ofPa.—We have delayed our answer to your inquiry respecting the brake until we could examine the one you refer to. We find the model on Exhibition at the Fair embraces the same arrangement, precisely, as yours, but you need not be alarmed for neither of them are new. We find that the same device was patented in 1847. G-. H. J)., of Ct.—It is singular that so old an inventor—one who has taken out so many patents — should not have discoveredearlier that such claims \ were good fornothing. 0. C. L., of Mass.—Yours will be answered at a very early date. R. V., ofKy.—Your plan for an improved brick press appears to be good ; it is patentable. R, R., of N. Y.—Your communication will be attended to in due season, Tfcou see the right point. Z. S D., of Mass.—The thoroughly dried sawdust should protect wrought iron; we have never, seen it tried, but believe it will answer; charcoal dust will do it. S. A. Lj, of S. 0.—You have been effectually anticipated in your ideaB, for the truth of this see number 48, last volume. This, you see, contradicts the statements that you have " read the Scientific American carefully for two years, and it contains nothing like it." F. B. H., of Ind.—Before we received your letter of the 1st inst., we had transmitted your specification ond drawings to the Patent Office, therefore you will be obliged to wait the issue of the patent before having an engraving appear in our columns. We think a patent will be issued, but cannot tell when. Tell your friend that his carriage wheel is old. Take our advice and remain easy until you learn the result of your present application before putting more "irons in the fire." You have ingenuity, take care and not confuse it by too many ideas. Your letter we will preserve for further reference. Money received on account of Patent Office business for the week ending Saturday, Oct. 9:— L N. L,,of Mass., $30. D. S., of N, H., $45 ; R. H. T., of 8. C , $300 ; F. J. P., of N. Y,, $20 ; J. E , of R. L, $10 ; R. L , of N. Y., $55 ; E. Tan C, of Pa., $5 , R. C. B , of 111., $200 ; J. S., of Miss., $30; G. B. D., of Mass. $30 ; A. M., of Pa,, $35 ; J. B. A., of S. C, $55 ; J. G. P., of R. I., $30; L. B. B., of Vt., $25 ; M. E., of—, $40 ; F. B., of N. Y., $58 ; E. L, G., of N. X, $30 ; a R., of N. Y., $20 , C. W. G , of N. Y., $20 : C. .. of N. Y., $60 : E. M., of N. Y., $30 : H, L,, of Ct., $25 ; C. W.C., of Ohio, $25. Specifications and drawings belonging to parties with the following initials have been forwarded to the Patent Office during the week ending Saturday, Oct. 9 : A. F. P., of Mass.: D. S., of N. H. ; J. G-, of N. Y.; J.J., of N. J. ; J. E., of R. I; S. R., of N. Y.; L. B., of Vt ; M. DeLaC^of Spain; F. C. G., of N. Y., {2 cases).