J. L. H., of Mo.—We shall be glad to receive your opinions on the two subjects; and should they differ from those ordinarily received, we shall take occasion to make a few remarks thdrcon. J. R-B.,ofN. Y.—A correspondent writes us to inform you that '* Humphrey's Coin-Collectora' Manual,11 published in Bohu's Scientific Library, London, 1853, is the book that will suit you. S. F. R, of Vt.—The Babbitt metal patent will not expire until 1860. The patent is on the mode of confining the metal in the boxes, not on the metal itself. C. W. O' L., of----.—Your mode of constructing railroad trucks by placing the wheels on separatn axles, is quite old. W. II. D.,of Maine.—Appleton &Co., of this city, can furniah you a work on organ-building. Write to them. T. J. McC, of Cullenaburgh, Pa., wishes to know if we are acquainted with a certain concern in this city who deal in lotteries, and if they are men of " right principle." He adds : "I have sent them money, and never got any return for it." Answer.—The firm of whom you inquire we never heard of, and presume in reality it is a myth. We never knew of any person engaging in the lottery business who was of " right principle." If you were so foolish as to send your money to a firm of whom you knew nothing, and especially to purchase lottery tickets, we are glad you have lost it. You probably will not make another investment of the kind at present. T. R. B., Jr., of N. Y.-We do not know who can furnish you with Smith's Patent Perpetual Calendar. E. T., of Iowa.—If you employ a cement of india rubber dissolved in turpentine or naphtha, you can repair your india rubber boots. J. IT., of III.—The swivel wheel attached to the rear end of a cultivator or planter is very common, and you can IUKS the one you have placed to your machine with impunity ; it will infringe no patent. J. L. D., of Texas.—For such machinery as ou inquire concerning, we would recommend you to our advertising columns. No doubt Mr. S. C. Hills would furniah you with a hand lathe of the moat approved Btyle, and perhaps ho would also attend to purchasing such malleable iron castings as you state are needed. Baltzley & Hobson, of Pana, 111., wish to correspond with a manufacturer of knives used in harvesting machines. J. L., of Ky., is correct in supposing fine cork incased hi a bag would make a good life-preserver, but unfortunately he is not the only person that lias made the same discovery. R, M., ofC. W.—The " coffee-mill cut" in rifles is not used on this aide ot the St. Lawrence river, but it is well known to rifle-makers here. The French rifle pistols have the coffee-uull grooves, wliich are triangular. F. G. W.,of Muss.—The strain upon the ends of a steam boiler undoubtedly tends to weaken the transverse plates, as the ruptures by explosions most frequently occur in this direction. You should take into consideration, however, that the pressure of the steam is equal upon every square inch of the boiler; and the strain would also be uniform in every part were it of a globular form. E. U M., of N. Y.—It appears to us that you have taken an hypothesis for a fact. If you had adduced any proof that the moon was once a portion of the earth, and was projected by a Bteam explosion from the bed of the ocean, we might have published your article, but you adduce no proof whatever. F. L., of Ohio.—Your process of tanning Bkins by forming them into Backs, and placing the tanning li.il.uors inside, is not new; the same process haa been practised before. Bark-tanned skins will not color a good cochineal pink. If you employ the chloride of tin and cream of tartar for a mordant, then dye the skins in the cochineal afterwards, you will color them a tolerable pink. There is no work published on this branch of vhe arts. H. B.,ofC. W.— The idea of providing a train of cars with a gasometer, to be filled at the point of starting the train, and to be replenished, if necessary, on the route, from any city gas-works through wliich the train might pasrf, is not new. Neither would the carrying of the gas from one car to another, for illuminating it, be patent-able. But there would necessarily be required some changes in the construction of the gasometer from those in ordinary use, on which a patent might be secured. S. & C, of Me.—Possibly a patent might be secured in your mode of rotating the hook, but the 1'otatiug and reciprocating hook is an infringement of Watson's patent. M. B. Bi, of Texas.—With only two feet of fall on the Guadaloupe river, a common current or tidal wheel U the best you can use. There are no screw wheels in use, although several have been tried. L. G., of 111.—You have won the " wine and cigar?." Our circular is printed. It was originally written with a steel pen and lithographic ink, transferred to stone, and printed. R_ T., of Pa.—The hair dye subject is exhausted. If you have not Cot sufficient information from our columns on this subject, you must apply to sonio other source. CD., of Ohio.—We have given you all the information concerning the steam wagon that we possess at present. J. L., of R. I.—If a manufacturer uses your invention without your consent, you can apply for a patent any time within two years, and after it is issued, you can stop the manufacturerfrom making the article patented. A. J., ofVt—We know of no society of mechanics for 1 the promotion of inventions. The attempt has often been tried to form such an association, but it has never succeeded. A.T. B. of Ohio—From your letter, we infer that you think that power can be obtained by increasing the size of a water wheel, independent of the hight of the fall If this were the case, a low fall could be made to do aa much work as a high one, provided the water wheel was Urge enough. This ia opposed to the well-known laws of mechanics; no power can be gained by increasing the diameter of the wheelfrom twenty to forty feet. We are unable to answer the second question. S. L., of III—Address J. W. Finlay, Editor of the Scottish American Journal, No. Ill Nassau street, this city, and he will supply you with a firflt-rate pair of bagpipes. S. M., of Me.—The placing of a screw propeller in the bow of a boat to draw it. instead of in the stem to push it, is not a practical idea, C. J., of Mass.—The common idea respecting the At-lanticcableis that it must be of sufficient strength to sustain the strain upon it, and that this strain has a tendency to stretch and rupture it. The telegraph cable which you describe aa having been made by you is nearly the same as others which we have seen. E. L.,of Pa,—The adapting of" the ordinary utensils used for cooking in a fire-place to a stovo ia very far from being a patentable idea. Money received at the Scientific American Office on account of Patent Office business, for the week ending Saturday, February 27,1858 :— B. & T., of Mass., $27 ; H. B., of Pa., $30 ; G. P. C. ofN. J.,$57; W. H. L., of Pa., $35; C. II. E., of Mich., $30; A. J. A., of N. J., $30 ; T. W., ofN. Y., $20; W. M. B., of Del., $30 ; A. J. C, of Ind., $25 ; J. H. T., of N. Y., $25 ; A. F. F., of Vt., $27 ; W. C, of Ind., $50; O. P. S., of Me., $10 ; J. H. G., of Ky., $15; P. B., of III.. $30; J. H. B., of Mass., $20 ; T. & S., of Pa,, $20; M. T., of Conn., $30; I. Z. A. W., of Pa., $10; W. F. P., of Pa., $30; J. DeR., of Ohio, $55; M. &B.,of Mich., $30; J. C. A., of Mis*., $55 ; R. II. F., of N. H., $30; M. D., of Conn., $100; G. H., of R. L, $25; J. B., ofN. Y.,$35; G. V. G., of Ohio, $35; W. V., Jr., of N. Y., $55; S. H. G., of Conn., $25 ; G. P. J., of Iowa, $10; H. H. P., of N. Y., $30; J. C, of Ohio, $24; D. H., of Ky., $25 ; I. B. L., of Iud., $10 ; A. B., ofN. Y., $50; R, P., of L. L, $25 ; J. Mel., of N. Y., $25. Specifications and dra wings belonging to parties with the following initials have been forwarded to the Patent Office during the week ending Saturday, February 27,1858 :— A. J. C, of Ind.; J. W. F., of Mo.; B. & T ''l&3B-' K. P., of L. I ,- C. H. E., of Mich.; '? * F- of Vt = G. P- C, of N. J.; G. H., of fc * ! W- F- P- of Pfl- ; R. W-, of-Cann. ; S. H. fS ' Conn.; J. C, of Ohio; D. H.,of Ky.; c. * A., ofN. H.; A. B.,of N. Y.