WE are often annoyed by the receipt of letters, very properly done in all respects, with the exception that the Post-office address is omitted. We have two on hand now to which we are anxious to reply: one from James Graves, the other from Cloud & Hatfield. We are often censured for neglect which is wholly cbargable to our correspondents, in the manner above indicated. Correspondents should not only write their names in a clear and unmistakable manner, but also give Post-office directions in full—town, county, and State. G. T. and others, of Conn.—You ought to be aware that it would require a considerable amount of printing space, illustrated with engravings, to give you the desired information regarding the arrangement of parts in a beam engine, and the construction of eccentrics. You will find the desired information in " Hodge on the Steam Engine," or " Tredgold. " T.B, J., of Mass.—We are much obliged to you for the useful information you have forwarded to us. E. T. Q., of Mass.—Your idea of allowing the warm air to circulate under the floor to warm the lower part of a building or apartment, is an excellent one, though not new. In the plan of warming and ventilating patented by II. Ruttati, 1843, the air is admitted to the upper part of the apartment, and after making its escape sjj the bottom, pasacs under the whole of the floor. By this plan not only is the floor warmed from below, but a downward circulation of the warm air is obtained, by which a unifprmity of temperature in the upper and lower parts of a room ia insured, and all the dust is con- * fined to the floor. J. C. S., of Ohio.—The oil of rhodium is made from rhodium wood by distillation, and is chiefly brought from the Levant. J, R. B,, of N. Y.—We do not know where you can obtain an illustrated work on old coins. In Addison's works there is an excellent illustrated treatise on old medals. W. A. M., of Ohio.—There are a great number of patents on combined corn planters and cultivators. You arc aa liable, if you make a machine for your own use which infringes upon an existing patent, as if you made and sold it to another to be used. J. P., of Mich.—Your remittance of $15 to payforen-graving your ore-waaher, came safely to hand. D. D. C, of N. Y.—If you have an order to build an improved machine, and furnish it to other parties, it does not prevent you from securing a valid patent for it afterwards. It must not, however, be publicly used for more than two years prior to the application. L. P. S., of Conn.—The arrangement which you have made in the magneto-electric machine, by presenting the same poles of the magnet to the same ends of the helix, i3 not an improvement, but the reverse. Each pole of the magnet must be successively brought near to either end of the helix, to magnetize the soft iron of the armature with opposite polarity. This ia the way we understand the action of the magneto-electric machine. You can easily try an experiment, and satisfy yourself. W. S. R., of Ohio.—li" you boil ground glass, or fine white sand, ia a strong solution of cauatic soda, you will obtain the soluble silicate of soda. You can make the caustic ley by adding fresh slacked lime—half and half—to the soda solution. Use the clear liquor for dissolving the glass. J. A., of Ohio.—The pressure on a slide valve of the construction commonly used in the steam engine is as the whole area of the valve, if the face fits perfectly steam tight to its seat. J. R., of N. Y__The article on back-lash in grist mills, in our last number, contains all the information you desire. C. A. C, of Pa.—Wire rope ia not so strong as bar iron of the same diameter, but we do not know the exact difference. A good wire rope, four inches in diameter, and six feet long, has sustained a strain of 29 tuns. We do not know anything more about Cornwall & Brothers than that they paid for their advertisement. S. P., of N. J.—Roman cement, clean sand, and some linseed oil boiled with coal tar to the proper consistency makes a very good cement for the roofs of outhouses. Its surface should bo covered with sand or fine gravel. See an excellent article on cements on page 306, Vol 11, Sei. AM. F. G. W., of Mass.—You ask, "Will the cohesiveness of iron be impaired in one direction by its beingsubject-ed to a separating force at right angles to that direction?" Certainly it will. It mii3t rupture in that direction, and no other. J. T. & Co., of Me.— India rubber buttonsare manufactured exclusively by one company, under the Goodyear patent. We do not know the exact proportions of the materials employed in their composition, but shell lac the carbonate of magnesia, andlamplackare mixed with the india-rubber. J. A. B., of Minn.—Throw eome potatoes or Indian corn meal into your boiler, which will stop the lenks in its seams. We have also seen horso manure used successfully for the same purpose. A good cement for iron joints is made with two ounces of sal ammoniac, one of sulphur, and sixteen of cast iron filings pounded in a mortar and made into a thick paste with water. It is packed into the seams of the boiler with a chisel or knife, and allowed to stand for two or three days until it dries. It ultimately becomes as hard as the metal itself. F. T., of Minn.__We are unacquainted with any substance that will restore gray hair to its natural color. We advise you not to try anything for this purpose. Cultivate your health, do good continually, and snap * your fingers at those who despise gray hairs. The ni-J trte of silver, 20 grains, dissolved in an ounce of soft h water and a little ammonia, will dye white hair a dark |& brown color. J. L. M., of Texas.—Your project of reclaiming the land now covered by the Gulf of Mexico is gigantic and splendid, but have you taken into account the immense capital required for building the wall before the waters can be pumpad out ? Here is the greatest and most difficult work. Instead of employing small 20-inch pumps, we would use pumpa of 100-inch caliber. J. W. of N. Y.—Saws have been "so set and filed" as to saw and plane at the same time. CD., oflll.—Hail ia not produced by the meeting of two clouds or currents of air, but rain is produced in thia way, and frozen into hail by passing afterwards through a colder stratum of air. We do not think you can apply the same principles artificially to a meat safe. There are railroad cara now used for bringing carcaseaf rom the West to our city, which carcasses are cooled artificially by ice and evaporation. C. L. P., of Ya.—The arms of wooden axles for wagons are made very slightly conical in form, and with a strip of iron flush with the wood on the upper and under sides ; this renders them stronger, and more durable. A carriage with low wheels can be drawn up a steep hill with greater ease than one with high wheels, because the relative gravity of the wagon iaia-creaaed with the incline of the plane. J. A S,, of N. Y.—Make the secondary coil of your helix one-fourth the length of your primary coil. Some have employed primary and secondary coils of the same length. J. R-, of Pa.—We do not think a patent has ever been granted for a quilting machine. Some of our ingenious inventors are, no doubt, capable ot inventing such a machine. C. C, of Pa.—We think there is sufficient encouragement to warrant an application for a patent on your bullet-moldiug machine. You had better not delay your application. We have aeen the sadresults of such delays so often in our experience that we cannot advise a postponement. Money received at the Scientific American Office on account of Patent Office business, for the weekending Saturday, February 13,1858 :— J. SI., of R. I, $25; J. G. B., of N. J., $3; D. H., of Ky., $30; S. & W., of Wis., $30 ; R B. W., of N. II., $50; T. A. D.,ofN. Y.,$25; A. H. G.,of Ind., $30 ; J. J., of S. C, $30; B. Y., of N. Y., $55 ; W. A. S., of Mass., $30 ; G. T., of N. Y., $55 ; H. B., of N. Y., $05 ; A. &Bro's., of Conn., $30; E. S., of La., $30; L. J., of Mass., $25; J. R.,ofN. Y.,$10; J.II.,ofN. Y.pi; D. O. DeW.,of N. Y., $30; G. II, of K. L, $30: J. Mel., of N. Y., $30 ; A, M., of N. Y., $30 ; IL M., of N. Y., $90 ; R. P., of L. I., $30 ; J. L. R., ot S. C, $30 ; W. Y. G., of Ky., $30 ; I1' S. H., of Conn., $25; II. G. B., of Mich., $30; W. & I .1)., of Conn., $30; C. W. H., of Mass., $30 ; A. R, of N. V., $20 ; & C, of N. Y., $30 ; G. L. D., of N. Y., 32 ; J. L. It., of N. Y., $27. Specifications and dra ivings belonging to parties with the following initials have been forwarded to the Patent Office during the week ending Saturday, February 13,1858 :— A. S.,of N. Y. ; J.'P. M.,of B.L ; J. J.,ofS. C. ; L. J.,ofMass. ; K. Bro's., of Mass. ; S.C.,ofN.Y.; J. G. B., of N. J. ; E. S. S., of Conn. ; E. R. B.,of Conn. ; G. L. D., of N. Y. ; J. L. It, of N. Y. Literary Notices A DIOTIONAKY OF MEDIOAI. SCIENCB.—By Robley Dunglison, M D., L. L. D. Blanchard & Lea, Philadelphia.—A new edition of this valuable book has just appeared, having aboutsix thousand new subjects and terras added, and tiie whole has been carefully revised. This is one of the most gigantic works that was ever produced by a singlo individual, and under each medical word or term will be found exactly the information the medical man or technologist requires. It is a most valuablecontribution to the number of lexicons at present extant IMPERIAL CTOLOP-EDIA OF MACHTEST—Parts 11 and 12 of thia truly imperial production have just been issued by C. B. Russell & Bros., Tremont street, Boston. They contain excellent drawings of one of Stephenson's express locomotives ; warping machinery for factories ; screw propellers, and their engines. This publication ia got up in a superior manner. MUSPHATT'S CHEMISTRY—Parts 33 and 34 of this admirable work have just been published by C. B. Russell & Bros., of Boston. They containa full treatise on the manufacture ofglass in all its branches. It is got up in excellent style, and deserves an extensive patronage. WE have received the ATLANTIC MONTHLY for February, containing several interesting articles by distinguished authors. To Our Subscribers RECEIPTS—When money is paid at the office for subscriptions, a receipt for it will always be given; but when subscribers remit their money by mail, they may consider the arrival of the first paper a bonafide acknowledgment of the receipt of their funds. llie Post Office law does not allow publishers to enclose receipts in the paper. BACK NUJUHEHS.—After the 1st of January, we shall commence sending the SCIENTIFIC AMERICAN to new subscribers from the time their names are received, unless the person ordering expresses a desire to receive the back numbers, in which case complete sets will be furnished from the commencement of the volume. Important to Inventors AMERICAN AND FOREIGN PATENT A. SOLICITORS.—Messrs. MUNN & CO., Proprietors of the SCIENTIFIC AMEEIOAN, continue to procure patents for inventors in the United States and all foreign countries on the most liberal terms. Our experience ia of twelve years' standing, and our facilities are un-equaled by any other agency in the world. The long experience we nave had in preparing specifications and drawings has rendered ua perfectly conversant with the mode of doing busmes3 at the United States Patent Officej and with most of the inventions which have been patented. Information concerning the patentability of inventions is freely given, without eharge, on sending a model or drawing and description to this office. Consultation may be had with the firm, between nine and four o'clock, daily, at their principal office. 128 Fulton street, New York. We have lately established a Branch Agency on the corner of F. and Seventh streets, Washington (opposite the United States Patent Office). This office is under the general superintendence of one of the firm, and is in daily communication with the Principal Office in New York, and personal attention will be given at the Patent Office to all such cases as may require it. We are very extensively engaged in the preparation and seeming of patents in the various European countries. For the- transaction of this business we have offices at No s. 66 Chancery Lane, London ; 29 Boulevard Saint Marti n, Paris ; and S Rue Therraienne, Brussels. We think we may safely say tbiit three-fonrths of all the European patents secured to American citizens are procured through our Agency. Circulars of information concerning the proper course to be pursued in obtaining patents through our Agency, tlie requirements of the Patent Office, &c, may be had gratis upon application at the principal office or either of the branche. Communications and remittances should be addressed to MUNN & COMPANY, No. 128 Fulton street, New York. The annexed letter from the late Commissioner of Patents we commend to the perusal of all persons interested in obtaining patents :— MESSRS. MONN & Co—I take pleasure in stating that while I held the office of Commissioner of Patents, MOEE TIIAN ONE-KOUKTII OF ALI. TIIE BUSINESS OP TUB OFFICE came through your hands. I have no doubt that the public confidence thus indicated has beeu fully deserved, as I Have always observed, in all your intercourse with the Office, a marked degree of promptness, skill, and fidelity to the interests of your employers. Yours, very truly, CHAS. MASON. PAPER MILL FOB. SALE, OK TO MEASE —The subscribers offer for pale or to rent their Mill, situated in North Bennington, Vt,, and on the railroad, thirty mile east of Troy, N. Y. Said mill was built four years ago, is novr running, in complete order, and has all the fixtures tor making hanging, printing or book paper. To may one wishing to purchase, it will be sold w, and terms of payment made easy. A large portion ot' the nioney_ can remain on bond &ad mortgage. For further particulars address the subscribers at North BenniDgton, Vt. THTCHEB & WELLING. TWO VALUABLE PATENTS FOE SALE OR Exchange—Call he sold in every family. One costsCOcenta, sellsfor $3 50; the other, 10 cents, sells for 20. Address, (with stamp,) 13. BURNS OLCOTT, New York City. TptJRKEY YELPERS—A TURKEY CALL OF Jl my own make and pattern can be mailed to any State in the Union by enclosing $1 to S. SUTHERLAND, Gun-maker, Richmond, Ya. NOW IS THE TIME TO PURCHASE ONE-fourth of the patent right of a machine for $1,000 cash, which will realize a fortune, an*will prove no failure. Machinists could do with less cash capital. Such an opportunity rarely occurs. Address A. B. FLITCRAFT, No. 314 Union street, Philadelphia, Pa. ANOTHER WONDER—BALDWIN'S TUR-bine Water Wheel (represented in No. 51, Volume XII, Soi. AM. ,) gives from 75to97percentof power, according to the size of wheel and head employed. Usual sizes, with 4 to 25 feet fall, give 80 to 90 per cent. For information address S. K. BALDWIN, Laconia, N. H. SOD CORN ? PLANTERS—PERSONS WISH-ing to purchase territory or aa interest in my Sod Corn Planter, (which was patented January 26,1858,) can address me at Homer, Champaign county. 111. P. C. MOSIER. SWISS DRAWING INSTRUMENTS — A full stock of these celebrated instruments always on hand. Catalogue, 4th edition, with 25.0 illustrations of Mathematical, Optical and Philosophical instruments, and attachment of illustrated sheet representing the Swiss instruments in the actual size and shape, win be delivered, on application, to all parts of the United States, by sending 12 cents in postage stamps. Address C. T. A1SLER, 635 Chestnut at, Philadelphia, Fa. LD. JONES & CO., WESTERN PATENT . Right and Machinery Exchange, 44 North Second st., St. Louis. Mo. Agents for the purchase, saie, and exhibition of patent rights, patented machinery, &c. OCtTJIRE'S SELF-DISCHARGVGTlii C5 RAKE—Patented December 27, 1856. Themost simple, durable, effectual, and only labor-saving rake invented. Rights for sale. Send for a circular. JOHN J. SQUIRE, Bunker Hill, 111. ARTESIAN WELLS—THE SUBSCRIBER IS -ii. engaged in compiling information relating to Artesian Wella, and respectfully requests of parties throughout the United States who Uave bored, or are boring for water, (or who propose to do so,) that they will communicate with him, giving, so far as they are willing, detailed statements of their progress and success, the mode of boring, implements used, strata encountered, depth reached, character, flow and temperature of water, with the amount of labor and expense incurred, difficulties met with or surmounted, and any other item of interest Parties who make it their business to bore for water or explore for minerals, aro requested to furnish their address. T. H. LEAVITT, No. 1 Change avenue, Boston, Mass. WOODWORTH PLANERS—IRON FRAMES, to plane 18 to24 inches wide—at $90 to 110. For sale by S, G HILLS, 12 Platt street, New York. WOODWORTH IMPROVED—TWO GOLD Medals have been awarded to me for my patented improvements upon the celebrated Woodworth Planing Machine. The above awards, and the large number of theBe machines now in operation, fully demonstrate their great superiority over all others. Machines of all sizes constantly for sale. JAMES A. WOODBURY, 69 Sudbury st., Boston, Mass. BOILER FLUES —ALL SIZES, AND ANY length desired, promptly furnished by JAMES O. MOBSE & CO., 79 John St., New York. "PORTABLE STEAM ENGINES. —S. C. X HILLS, 12 Platt street, New York, offers for sale these Engines, with Boilers, Pumps, Heaters, etc., all complete, suitable for printers, carpenters, farmers, planters, &c. A 2K horse can be seen in store ; it occupies a space 5 by 3 feet; weight, 1,500 lbs. ; price $240. Other sizes in proportion. ------------- ) I? FORBES, ARTIST, 89 NASSAU STREET, -CJ. New York, Mechanical and General Draughtsman on Wood, Stone, &c. WROUGHT IRON PIPE—PLAIN AND GAL-vanied, sold at wholesale by JAMES O. MORSE & CO., 79 John st.. New York. STEAM ENGINES, STEAM BOILERS, Steam Pumps. Saw an Grist Mills, Marble Mille, Rice Mills, Quartz "Mills for jold quartz, Sugar Mills, Water Wheels, Shafting and Pulleys. The largest assortment of the above la the country, kept constantly on hand by WM. BUKDON, 102 Front treet, Brooklyn, HARRISON'S 30 INCH GKAIN MILLS-Latest Patent.—A supply constantly on hand. Price $200. Address New Haven Manufacturing Co., New Haven, Conn. WARP KNITTING LOOMS FOR SALE— Three or four warp knitting Looms, suitable for weaving Peatfield's double and single Bay State jackets, Gurnsey frocks, shirts, drawers, and fancywarp-work in general. For particulars, inquire of JAMES PEAT-FIELD, Ipswich, Mass. CM. CRESSON'S CELLULAR GAS RE- TORT—Patented October 3, 1864—adapted to the manufacture of gas from wood, and other vegetable substances, and now in use at the Philadelphia Gas Works. Patent rights for sale. For information apply to HENRY S. HAGERT, attorney for patentee, at the south-east corner of Walnut and Sixth sts., Philadelphia, Pa. ALCOTTS CONCENTRIC LATHE-THIS Lathe i s capable of turnln g under 2 inches in diameter with only the trouble of changing the dies and patterns to the size wanted. It will turn smooth over swells or depressions of % to the inch, and works as smoothly as on a straight line, and does excellent work. Price S25, (without frames,) boxed, and shipped with directions for setting up. For sale by MUNN & CO., 128 Fulton street, New York City. JECOND-HAND MACHINISTS' TOOI.S- K7 Consisting of 20 Engine Lathe, 9 Iron Planers, 4 Upright Drills, Hand Lathes, Chuck Lathe, Gear Cutters and Vices, all in good order, and for sale low for cash. For particulars, address FRANKLIN SKINNEl 14Whitneyavenue, New Haven, Conn. STEAM PUMPS, BOILER FEED PUMPS, Stop Valves, Oil Cups, Cocks, Steam and Water GageB, sold by JAMES O. MORSE & CO., No. 79 John street, New York. TVIACHINE BELTING, STEAM PACKING, 1~1 ENGINE HOSE.—The superiority of these articles, manufactured of vulcanized rubber, is established. Every belt will be warranted superior to leather, at one-third less price. The Steam Packing is made in every variety, andwarranted to stand 800 clegs, of heat. The hoae never needs oiling, and is w:irranted to stand any required pressure ; together with all varieties of rubber adapted to mechanical purposes. Directions, prices, &c, can be obtained by mail or otherwise, at our warehouse. NEW YORK BELTING AND PACKING COMPANY. JOHN H. CHEEVER, Treasurer, No. 6 Dey street, New York. NEW HAVEN MANUFACTURING CO.— Machinists' Tools, Iron Planera, Engine and Hand Lathes, Drls, Boit Cutters, Gear Cutters, ftuekg, &c*, on hand aad finishing. These tools are of superior quality, asd are for sale low for cash or approved paper. For cuts giving full description and price, address "Mew Haven Manuiacturiog Co., New Haven, Conn.' ENGRAVING ON WOOD AND MECHANICAL DRAWING, by RICHARD TEN EYCK, Jr., 128 Fulton street. New York, Engraver to the Scientific American. WOODWORTH PLANING MACHINES— Having over $40,000 worth now completed, I will sell, from this time henceforth, at a very reduced price, and am ready to construct any sizes not on hand at short notice. JOHN H. LESTER, 57 Pearl st., Brooklyn, Long Island. LAP-WELDED IRON BOILER TUBES-Prosaer's Patent.—Every article necessary to drill the tube-plates and set the tubes in the best manner. THOS. PROSSER & SON, 28 Platt st., New York. SAWS.—HOE&CO.'SPATENTGROUND SAWS PlastermgTrowels,&c, can be had, wholesale and retail, at the principal hardware stores, at the. salesrooms of the manufacturers, 29 and 31 Gold stree t, or at the works corner of Broome, Sheriff and Columbia sts.. New York. Illustrated catalogues, containing prices . and information interesting to sawyers generally, will be sent by post on application. LEME—PAGE'S PERPETUAL KILN-PAT-ented July, 1857. Superior to any in use for wood orcoal. 234 cordsof wood, or IX tuns of coal to 100 bis. —coal not mixed with stone. Address C. D. PAGE, Rochester, N. Y. WELCH Sc GRIFFITHS-ESTABLISHED 1830—Manufacturers of Improved Patent Ground and Warranted Extra Fine Cast Steel Saws, of the various kinds now in use in the different sections-f the United States and the Canadas, and consisting of the celebrated Circular Saw, Graduated Cross Cut and Tenon, Gang, Mill, Pit, Segment, Billet and Felloe Saws, &c., &Q. For sale at their warehouse. No. 48 Congress street, Boston, Mass. OIL! Olli! OIL!-FOR RAILROADS, STEAMERS, and for machinery and burning. Pease's Improved Machinery and Burning Oil will save fifty per cent., and will not gum. This oil possesses qualities vitally essential for lubricating and burning, and found in no other oil. It is offered to the public upon the most reliable, thorough and practical test. Our most skillful engineers and machinists pronounce it superior and cheaper than any other, and the only oil that is in all caBeB reliable and will not gum. The Scientific American, alter several tests, pronounced it " superior to any other they have ever used for machinery." For sale only by the inventor and manufacturer, F. S. PEASE, 61 Main st., Buffalo, N. Y. N. B.—Reliableordersfilledforany part of the United States and Europe. E'XCELSIOR STEAM PUMPS, DIRECT i and Double-Acting, manufactured and sold at 55 and 57 First St., Williamsburgh, N. Y., and 301 Pearl st., New York. May be seen in operation at J. O. Morse & Co., 79 John St., New York, GUILD, GAEKISON & CO. VAIL'S. SPEEDWELL IRON WORKS, Morristown, N. J., manufacture Craig's Patent Double-acting Balance Valve Oscillating Steam Engines both stationary and portable, Knowles' Patent Muley, Portable, Gang and Re-sawing Mills, Sugar and Chinese ' Cane Mills and Sugar Pans, Grist Mills, Mill Irons, Rich's Water-wheels, Forgings and Castings. Orders 1 for the above, and all descriptions of labor-saving ma- { chinery will receive prompt attention. ; JOHN H. LIDGERWOOD & CO., No. 9 Gold street, New York,