P. C. M., of III.—Your remittance of $4 is at hand. We will return your model and patent as Boon as we can spare it. We know nothing about the parties of whom you inquire or their booke. C. B. Thompson, of St. Catharines, C. W., desires to correspond with some party who manufactures the best boot-crimping machine. J. R. L., of Fla__There ia nothing new or patentable in the employment of saws for the purpose of trimming the edge of the board in the operation of tonguelng and grooving. L..H. Thomas, of North Adams, Mass., wishes to procure a machine for crimping zinc Canaome ofour reader* inform him ? B. M. &Co.,of London.—Your letter of the 19th came to hand after yilhv advertisement had expired, therefore too late to make the alteration in it which you propose. D. A. M., of Pa.—You will find an engraving of a grist mill feeder on page S44, Vol. 12, SOL AM., which we recommend you to employ in preference to the old plan. M. L. P., of 111,—You can procure pump augers of tho Amos Manufacturing Company, Chicopee, Mass. G. F. W., of Ohio.—Who are yon ? If you wish attention repeat your inquiries, and let us know who you are, C. S. F., of Me.—You can obtain the book from Scrib-nera\ Park row, this city. The price ia $2 60. C. C, of Me.—You can procure a. ** Koae engine for ornamental turning" from J. Reeee &Son, Hayden-ville, Mass. We do not keep machinery of this kind for Bile. You will find in our advertising columns several reliable machinery manufacturers and dealers. J. M. B-, of Pa.—The difficulty under which you labor at present ia that the Commissioner of Patent's report 13 not yet published, and will not appear in all probability until near the cjose of this year. In No. M of the present volume SOL AM., we published the report in advance of its regular isaue by authority of Congress. You will undoubtedly get it after its issue. Congressional printing joba are very Blow eoachea for this fast age. They are about the only reminders we have of old times. H. J. K., of Maas.—A patent was granted to Thomas J. Spear, of New Orleans, La., July 16,1841, for the following method of making indelible ink. Take three drams of ground India ink, and four ounces of boiling solution of caustic soda, mix these Ingredients together, shake themforabout ten minutes, and the ink is ready for uao. You can try this ink, perhaps it may wit your purpoB9. Any person has the privilege of using It now. H. Z-, of N. Y—You ask, " How many engines can exhaust Into the same condenser and keep the vacuum at twenty inches, with one air pump ?" A dozen stam engines may exhaust into one condenser, and the vaou-um may be maintained with oue air pump, provided the pump and condenser arc large enough. The eapaeity of the condenser and pump must be proportioned to the quantity of steam to ba condensed, not the number of engines. N. S., ofWis.—The cheapest and best floating bridge whieh you can build for winter over a portion of the Mississippi is by loga with their ends put np and down the. stream, well fastened together and planked on the top for the roadway. Connect the ends at each side to strong chains to allow for the rising and falling of the water. J. E. B., of----.It is not a now idea to generate steam in a boiler byinjectin* tho feed water into the boiler or generator in fine spray. If Mr. Paine's proposed invention only embraces this feature, it ia neither new nor useful. C. R. T., of Mich.—Switches have boon arraEged so thatwhile the cars are passing, thoy adjust it, to prevent them from running off the track. The sketch you send does not show how the operation is performed, therefore we can only arrive at a general conclusion, which Is unfavorable to its novelty. M. B, of S. C—Your ideas are good, but we could not carry them into practice without much trouble. IJ. M. M., of N. Y.—A "horse power" means 83,000 pounds, lifted one foot high in one minute. The pressure in a boiler does not indicate the horse power. VIolina are stained dark or light, according to the kind of varnish employed. " Dragon's blood" Is the principal coloring agent for violin varnishes. You ean make them light or dark, according to the quantity used. Z. D.. of Oft.— On page 120, Vol. 5, SOL AM., you will find an artiele on preparing hides for tanning, in which the best methods known to us are described, by a very experienced tanner. A. T. H., of D. C—Onr former answer regarding the impossibility of obtaining an increase of power by simply increasing the diameter of a water wheel, is also applicable to the revolving endless belt bucket motor, which is quite old. J. C, of Ohio.—We have cautioned the public about being too sanguine regarding the sugar crop to be obtained from the Chinese cane, and anything more upon the subject in our columns than has already appeared, would be a waste of space. Your information regarding glucose is interesting and useful. J. D., Jr., of Va.—You will find a fall description of the now alloy resembling gold, on page SOS, Vol. 12, Sox. AM. We do not know why white zinc paint spreads so much when mixed nrlth oil. A good drier should be used with it. M. T., of Iowa.—Weare not acquainted with a single work which describes the process of making Bourbon whiskey, nor is there a book published on the distilla-;ion of American whiskeys. S. ,H. |B., of Ohio__We cannot describe the hot air engine, as it now is, without drawinjfl, BO as to convey a proper idea of its construction and operation. We shall present an engraving of it la a few week*. 6. B. C., of Conn.—Umber, either burned or raw, mixed with white lend, makes the most beautiful buff color for the entslde of homes. You can darken to any shade with ivery black. J. S., of Ohio.—The cartridge of tha Prussian needle gun ia not made of the moat sensitive percussion material "within our knowledge." It Is simply perenssion powder—the chlorate of potash—which yon can obtain hi abundance in the city where you reside, J. R. B., of N. Y., can get the information he wants in regard to old oina by addi'essiag Wm. Travel*, of Camden, 6. C J. S. D., ef N. H.—9tel tools are tempered very hard by quenching them in cold salt brine when at a. red heat. If you wish to render the tools somewhat tough and elastic, temper fcha in oil. There ia no necessity for employing any other Ingredient in the oil. R. S., f Pa__We do not know anything about the ma-chins said to bo patented, whieh uta out fly-net strips of leather, combined with a plnking-Iron. Boa recipes for gold wash in another aolumn. Money received at the Scientific American Office on account of Patent Offiee buelnecs, for the week ending Saturday, March IS, 1858 :— D. &M., of Pa., $30; W. M. B., of Dei, $25 ( W. Y. G., of KyM $25; L. R., of Mass., ?40; D. M. L., of Pa., $80; W. I., of N. Y., $35 ; P. S., of Va., $23; J. W. C, of N. Y., $30; J. H. W., ef N. T., $20; L. W. H., of N. Y., $55; N. A., of Pa., $30; H. B.,of N. Y-, $55; A. M.,fN. Y.,$25; H.M.of N. Y.,$105; J. H.,of Mo., $05; H. B.,of Pa., $25; S. &A., of Mich., $30 ; G. M. L. MoM., of Ohio, $35; TV. W., of N. T., $23 ; W. D., of Wis., $25; W. W. H., of Ohio, $12 : J. B., of Conn., $30; W. D. J., of N. T., $30; T. K. W., of Conn., $30; T. &MeC., of N. Y., $32; C. &B., of N. Y., $20; J. MeC, of Ohio, $10; P. &J., of Ohio, $30 T. F., of N. Y., $30 ; A. D. B., of Mass., $30; B. J, of N. Y., $S0; J. W. G., of Vt., $25; W. M., of 111., $50 ; D. O. Do W., of N. YM $23; M. T., of Conn., $2!; S. W., of N. J., $30; N. F. E., of Vt., $30; W. DM of Mass., $30; T. O-, of Misfl., $10; W. O. P., of N. Y., $80 j J. S. D., of N. Y., $30; H. 8. V., of N. Y., $85. Specifications and dra wlnga belonging to parties with the following initials ha ve been forwarded to the Patent Office during the week ending Saturday, Mareh IS, 1855 :— W. V. Jr., ofN. T.;H. B.,ofPa.;W. M. B., of Del.; P. S., of Va.; J. B., of N. T.; R. B., of N. Y.; B. K, of Pa; W. Y. G., of Ky; H. M., of N. Y., (8 cases); J. HofMo.; D. O. DeW., of N. Y.; O. P. S., of Mcfc W. W. H., of Ohio; J. V. A., of N. Y.; W. D., of Wis.; A. M.,of N. Y.; M. T.,ofConn.; T. &McC.of N. Y.; L. W. H., of N. T. : J. S. D., of N. T.; H. B. V., of N. Y.; O. B., of N. Y. Literary Notices BIACKWOOD s EDINBURGH MAGAZINE.—This able periodical forthe present month (as rpubliahed) contains the "Journalof Capi Burton," authrof the "Pilgrimage to Meeea," and sent from ZanBibar, In East Africa, where he is new travelling. It ia a moat Interesting article. " What will ho do with It T IB eon-tinued, and Is a fascinating story. Published hj Leonard Scott &Co., No, S4 Gold street, this eity. THE ATLANTIC MONTHLY, for Mareh, publish efl by Phillips, Sampson &Co., of Boston, to austaining Its already high character for literary merit, and there ia an amusing sketch in it entitled, "A Welsh Muaieal Festival." 'rim YODSG MEN'S MAG AKINJH for March is fall of the most Interesting and edifying matter. Its well-wishers are doing their utmost to extend its sphere ofusefnlnew, and we hope that thoBe of cur readers to whom it ia ad-dreased will take a look at one number, when we are sure they will be pleased with it* Iubliahed tt MS Broadway, this eity