B. B L, Ohio—You must send us on a model if you wish a patent to be taken out; no doubt it would be of sufficient importance, S D. P., of N. Y.—The law of fluids pressing in all directions, would scarcely applv in the case of steam with an ordinary constructed cylinder, because the aides are rigid and fixed, and therefore, however great might re the amount of pressure, it could not be made available in the manner you indicate. Be sides, as the piston does actually yield and therefore pei mits the expansion of the steam, the whole of the power is, in fact, exerted by the engine H L , of Ga—There is no hand press made of such dimensions, the only plan would be to hare one made for the purpose, by which, of course, you would incur additional expense; even then we do not think that a hand-press would be at all adviaa-ble j an adaptation of the cylinder press might, perhaps, answer your purpose. The best work on Lithographic Printing is by Hulmandel, 8ro , price $2,25 : London ; sold by Putnam, New York. H. S W , of Ohio—Your plan is new and patenta-ble, and therefore you are entitled to a patent, but we think it would induce priming, which is a very great evil, J W. F , of Pa.— $20 are the government fees for a caveat. J G-. B., of New York—We have received three articles on the same subject ; we cannot publish them. 0. P S , of Ohio—We have before presented the ideas embraced in your letter. L. D. P., of Ind.—We never publish engravings but once, therefore cannot accede to jour request. S, A. of Vt.—We do not think the agate button is made in this country. L. M. C, of Canada—There is nothing new in a The;mometer which will show what degrees of heat or cold have been during the past 2i hours. The same thing was shown ua some months since. J, G. S, of Mass —We would want a more complete description of treating specimens of natural history. J. F N , of N. Y.—The same thiDg has been presented to us a number of t mes, and is perfectly fallacious; try the experiment, which you can easily do, and you will find out. J. B, C, of Tenn.—The subject is so abstract that perhaps, not three or four others besides ourselves would be interested ia the discussion; we are much obliged to you for your kindness. G. 51., of D. 0 —Your last came in time; you will find the article about oxygea beiog a compound on page 112 Vol.4, Sci. Am., not Vol. 5, as stated. W, A., of Pa.—There is no good work on the subject, nor can you find a process for dye log wool and cloth combined in any book ; for some receipts we would charge $1 but not less than $5 for others. J 0 M., of Albany—The same proposition for beds has been.proposed to us, you will fiud that they will not make good cushions; some element more compressible and yet elastic is better, A. D. S-, of Conn.—We suppose that pine, prepared with an aluminous solution, and Bubmitttd to a heat of 400 degs., would3 after that, stand steam heat of 300 dege. R. G-., of N. If .—The subject is not worth the time you have expended upon it. W. K. P., of Mass.—The oxygen of the air would combine with the red hot iron, and soon destroy your cylinders; it would not result in any advantage to employ hot air along with steam. II. M. H., of N. Y.—It is not ao much the oil as the gluten in ivory which gives it a yellow color you oaaaoE remote it by chemicals without iojuring its quality ; by boiling it ia soda the oil will be removed. C- 61., of New York—The gentleman you inquire aboutlivefs in the interior of this State ; you will find the said volume in the Society Library, we beUeve j if not it cannot be found out of Philadelphia. J. J. L., of N.Y—We cannot publish your letter, it is too long, and its composition and penmanship exhibit carelessness. M- L. P., of Texas—From the very nature of the propelling element which you use, an elastic gas, it is not adapted for propelling a veasel. E.S-, of Me —It should be 1 gallon of water, F. S. C, of Boston—If the water moves at the rate of 16 feet per second, its pressure will be equal to 15 Iba j on the square inch S. H M , of Pa.— Vour criticism upon our remarks on Keelers Smut Machine are evidently captious and disingenuous. We cannot publish the engraving of your machine; it may merit all the encomium i bestowed upon It, but it is too old an invention to be published in our columns. C. &. E , of N. Y.—You will do well to show your improvement bo long as you are in the city. Money received on account of Patent Office business for the week ending Saturday, Feb. 26 : P. C, of Mo., $45; J. A , of Ct, $30: G. D , of N Y , $25 ; G. M , of Ind., $40 ; B. & D , of N Y., $67 ; F B B , of Me.. $10 ; E. J. B., of N Y., $35 ; P F.,of N Y., $50, R F..of N. Y., $30; S T.S, of Maaa., $30 ; W. V. A, of N Y , $35 ; W. D W , of N 0., $25; D. T., of N. Y., $30 ; F. O. D , of Pa., $25. Specifications and drawings belonging to parties with the following initials have been forwarded to the Patent Office during the week ending Saturday Feb. 26: G. & Co., Paris; P C, of Mo.; G. D,, E. M., W. I y A E J., and E. B, of N. Y ; F. 0 D , of Pa ; S. \ T g of Mass ; W D. W-, of N.C. : A B. D., of Pa