J. F., oi Ohio—We are much obliged io you lor the information. J. C , of Pa.—We entered the live names for nix months each, and marked jour own subscription up one dollar's worth. Downing Architect, published by 0. I1. Putnam,this city, would answer your jmr-poeo. ? ?. ?, of 111.—It was in Vol. 4, JSci, Am, that the History of llotary Engines was published ; we have not a copy to sell at any price W. L ? , of Conn.—We cannot tell you the greatest number of revolutions that hasbeenor can be obtained by any known power ; nor are we aware that any other person can. J. II. C, of N. H—The Barker is truly a re action wheel; this we knew. Your plan, as exhibited in the sketch, is as good as any other known to us, if you introduce your water in a correct manner You infriDge no patent that we are acquainted with, N.B,,of N. C.—Your question is difficult to answer Measure the quantity of water which falls in a minute, then allow G2 1-2 lbs. for each cubic foot ; multiply by 7, and this divided by 3, o will j;ive the result in horse-power. Givo us the ;LdvaECC from the surface of the inlet water, and we can tell you the horse-power of the water—not otherwise. A. M. G ., of S. C—The water will rise in the funnel and tube to the eame height, if *both are open and actuated by uno pump placed to operate both, but not as in your diagram. Your railroad signal would not answer, the noie of the engine would prevent the engineer hearing the bell. W- ?. ?., of Ind —No doubt your conclusion in regard to the patentability of the invention referred to were correct. The application of Mr. S. was not madethrough our ofllce; the aiticle in question was a communication. D. W. K. B., of La.—We do not know of any hook and eye machines for sale in this citj D. A. K., of Ala.—Saving whecie for caiiiaes are old and well known ; we taw a carriage on the same plan at least 15 year ago. "W. ?., of Mass.—The improvement you describe for propelling is illustrated in Vol. 5, Sci. Am. C. ?. ? , of Ga.—We do not discover anything new or patentable in your apparatus for churning, and we advise HO outlay of money for that purpose. L. Gl ., of ?. ?.—It has been suggested to employ a single tlange in the centre of car wheels on one side only, and a plain wheel on the other side. A model was shown us, but for some cause it has not been adopted ; we nuppose these are good reasons, and if this is tme your plan is liable to the ;imeob-jectitm. J. S,, of Va,—Xt I true, what you bay. "out it is quite common to have the same screen frames as those you speak of in our windows to keep outfli8a5 & c. V. B. V., of Pa.—Your improved brake appears to bo a good one, but not new ; last fall a model was show ? ua at the American Institute Vair, which embraced almost entirely the same contrivance. J. S , of Pa—The improvements in car axles are not uew, the saraothiDg has already been done. The other part of your letter we will consider. G. l 1. JlcM,—We think a machine for the purpose you nama would be very useful ; we know of noth-ID in use which answers a good purpose. F. V., of Va.—3. C. Hill, No. 12 Platt si, this city, will furnish you witli a good boring n,nd mortising machine at a reasonable price. II. L . W.. oi' Pa.—It i.s our opinion that your railroad chair and tie is not patentable. the same thing has beeu shown to tia before. I . P. J t;f Pa-—We CAimot discover a p ? tent able feature in your devico for gathering apples ; essentially the same thing has been used. J.I*, i?., of Ala—We have referred your letter about books to Messrs Harper & Bros. Wo could not give the information de.sired. T.F. K., of Ohio—We have sent your letter to the parties named in the article ; we could not give the information. Money received on account of Patent Office business for the week ending Saturday, June 25 :— G. ?., of Mass., $25 ; ? & D. A. JL, of Pa , $30; J. ? W.,of ?. J, $(50j ?. ?., of ?. Y,,$10; F. ? 13., of Me, $30; J. B., of Ct, *50; 0. C. L , of ?. ?., $25 ; . 8., of N. Y., 7; E.B., of ?. ?., $100; 8. & G-.,of Ct , $25; II L., of Mass., $10; D D, of N.T.. $16 ; J. M., of N. J., $2 ; A O. 11 , of N. Y.3 $32 j J'. E. M., of Ct, $85; AV. W, of ?. ?.; $25 Specifications and drawings belonging to parties with the following initials have been forwarded to the Patent Office during the week ending Saturday Tune 25:— C. B,, of Mass.; J. H. MeG., of Ohio; T. & D . ??., of Pa.; ?.?. B. of Mo ; C. C L., of N. Y. -k G. ofCt.; W. D. E., of MIPS.; W. W , of ?. ?-?. ? ? , of Ct. {2 cases); J. M.t of N. J.: T. It. & / 3o.,of N. Y.