V. L. M., of Pa.—Your last invention submitted to us has been longer known (but not in use) than the one suggested to us before. The invention of Dr. Townsend, illustrated on page 241, Vol. 2, Scientific American, describes yeur last proposition ex* aetlj, and the placing of canvas curtains around the edges of the cars and allowing them to drop near the track, is an invention in use on some of our railroads at the present time. So your previous sug gestion is not new. The use of curtains as applied on the New Jersey Railroad are very effectual in preventing the dust from rising, and is the best contrivance we have seen for the purpose—the most effectual for the smallest expense, Don't be discouraged—try again—you hit upon one good idea if it was not new. S. ? , of Pa.—you had better send us a model of your improvement for examination. L. K., of Mass.—The engine and bailer which we have advertised for few weeks back has been sold. E. F. ?1 , of Vt.—If you have got an invention on bank bill paper that will render it impossible to counterfeit or alter bills printed upon it you have a valuable answer. Supposing you send us a fifty dollar bill upon some good specie paying bank that is printed upon your paper, that we may have occu-cular demonstration that what you say of jour in-vention is not overrated. H. H., of Pa,—We have seen no other'account of Fischer's Ram than the one you quote from Ew-feank's Hydraulics, page 371. 'One-third,' pobrably should read 'two-thirds.' No hydraulic ram can raise a larger amount of water than escapee, higher than the source. Three millea above Sohaffhausen at Lauffen is a cataract about 100 feet in height The basin or air chamber, we should think, was at the base of the altar. F. W. ? , of Ohio.—Can you inform us anything new about Cashart's Turn Table? He appears not to have a patent. G- Y., of Md,—Your method of preventing steam boiler explosions is quite well understood j no patent could be secured on it, it is an old contrivance. N. W. P., of Pa.—We do not think there is any chance for you to obtain a patent on the method of securing plastering to brick walls. Our opinion is that it is not the subject of a patent. R. ?. ?., of Ohio —The subject of celestial photography is one worthy of attention. We have not made the microscopical examination which you speak of There are sometimes 4 sun dogs seen, as you will find by consulting any good work on me-meteorological phenomena. Money received on account of Patent Office business for the week ending Saturday, Aug 20:— W. McB., of Ohio, $55 ; L. C, of Miss . $55 ; W D. C. &Son, N. ? , $2b ; F. C, & 8, of N- Y-, $100; G. W. 0., of Q-a., $25 ; T. D.. of Ala., $15; J. W. 8.. of Mich., $30; ? g , of 111., $20 ; N. R. of 111, $35 ;U S. C, of N. Y,$55. Specifications and drawings belonging to parties with the following initials have been forwarded to the Patent Office during the week ending Saturia Aug 20 :— D. B. M, of ?. ? ; D. W. 0. & "Son, ?. ?.; ?. D. ? , of Ohio ; T. D.. of Ala. ; G.B. T., of Ohio ; G. S. C.,of N. Y.
This article was originally published with the title "To Correspondents"