S.B.B., of VtThe mere application of any well mown substance to a new purpose is not patenta-le, and jour invention is simply one of adaptation. E. W. S., of Mass The Patent Office Reports for o many years back could not be obtained for any trice. S, G-. C., of Pa.We do not see the least advan-age that you can obtain by using the carbonic acid gas from the fire, mixed with the steam, to operate our engine. J. H. F., of Vt.Wo should be pleased to have ou form a club of subscribers for the Scientific Lmerican, but we cannot offer you other induce-nents than those laid down in the prospectus. P. , of Mass.Yours has been received and will meet with attention. W. P., of Pa.Your deductions appear plausable, ut they will not account for all the phenomena we bserve ; how does it account for the various colored rains? haveyou tried the effect of preventing the pollen from falling upon the staminate at all. Ex- erimentsalone will determine the true theory. L P., of Pa.Your argument is ingenious, but it s founded upon an erroneous view of the effects of leated air ; we it'.'er you to the views embraced in ruth is mighty, and our views will be found to be orrect ; we are nowise uneasy about the fwture, it will, and is, developing the sound doctrines promulgated in the Scientific American respectinf Pulley, Static Pressure and Caloric Engines, Water Gas.Fire Lnnihilators, etc.; we mean to protect our own eaders: for them we devote our energies; we are atif.fied with our past labors. You find fault with our plainness j we care not for this, we expect it. S L. B., of MichYou are correct, compressed air passing into water will absorb a portion of ca-oric from the water and render it cool; for an ap-)lication of this principle see the air-cooling apparatus in No. 38, this Vol. Sci Am. S. L. II., of 111.--Yours is not " a worthless fancy,''as you state, but very ingenious; you must, aowever, see " House's Telegraph," when you will be convinced that he has produced a machine carrying out the same idea A. C. S , of N. YDifferent gases have different specilic gravities: air is 0 0038, carbonic acid 1383 ; air is 815 times lighter than water ; a cubic foot of carbonic acid gas is therefore 532 times lighter than a cubic foot of water, which weighs 62 5 lbs. J. B. C., of OhioWe do net see any chance for you to get a patent on the head rest for cars. The same thing, substantially, has been long known and used. You had better not apply. A. II., of PaWe have examined the sketch of your improved compound car axle, it contains no new or patentable feature, and you are advised to drop it ; several pertinent references could be given. D. P. /,., of Ct.You do not appear to be aware of the fact that dry meters are well known, also the use of bellows as an attachment thereto ; yours is differently arranged from any other known to us, but thewatermeter is superior to any other. If yours is useful it is patentaDle, we think. Money received on account of Patent Office business for the week ending Saturday, June 11 : J E. A., of N. Y..S30; E. P., of 111 , $10 ; S. D. Co of Mass . $25 ; W. W-, of N. Y.. $30 ; W. S . of Pa, $35; W. G. M.. of N. Y., $25 j S K, of Mass., $30; J. H., of N II., $15; V. S. (assignees), Belgium, $342; 3. P., of Ky , $60 ; A. A , of N. Y., $55; W. A. II., of Canada, $500 ; J. S . of Va., $20; J. S B of Pa. fSO; T. II. T., of N Y., $10; 3. McG., of O $20; a. k B.,of N. Y., $30; A. V.O., of L.I., $22; C M.,of N. Y., $.50. Specifications and drawings belonging to parties with the following initials have beeu forwarded to the Patent Office during the week, ending Saturday June 11: W. C , of Ga ; R. S. T . of N C ; J H., of N II ' S K., of Mass. ; W. G. M., of N. Y j A R.. of L. I J B. A., of N.Y.; J. II., Jr., of Wis. ; J. T.D . of N. Y.; W, (!. M., of N.Y.