F. D .. of N. Y.-The process of making pll.tent lcn.ther is a complicated one. The varnish consists of one POllIHl of ivory black, ten pounds thick copal varni1:ih. twenty ponnds of linseed drying oil, ::mu t\vcnty pounds of turpentine. Indelible ink may he made by disf:;olying 1 ?\l ounces of nitrate of silver in 5 ?? ounces of strong ammonia and 12 ounces of gum mucilage. It must be kept in the dark. J. H. n. , of 'Vi::;,-Thc best method yon cun pursue is to wash your lovel with weak acetic acid applied with a brnsh ; let it dry on, and repeat until you have the shade you want, then lacquer with any 'varnish you think fit. ",Ve are perfectly cognizant of onI' right to use this column in any way we think fit, and we do so hy throwing it OP:2ll to aU onl' correspondents. J. T. P., of Vt,-To make copal varnish, take hard copal, 300 parts; drying linseed or nut oil, 125 to 250 partg ; and oil of turpentine, 500 parts. :E'irst melt the copul, th1?n add the drying oil, heated ; let them cool a little, and a.dd the turpentine. Great care must be taken that the tnrpentine does not inflame. J. H. j\I., of N. Y.-A suitable engraving to illustrate your invention would co"t $15. D. ll. C. ?? of Ohio.-"Yo will receive your State bank bills at pm' for government fees, as woll as for our own ; lmt WQ would rather have you send ns a draft on New York, The reason for this you ca.n appreciate, as you are aware that we arc obliged to pay the government fee in gold. R. F. B., of Md.-We have no data from which to obtain a calculation of the strength of hollow globes of wrought iron, L. H. :M., of R. I.-James Harrison, Jr., of this city, has a patent for a machine for making spirn.lsprings for furniture use. W. H. B., of Pa,-You will find an article on the subject you refer to, in this week's paper; and yon may ob?? tain further information by consulting Scott's Engiw ncer's Assistant. M. A. K., of Ohio.-You will find your question an?? swered in that to another correspondent-ll. A. L., of Conn., in No. 9 of the present volume. C. G. M., of N. J.-We do not know where you can get a machine for making shoe pegs. They are manufactured in the eastern States, but just where, we are unable to state. II. H., of" MO.-There is no power in the Patent Office to renew a patent after it has once expired ; thereforc, if yon have neglected to ask for the extension until now, there is no chance for you, unless by special act of Congress. Very poor encouragement. C. C., of PU.-Please to send us all the facts in regard to your rejected case. We are inclined to think that by a vigorous prosecution a patent can be obtained. In order to put the case properly into our hands, you will need to revoke the power of attorney given to your fol'mer agent, and confer it upon us. Through onr Branch Office at Washington we fire prosecuting rejected cases with great success. 'V. C. J., of Kenwood.-Smith Reel'S, of Naugatuck, Conn., has a patent for an odometer, which we believe to be a good one. E. G., of -.-Your explanation of the phenomena des"dbed by T. JlIcN., of Ill., about the water in a tin dipper not freezing, while the water contained in the bucket in which it was immersed did, is incorrect, because you assume that the dipper and its contained wa.ter sunk in the bucket; if we understood our corres?? 110ndent's letter, it did not. You will find our expln.nation under his query; and we should like to know your reason for objecting to that explanation. P. S., of Pa.-The best cement for houses is undoubtedly, the so-called Roman cement, which, 'ye believe, can be procured from any dealer in building materials. D. "Y. J., of Ohio.-The mineral which you have fonnd in your locality is heavy spar, or SUlphate of baryta. When made artificially (by precipitating baryta from its solution by sulphuric acid), it is much used for paint. As its name implies, it is very heavy, having a specific gravity of about 4'4. At a very high temperatul'e it fuses into a beautiful white enamel. II. J. F. , of Ind.-Your chain propeller for boats is one of the oldest known inventions for this purpose. It has neither novelty nor utility to recommend it. E. J. N., of Mel.-Just at this time we have no patent law pamphlets on hand. They do not contain the form of power of attorney for the sale of patents. The form in general nse will ans,\yer your purpose. Fn.l'aday's Lectures on Electricity will meet your wants. G. E. D., of Pn.-"'\Ve are very glad to learn that you intend to canvas fOl' subscribers, in competition for the prizes we ofter. There is a good chance to get spending money in this manner, and if you persevere you cannot help but succeed. We shall promptly pay over the cash on the 1st of January next. Bet\l' in mind that we are able to supply all the back numbers from the beginning of this volume. Sample numb8l's sent free by mail. F. S. , of Ya.-\Ve will notice your communication next week. It came a little too late to receive such attention as we wished to bestow upon it. The sugar sample seems to be very good. C. J., of N. Y.-Such a device as yon cIaimis not new. By reference to }\" o. 2, this Vol., SCIE;:'iITIFIO AMEItI(lA??, you will find the claim of an extension gas tube, which fully covers yours. If yon have delayed your application unnecDssarily, it is a misfortune, as you cannot now succeed without u troublesome interference. De?? lays are dangerous. F. :M., of Ind.-The advantage of feeding furnaces with hot air is very great, as you save the amount of fuel necessary to heat the air np to the required heat ; and it also enters into the furnace hot enough to burn immediately. It takes no more fuel, as it may be by the waste gases from the furnace. P. B. J. , of 111.-The vine will grow well in your Stato, and some excellent yftrictics of catawba.havc already been made there. "Ye undcl'8tnntl that the vine culture hns been commenced in the environs of Peoria. and Nauvoo, an!l has been very successful. ]'loney received at tile Scientific American Office on accuunt of l'atcnt Oftlce busin??8s, for the week encling Saturday, November 14, 1857 :II. A. S., ofVt., $25; D. G., of Pa., $39 ; A. D. C., of Ga., $:::0 ; I.J. K., of Ohio, $46 ; A. J. G., of Mass., $25 ; E. II. T , of N. Y.?? $30 ; N. A., of Conn., $GO ; A. M., of N. Y., $30 ; D. Ie. of Ohio, $30 ; ,T. G., Sen., of R I., $25 ; W. ll. M., of Ohio, $55 ; D. W. , of N. Y., $30 ; W. A. F. , of Conn., $30 ; D. II., of Ky., $55 ; II. T. S., of Micll., $35 ; D. B., of R, I., $60 ; N. R. A., cf N. Y., $30 ; D. B., of N. J .. $55 ; I-1. II., of N. Y., $25; F. O. D., of N. Y., $30. Specifications and drawings belonging to parties with the following initials haye been forwarded to the Patent Office during the week ending S??tnrdaYI Novell1?? bel' 14, 1857 :F. O. D., of N. Y. ; A. J. G., of Mass. ; C. R., of N. Y. ; II. A. S., of Vt, ; I-I. H., of N. Y. ; D. B., of N. J. Literary Notices MUSPRATT'S CHEMISTRY-G. B. Russell an(I Bros., 290 Broadway, New York. This work is ing, and although it has already 32, It has only begnn to treat of .. Glass. It -"nll .be volu?? minous in form, and no d?ubt perfect of I.ts k??nd wJ1en ????zP??????C\1 ??f\hee ??1,t??: a??ra!'?fi???y ;:Je ;lA??:?? tb??16id and ??equil'e to be re-written. zinTeI mj nAstT LcoA,mNTmICe nMceOdN TbIyIT t.Yh ei se mthine etnittl ep uobf lais nheinwg mhoaugsaenofu mPhbielrli pcosn, tSaaimnsp asobnly w Cn.ot.t,?? nof a -rBtolcslteosn, ,s Mupaesrsl:O YT, IljlC.l ffiarcstt, ttour teh. e oIrnd rinefaerrye rnucne otof ctohnet rmibeurti.ltOsIl oSf . top amrta;igcuazlalnr ea lrItt.IoCrleasevery reader must judge for himself. reTprIl1En tW??) EpSuTbMliIsNhSeTERd b yR ELY??IoEnWal', df oSrc oOttc to bCe.?r,, N(Aemw eYri??cra??n, lcioznuttaioinns ina Evenrgyl agnodod." aarntIdc lme aonn; tohteh er ??s H, oIsnteo royf. Wofh I.CCh1V I??Spa oesmevle r'"eA uarnodra j uLseti gchr.i"t icism 0 Mrs. Bl'Dlyning's new MT. DHE., CEimnc.EinCTnIaCt i.M EDThIeC ANl.o vJeOmUbReNrA nLu-mRb. erS c. o.nNtaeiwntso ann, excelient paper by Professor G. 'V. L. 1;lJ..ckley .on Hm Fatetmera loen tMheed miceadl icCalo lslceigeensc,"es . and much Interestmg
This article was originally published with the title "Correspondents"