R. B., of Pa.—Fuse thirty vurts of ginn cural in an iron vessel, and then pour in a like qunntity of boiling linseed oil, rendered "drying" with sulphate of zinc, stir all well until the gum is dissolved, then cool down to 150 Fah., and a,dd fifty parts of turpentine, now stir all thoroughly again, cover up the vessel close, and allew the contents to cool slowly. This makes a good varnish for handles of tools exposed to the weather. w. B. R., of R. I,—We have always recommended the use of soft water when it can be obtained for steam boilera. If you turn back and read the articles published in former volumes of the Sm. AM, on water for steam boilers, you will find that we have uniformly advised the purifying of hard water before it enters the boiler. The prevention of incrustations by the use of chemical compounds, oak blocks, and sawdust, is the adoption of a lesser to remedy a greater evil. S. S., of Ind.—The first electric telegraph laid down in England was inclosed in glass tubes, and buried alongside of the Great Western Railway track. Your method is to enclose the wire in a hollow part of the rail; the same plan has been presented several"times to our notice. It is not so good as the method at pre-seutinusc. The wire would be too near the metal of the rail; insulation, therefore, would be very imperfect, and besIdes it would bs very difficult to make repairs. J. J. 0., of Ohio.—The Price Caudle Company, of London, usc a consideraLle amount of paraffine in the manufacture of their celebrated candles, and could probably give you all needful information as to its market value in England. We slmll be glad to get those statistics whenever you arc prepared to furnish them. J. McM., of Ohio.—In the official list of Patent Claims, last week, is one for an apparatus for lighting gas by electricity. If you will send a sketch and description of yours. we can determine as to its novelty, as we are familiar with this subject. F. R. E., of Pa.—Thcrc U a brief dcscliption of a gunpowder engine in " Stewart's Anecdotes of the Steam Engine," but gnnpowder is inapplicable as a motive agent, owing to its sudden expansion into gas when ignited. The dirt formed by it after combustion is not the only insuperable objection to its use in cylinders, but also its actioD—operating in a succession of shocks, instead af by equal expansive pressure like steam. D. R, of Mass.—If you had taken out a patent in due season for the curvilinear saw-mill, you would have been a rich man to-day. By procrastination you suffercd another (who has now become wealthy) to invent, and subsequently take out a patent for the same thing. You should not neglect your other improvement until one has forestalled you in like manner. This is not the time for inventors to postpone for a single day making applications for patents on their inventions when completed. A. P. M., of Ohio.—The quickest and best method of dissolving gutta percha is by immersing fine shavings, or cuttings of it, in naphtha, which must be kept in a warm place in a close Yessel, and frequently stirred, until the gutta percha is dissolved. If you cannot obtain naphtha. use rectified spirits of turl)entiue, which is nearly as good. D. A. B., of Ala.—The idea you :mggest of transmitting the mail throngh an air-tight tube is not new. Tho use of a steam engine' to blow the piston through, to which the bag is attached, is not different in principle from the atmospheric plan of Mr. nichardson, illustrated on pnge 265, Vol. 8, SCT. AM., and in theory or practice it is not so good as the device referred to. A. S., of N. Y.f- T"ere is nothing so good as a model or machine to get up engravings from. A good photo. graph will answer if the machine is simple j but drawings of a complicated piece of mechanism should always be made from a model or machine. In your cnse, if the photograph is wo:l taken. it may answer our purpose ; but we much prefer a model or machine to take the views from, and may require the latter after seeing your photograph. H. H., of Ill.—You had better Ollen correspondence with the Childrens' Aid Society. in this City, in regard to the wants of your scction. This society is doing a noble work in providing homes at the West, ncting as a sort of exchange agency between the destitute here and those who feel it in their hearts to respond from the country. C. S., of Mass.—Your theory respecting the cause of vibrations in some dams, we think, ia correct. The inquiry to which you have reference extended to the use of pipes for very exposed situations j ot course we could not recommend gutta percha pipes if there were the least cause to excite a doubt in their usc. For many situations we belive they are superior to lead pipesj but if rats have, in some instance!, gnawed into lead water pipes, they, no doubt, can cut through those of gutta perclla with greater eaae; at least. it appears so to us. J. A. H., of Ill.—A patent could not be procured for arranging boxes upon an endless chain, for the purpose of carrying off and dumping dirt, &c. This device is now used for analogous purposes, such as elevating mnd from the bottom or rivers, raising dirt from excavations, also for feeding brick to the press, and other similar uses. S. C. M., of Ind.—If you wish to advertise your invention through our columns, you can do so by paying the usual rates, M published in another column. D. B. Po, of Pa.—The employment of water-tight sacks, made of india rubber or other elastic material, for the purpose of raising sunken yessels, is old and well-known. You cannot expect to get a patent on such sacks. , E. B., of Mass.—With a six foot fall and six inches opening, you will not have half a horse-power to drive a wheel. A hydraulic ram will suit your purpose better J than a wheel. Yon will only be able to elevate about one-eighth the quantity of water fifty feet by a six-foot fall. E. F., of Cal.—No government or society has ever offered a premium for the "quadrature of the circle." It is a popular error, which has been accepted by many parsons, and is entirely without foundation. We cannot advise you how to bring your discovery (if discovery it be) before the mathematical world, and honestly tell you that we do not believe in the solution of such a problem. Shepler & Clark, of Chambersburg, Pa., wish to cor- ! respond with manufacturers of wood-working machin- I ery, new and second-hand. j R. B. W., of Wis.—Your communication contains nothing of interest to our readers, as nearly every millwright adopts your method. We are, however, obliged to you, and shall be happy to hear from you again. E. H. M., of Pa.—We have never been able to find Patent Reports back to 1844. Our opinion is that you cannot procure the Reports for a successive series of years. We occasionally meet with stray copies at second-hand bookstores. W. 11 B., of Tenn.—In Campbell Morfit's work, published by Parry & McMillan, Philadelphia, you will find the information you want in reference to various kinds of soaps. Lavender will grow in this country as well as in Europe. Address Professor Silliman, New Haven, Conn., regarding his Journal. H. B., of Ind.—We cannot give the information you want. Address Lowell Machine Shop, Lowell, Mass. A. H., of Wis.—It is evident that you are an inventor of the true metal. There is no use in being discouraged by the adverse state of the times. Now is the time to prepare for the future. The people of this country are not to bs killed off in this manner ; already there are signs of improvement ia various quarters. All will eoon come round again to a healthy condition. R. C., of London.—We were obliged to modify your advertisement before its publication could be admitted. Such advertisements in this country are liable to involve publishers in trouble. W. Fishbach, of Stanardsville, Pa., wishes to correspond with manufacturers of bent rims for truck wagons. J. B., of N. Y.—Bslt saws are old, and have not succeeded. J. G., of N. Y.—It is not possible to get a patent for the use of hollow cane pipes for wells, cisterns, &c. No doubt cane is lesa liable to the destructive action of the elements, but to substitute its use for metal could not be considered as the subject of a patent. A. W. S., of Conn.—Electro-magnetism has already been tried for car brakes, and is not patentable in this application; nor can it ever be rendered efficient, because it would require such immense batteries to be carried by the train to operate the magnets. R. F. B., of Mo.—A gloss caa be put upon white or colored cotton, linen or woolen goods by severe pressure. The gloss on linen pieces is produced by the calendering process, that on shirts by hand-ironing. The collars and bosoms of the shirts are thoroughly starched, then ironed on smooth boards covered with white pasteboard, to form a firm smooth surface. The irons must be pretty hot, pi'eised hard on the linen, and rubbed back and forth very rapidly. F. W. M., of Vt, asks the following questions :—Alter a claim forti patent has bsen rejected by the Commissioner of Patents, is there any otherappeal ? Can Congress issue a patent ? If so, will any further attempts be made to get — 's case patented? Answer :—The Commissioner's decision, or the Appeal Board which assist him in the reviewing the decisions of the Examiners below, is the last step in the Patent Office, but the case may be taken to the District Court on appeal, by paying an additional fee of $25. This decision wouli be final. Congress will not interfere with the Patent Office department to grant patents, but may be petitioned to extend them after a petitionf or an extension has been refused by the Patent Office. The case referred to will be appealed to the District Court. J. H. C, ot'N. Y.—Address any of the manufacturers of turbine wheels who advertise in oar columns ; tell them what you want, and the amount of your water power, and you will, no doubt, be able to obtain such a wheel as you desire. We do not know the price of burr blocks. You are quite right regarding the "fishing" of T-rails. Their joints, as you describe, should be so formed as to present a smooth face to the wheels. The track would be more durable if laid in this manner. M. G. F., of Mass.—It would occupy too much space in our columns to give you rules for the construction of reflectorsforlanterns. Get Dick's or Brewster'swork on the construction of philosophical instruments ; you will find full instructions in either of them. C E., of N. Y.—The general rule in shading drawings is to allow the light to come from the left corner. This, however, is not a rule universally followed by draughtsmen. A method of applying and operating a corn-planter by the foot, different from the one you describe, would be patentabls. Principles are not patentable, only the means embraced in applying them. L. A. H., of 111., inquires, " When a patent is issued to two or more persons jointly, can either of them sell rights and make valid deeds for l the same, without the knowledge or consent of the other parties holding an interest in said patent, or in selling a right, is it ne-necessary that each individual to whom the patent is issued should sign the deed or contract Tl Ans.—Under such circumstances both parties whose names appear in the patent must execute the assignment in order to make them legal. H. J. B., of N. C—There is no secret in the art of putting up oysters in self-sealingcans, nor is the process patentable. Y. Z., of Pa.—A('perpetual motion" means a machine which has the power to set and maintain itself in motion. It should also have a compensating arrangement to prevent or supply the wearing out of its parts. G. B., of Mass.—Sound is a peculiar sensation of the mind produced by the vibrations of the atmosphere acting upon the ear. The deaf are unacquainted with sound, therefore without the sense of hearing, sound S would be unknown. ( F. G. R., of Va.—The best way of rendering lard is by heat and straining in clear vessels, at as low a tem- perature as it is possible to use. Common sal-soda, which you have employed for this purpose is not suitable ; it has a bitter taste, and forms the lard into an imperfect aoap. Money received at the Scientific American Office on account of Patent Office business, for the week ending Saturday, January 2, 1858 :— E. C. , of Mass., $25 ; II. II. I,., of 111., 25 ; A. B., of Ohio, $30; T. G.,*ofPa,, $30; W. C. D., of N. Y., $100; II. & G, of Ohio, $30 ; S. W., of Moss., $130; E. W. S., of Ky., $305 ; S. B. & S., of Pa., $30; W. G-., Jr., of N. Y.. $37; I. C, of N. II., $40; C. & B.. of Conn., $25; J. H. G., ofKy.,$30; M. W., of L. I., $30; J. & S. P. P., of N. J., $25; G. P. K. Jr.. of Ind., $25; E. B. B., of La., $29 ; W. iL, of N. Y., $250; C. A. C, of Pa., $135; S. E. T., of Conn., $35 ; L. W., of Ohio, $30; L. S. C., of N. Y., $27; J. C, of N. Y., $27. Specifications and drawings belonging to parties with the following initials have been forwarded to the Patent Office during the week ending Saturday, January 2,1858 :— E. C, of Mass.; H. H. L., of 111.; J. C, of N. Y. ; M. &G.,ofN.Y.; C. &B..of Conn. ; J. & S. P. P., of N. J. ; G. P. K, Jr., of Ind. ; E. B. B., of La.; E. G. E., of R. I,; L. S. C, of N. Y.
This article was originally published with the title "Correspondents"