AMERICAN. MECHANICS' MAGAZINE, Museum, Register, Journal and Gazette. "The most valuable gift which the Hand of Science has ever Dr. Birkbeck. VOL. I.-No. 5.] SATURDAY, MARCH 5, 1825. [Price $4 PER ANN. "Lord Bacon seems to limit Philosophy to the knowledge of things useful; recommending, above all, the study of Nature, and showing that no progress can be made therein but by collecting facts, and comparing experiments."-Ferguson. CAMERON'S SODA WATER APPARATUS. are distinctly evident in the figure, When the vessels are filled, the mode of operation is extremely simple. On turning the nut M, the sulphuric acid is allowed to come in contact with the whitening; carbonic acid is necessarily disengaged, and in quantity and rapidity proportional to the quantity of sulphuric acid let down. with lead, working on the pivot below, and through the stuffing-box C. By the opening at D, the vessel is filled up to the dotted line with a mixture of whitening and water; the vessel E, containing two gallon, is formed of lead six-eighths of an inch thick, and is filled with sulphuric acid up to the dotted line; the acid is kept from falling down into A by If the vessels were sufficiently cathe lead plug F, which is conically pacious, 10,000 gallons of carbonic pointed, and fits into a correspond- acid would be instantaneously proing conical opening in the lead pipe duced; but by the alternate turning G; the plug moves straight up and of the nut M, the sulphuric acid is down through the stuffing-box H, allowed to fall down in small porand is prevented from turning round tions, which regulates the disengageby the pin K, which moves in a slit ment of the gas, and prevents too in the bridle L, the screw M being great an effervescence, as the gas is riveted loose into the top of the bri- still accumulating. Having no way dle; by this means the conical point to escape it passes over into the vesof the plug is preserved from injury, sel V, and is there absorbed by the as it is merely lifted out of the open- water. In this way, a pressure of ing, and again pushed into it. This from 20 to 30 atmospheres may be is more complicated than a common- thrown into the vessels, It must, formed glass or lead stop-cock, but therefore, be obvious to every man neither of them will answer where a of science, that if the vessel A were high pressure is applied. The pipe connected by a pipe with the valves N, inserted into the top of the vessel of an engine somewhat similar to a E, and into the pipe S (which encloses steam engine, the vast pressure the plug,) preserves the equilibrium which can be so instantaneously proof pressure; so that the sulphuric duced, would raise and depress alacid rises no higher in the pipe S than ternately the piston of a cylinder; in E, and consequently preserves the brass work of the stuffing-box. The intermediate vessel o, containing three gallons, is formed of thick lead, or cast iron lined with lead, and filled with water up to the dotted line. It is employed for retaining any of the sulphuric acid, in case it should be carried over by too strong an effervescence. The vessel V, containing sixteen gallons, may be formed either of copper tinned, with an agitator of the same metal, or of cast iron lined with lead, of from six to eight pounds per square foot, and an agitator of maplewood, which gives no taste to the water. It is filled to the dotted line with water, and a proportional quantity of carbonate of soda, magnesia, or other substance, to be impregnated. T is a pressure-guage, containing mercury; in the Fig. it is placed on the top of the vessel, but it is more convenient to place it at a little distance, forming a communi- This circumstance affords ground cation by a pipe. The communicating to hope that an engine, constructed pipes are lead, and their several uses on the principles of the Rev. Mr. that cylinder, too, would only require to be 1-20th the diameter of the steam cylinder to have an equivalent power, and the gas would be reduced to one atmosphere by its alternate escape at the opposite valves, no water being required for condensation ; but, unfortunately, the expense of sulphuric acid, from the quantity required, (when the gas is allowed to escape,) presents an insurmountable obstacle as a substitute for the steam engine. Since Mr. Cameron discovered the power obtained by the production of carbonic acid, and put it into practice four years ago a fact which was noticed in most of the journals and newspapers of the day-Sir H. Davy has turned his attention to the subject, and discovered that gases, at a high pressure, are powerfully acted upon by slight increments of temperature, and that the pressure is astonishingly augmented. IMPREGNATION OF OILS FOUL APARTMENTS ON TURNING. Sterling's air engine, may yet be made to equal, and, in many cases, to supersede the steam engine. The foregoing is the substance of a letter written to Dr. Brewster by the inventor, and published in the Edinburgh Philosophical Journal. I am, Sir, &c JAMES MARSH. Woolwich, Aug. 14. of anointing the tabernacle, &c. The Encyclopedists profess to think, that the substance here designated by the term "kinnamon," must have been a gum, or an oil, rather than an odoriferous bark. Immediately after the enumeration of the aromatic substances, Moses is directed therewith to prepare an oil of holy ointment," an ointment compound, after "the art of the apothecary, a holy anointing oil." The process for preparing the oil, or ointment, is not farther stated. There is much probability that the holy oil was prepared in a manner approximating to the process above detailed. 66 The following are the articles directed to be used by Moses in compounding the IMPREGNATING FIXED OILS WITH ES- holy oil, or ointment: SENTIAL AROMATIC OILS. SIR,-The subjoined passage, respecting the art of impregnating fixed Oil with the essential Oils contained in aromatic Seeds and Barks, I have extracted from a small work on the Medical Topography of the Interior of Ceylon, by Mr Marshall. Pray give it a place in your widelycirculated publication; some of the chemical readers of which will, perhaps, be kind enough to state, through the same channel whether they consider Mr. Marshall's conjecture regarding the mode of compounding an oil of holy ointment,' as directed by Moses, Exodus xxx. 22, 24, possesses a feasible foundation. دو F. P. C. "Water alone is wanted to complete the requisite substances needful for the above process. for preparing perfumed oils have been simi- FOUL APARTMENTS. Hold your head as high as you can, when obliged to go into a place where the air is foul; foul air always sinking to the bottom of an apartment. Do not sit or lie down as you value your life. "The Kandyans, as well as the natives of the Peninsula, of India, are acquainted with the art of preparing compound and odoriferous oils, by impregnating fixed oils with the essential oil which is contained in aromatic seeds and barks. Oils of this kind are occasionally externally applied by the Kandyan Vederales. The process is as follows:-After the aromatic substances are coarsely powdered, they are put into an earthen vessel; the fixed oil is then added, and afterwards water, sufficient to cover the dry substances introduced; the vessel is put upon a fire, and the water made to boil; the boiling is continued until great part of the water is exhaled. During this process, the essential oil of the aromatics unites with the fixed oil, and impregnates it with the peculiar fragrance of the odoriferous seeds or barks used. Perhaps a knowledge of this fact may contribute to obviate the diffi- SIR, Will you permit me, through culty brought forward by the compilers of the medium of your excellent work, the French Encyclopedia, in regard to the to thank G. A. S. for having given me cinnamon mentioned in Scripture. They aver, that the kinnamon of the Hebrews, the first intimation of there being mentioned in Exodus, chap. xxx. is not that such a work on Eccentric Turning as of the Greeks and Romans, the modern cin- Mr. Ibbetson's. I have just procured namon. Moses was ordered (see verses 22, the volume from London, and think 23, and 24) to take cinnamon, and other aromatic substances, of which he was to make it a valuable book of instructions for an oil of holy ointment," for the purpose beginners in eccentric turning. I BOOKS ON TURNING. hope we shall soon receive the in- certain the proportion of extension formation which your Correspondent to the weight applied, I had two G. A. S. has offered you, with the marks made on the strap, at six drawings of the chucks and tools inches distance. which are used in the art of turning. There is another book which, perhaps, is not generally known, and which was published about a year after Mr. Ibbetson's, by Mr. Ritch, entitled "Specimens of the Art of Ornamental Turning, in Eccentric and Concentric Patterns;" sold by Skelton and Co. Southampton, and Whittaker, London. It contains six large plates, engraved by Lowry, of vases, temples, and pagodas, inaking handsome ornaments for chimneypieces. The fracture was not at the centre of the strap, where the contraction was the greatest, but at one end, occasioned by a slight cut of the vice by which the strap was held. INQUIRY. I shall be exceedingly obliged to any of your Correspondents, if they will inform me of the best method of staining or dying ivory. The ratio of extension by half red and black, such as chess-men, the breaking weight, expressing the billiard-balls, &c. I have tried the length by unit, was 0.22, or nearly receipts given in books, but the co- one inch for every 4 inches in lours produced by them are not so length; the force of cohesion per beautiful as those produced by the square inch being 3981 lbs. and the manufacturers of brilliant balls. modulus of cohesion equal to 10049 feet. 1 am, Sir, &c. AN AMATEUR MECHANIC. Falmouth. In a similar manner I tried other species of leather, and obtained the following results: ON THE STRENGTH OF LEATHER. SIR,-In most of our elementary treatises on mechanics will be found tables of the strength of various substances, such as the different metals and various species of wood, and also of ropes and cords: but I am not aware of any good experiments on the Strength of Leather published in any of our books of general circulation; and as leather is an article of very extensive use, both in harness and in machinery, I consider it an object of some importance to be a little acquainted with its strength; for the benefit or amusement of your readers, I beg leave to send the result of some experiments on that subject. I took a piece of good leather, manufactured from a cow's hide, such as is usually made into harness; length 13.30 inches, width 1.32, thickness 0.14, and weighing 1.2 ounces avoirdupois. In order to as CENTRE OF GYRATION-REFLECTING LIGHT-HOUSES. To find the weight necessary to break or tear asunder any strap of leather, it is only necessary to ascertain the weight of one foot in length in lbs. and decimals, and multiply the modulus in feet by the weight so found; the product will be the greatest load the strap will bear, even when the leather is new, but not more than or of the weight thus found should be trusted for any considerable time. B. BEVAN. CENTRE OF GYRATION. SIR, Dr. Olinthus Gregory, in his excellent Treatise on Practical Mechanics, art. 312, has inadvertently given an incorrect theorem for finding the centre of gyration of a cylindrical ring, and unfortunately, this error has been copied into Morrat's very useful Introduction to Mechanics, page 381; and as the most essential part of a fly-wheel consists of such a ring, some of your practical readers may be a little puzzled by this error in books of such general utility. This notice, I trust, will be accepted, as it is intended to prevent practical errors, and not to depreciate the value of the above-mentioned publications. Let R denote the distance from the centre of the fly-wheel to the outside of the rim, and r the distance from the centre to the inside of the same, then R4—4 distance of the 2 R2 2r2 centre of gyration of the rim. B. BEVAN. REFLECTING LIGHT-HOUSES. The use of mirrors for reflecting light-houses in England is of very recent date; and although the idea was not suggested by the falling of an apple, nor the dissection of a frog, it owes its origin to a circumstance almost as trivial, which was as follows: At a meeting of a Society of Mathematicians at Liverpool, one of the members proposed to lay a wager that he would read a paragraph of a newspaper at ten yards distance with the light of a farthing candle. The wager was laid, and the pro 69 poser covered the inside of a wooden dish with pieces of looking-glass, fastened in with glazier's putty, placed this reflector behind his candle, and won the wager. One of the company viewed this experiment with a philosophic eye. This was Captain Hutchison, the dock-master. With him originated those reflecting light-houses at Liverpool, which were in the year 1763. In his Treatise on Practical Seamanship, he says, "We have made and had in use here at Liverpool, reflectors of 1, 2, and 3 feet focus, and 3, 51, 71, 12 feet diameter, the three small ones made of tin soldered together, and the largest of wood covered with looking-glass; the two large ones, called the sea-lights, leading through the channel from the sea, till the two Hoydule lights are brought in a line that leads into a very good roadstead to lie, till it is a proper time to proceed to Liverpool." Glasgow Mechanics' Magazine. [Antecedent to the year 1812, Capt. Winslow Lewis of Boston, obtained a patent for an improvement in reflectors for Light Houses. The Government purchased the right, and since that period, they have been United States. generally introduced into use in the consists in conforming the reflectors The improvement to the parabolic curve, and furnishing them with glass chimnies. They have proved far more beneficial to mariners, than the lights formerly used, while the expense for lighting has been considerably diminished; but there is room still left for the exercise of economy, both in respect to the manner of lighting, and in the structure of our Light Houses. The former ought unquestionably to be effected with gas, because the lights would be more clear, and the expense would be very trifing, particularly, if tar were to be used for its manufacture; while cast-iron supporters for the lantern it is believed, might be elevated to a considerably greater height, than our Light Houses are at present, and at a less expense; besides there would be less difficulty in securing foundations, so that they might be used on the morasses of the Mississippi or elsewhere.-Ed.] |