268 STEAM DRYING WOOLLENS. our 9th volume, p. 25. The remain- which we leave our engraver to deing three are fanciful varieties, scribe. SOCIETY FOR PREVENTING LOSS OF LIFE BY FIRE. defective, for want of some good contrivance or means for carrying 'off the steam as it arises from the wool or cloth; consequently the air in the stove becomes saturated with moisture, and it then condenses upon the walls or materials in the stove; the evaporation is checked, and goes on very slowly. It is obvious that the steam cannot rapidly escape, unless there is a corresponding and sufficient supply of atmospheric air let in; this is sometimes done by the door being left partially open, but generally the air forces its way in through the crevices and defects of the building. The object of my present communication is to suggest a simple and unexpensive method of obtaining a supply of warm and dry air, so that a gentle current may take place in the stove, the steam thereby be uniformly carried off, and the evaporation greatly expedited at ary tempera ture. When the steam boiler for warming the stove is being set, I would recommend one or more cast iron pipes to be fixed in any part of the side flues most convenient, but sufficiently far from the fire to prevent the possibility of their melting or burning through. The lower ends of the pipes are to be carried to the outside of the wall, that they may be supplied with atmospheric air; the upper ends are to be introduced through the floor of the stove. By this means, I consider a constant and uniform supply of warm and dry air will be conducted into the stove, which may be regulated either by a valve or other means. A little experience will soon point out the proper quantity for carrying off the steam and keeping up a gentle current. I have but little doubt that a stove, warmed entirely upon this principle, would answer [very well, and be more economical than any other method I have seen. I am, Sir, Yours, &c. 269 and everything relating thereto, I often cast my eyes over the former volumes of your valuable and interesting work. While thus employed a few days since, my attention was attracted to an answer in vol. iv. by a student of six months' date,12 to an inquiry why the composite should be placed above the Corinthian order? For my own part, I should think that no one, really styling himself an architect, would be guilty of using the two in the same building; as the former is a Roman, and the latter a Grecian order. But, in the second place, if used together, it would not signify which was made the superior; for having once violated all rules by introducing both, there would be no more harm in doing so a second time, by making either the one or the other the superior. I should, however, as a matter of taste, give the preference to the Corinthian; for how can the volute in the former be considered as light and tasteful as the caulicula in the latter? With regard to the propor tions, I conceive them to be alike, and have always given twenty modules to each column, and five to the entablature. I remain, Sir, Regent's Park. LAMBDA. SOCIETY FOR PREVENTING LOSS Sir, In reply to the inquiry of "Humanitas," in your last Number, "What the Society for Preventing Loss of Life by Fire is about, that it has not been of the least use in cases of fire since its establishment ?"—I beg leave to state, that the Society has been actively engaged in pursuing measures for accomplishing its proposed objects. It has sought for, and obtained, the sanction of many eminent characters of talent and influence. It has been instrumental in bringing together a variety of ingenious inventions for rendering assistance at fires, and, consequently, acquiring some judgment for the choice of such as are likely to be most useful. Thus much for what it has done. The next object contemplated, is a Sir,-As an admirer of mechanics, public meeting; and it is hoped that Bowbridge, May 12th, 1829. H. H. COMPOSITE AND CORINTHIAN ORDERS. 270 INQUIRIES ANSWERED. the numerous cases which have occurred of the destruction of human life by fire, are sufficient to convince the public, that an Institution, having for its object the prevention of such awful calamities, is deserving of its support, and without which the Society cannot be extensively useful. Allow me to add, that the scale of subscription is so moderate, that it is in the power of every one to contribute; and every individual should consider, that he is liable to be placed in that situation which may require the assistance proposed. I am, Sir, Yours, &e. JOHN HUDSON. 86, Cheapside, June 3, 1829. INQUIRIES ANSWERED. Zero's Railway Question.-Sir,-It is well known that the velocity acquired by a body descending down an inclined plane, is equal to that acquired by a body falling freely through the height of the plane. Your correspondent here does not seem to be aware that the waggon will move with an accelerated velocity. As your correspondent has not stated the length or height of the inclined plane, I will suppose them all of the same height, viz. 18 feet, or 193 inches. The following Table will shew the length of the different planes, the height being supposed 16 17 22 feet; and also the weight, hanging over a pulley, which will set the waggon in motion; and, the same power continued, the waggon will reach the top of the plane with the same velocity as that acquired in descending the plane. A. D. W's Questions to Miners. Sir, Your correspondent "A. D. W.” (vol xi. page 12) wishes to know the most effective mode of conveying ore, situated 350 yards from the shipping place, down the side of a hill, angle 31o. There is no doubt that by an inclined plane will be the best mode; but as there are several ways of erecting the machinery, I would recommend the following, because the plane will be a long one: Let a horizontal wheel, eight feet diameter, be placed in a frame close under the road, at the top of the plane, to work with an endless chain, running in a groove round the back of the wheel; the chain, as it is delivered off the wheel on one side, at 12 feet distance, to work over a perpendicular pulley; and opposite let there be another pulley, at the same distance from the wheel, carrying the chain, upon the wheel on the other side; the two pulleys to stand upon the angle of the plane, with the groove that the chain runs through upon them, exactly level with the groove in the horizontal wheel. The chain at the bottom to go over two perpendicular pulleys, and round three horizontal ones; the whole of these pulleys at the bottom of the plane to be placed in a frame also under the road; the chain will run under the carriages upon the plane; the whole of the pulleys, top and bottom, 18 inches 271 diameter each. The machine to be regulated by a break round the horizontal wheel, According to this plan, the pressure upon the break will not be so great as working two single chains upon a drum-barrel, by reason that the weight upon the chain will be proportioned. Suppose there are working on the plane three carriages on a side,—that is, three loaded ones going down, and three empty ones coming up the other side; one loaded carriage will be at the top, one on the middle, and the other at the bottom (observe, the carriages may be placed upon any part of the chain); the empty ones returning up with the other side of the chain, in the same proportion, which keeps the pressure upon the break regular and light. If the plane be worked by a drum barrel and two single chains, the weight must necessarily be at the ends of each chain. There often would be a good deal of difficulty in starting from the top, by reason of the length and weight of the chain returning with the empty carriages attached to it on the other side; but when the descending weight is near the bottom, and the empty carriages near the top, the pressure upon the break must be immense; therefore the advantage of working the endless chain is obvious-ease, regularity of motion, dispatch, and less wear and tear, because less friction upon the chain, and upon the break. Such a piece of machinery, upon a plane 350 yards long, angle 31o, with three carriages on a side, carrying one ton each, or with two on a side, carrying one ton and a half each, would send down 150 tons per day. The chain, half bolt best iron, carefully shut on the side (not on the ends, as is the common method), and with the links so short, that the end of the piece of iron that the links are made from, will barely go in a link in the chain, between the ends of the two next links; such a chain would do the work of 150 tons per diem for 6 years. Your correspondent wishes to know how long a chain would last, to send down about 10 tons a-day, or 3000 tons per annum. He may calculate from the above data, taking into his calculation what the chain may lose by rust, in lying idle 23 hours out of the 24. A rope would be more likely to get damaged by lying idle than a chain. There is no doubt but a road made of fir timber, may do to send down ten tons per day upon. The carriage-wheels should not be less than three inches in breadth, to work upon wood. If the timber were laid upon light iron plates, either wrought or cast iron, the two substances would together make an excellent road. If the trucks he mentions are to slide on the plane without wheels, such things, I think, are unquestionably bad. Such a chain as I have described, made with half-inch iron, is equal to draw five tons at a time on wood, with three-inch wheels under the carriages, up an angle 15o, to the crushing mill. Observe, that the carriage will be attached to the endless chains, by chains about four feet long each, with a hook at each end for that purpose. There is a method of working a plane upon the same principle as the above, with the chain over or on the top of the carriages, instead of under; but the one I have described is the easiest to erect, and equally good.I am, yours, &c. Thomas Deukin,Blaenavon, 7th April. Mr. Hopwood's Chemical Inquiries, vol. xi. p. 82.-Sir,-In answer to the "Chemical Inquiries" of Mr. Hopwood, I beg to submit the following: Table of the Quantities of Real Acid taken up by Alkalies and Earths, according to Dr. Wollaston's Table of Chemical Equivalents.-(From "Parkes' Chemical Catechism," 11th Edition.) The phenomenon mentioned in his second inquiry may, I think, be accounted for by the platinum being a very bad conductor; and will happen, when either sulphuretted, phosphorated, or carburetted hydrogen are used. On this property Sir Humphrey Davy founded the improvement of his safety lamp, by suspending a coil of platinum wire over the flame, so that when it is extinguished by the excess of carburetted bydrogen in the atmosphere, the wire becomes of an intense red heat, affording light enough for the miners to discover their road; and upon arriving at a place where the atmosphere contains less than one fourth of carburetted bydrogen, of itself re-lights the lamp. I am, yours &c. J. O. B.-Norwich. SQUARING THE CIRCLE. Sir,-Permit me to ask, through the medium of the "Mechanics' Magazine," what is the result of the efforts of mathematicians in their endeavours to describe a square equal in area to a given circle. I am aware that the side of such a square has been given in figures, but I have never seen or heard of a geometrical figure possessing any pretence to an approximation to the quadrature of the circle; and should be much obliged by being informed of what has been done. The proportion between the diameter and the circumference in figures is only an approximation, and I wish to know how near geometricians have approached in delineating the desired square; and whether any way of describing a square, which shall be as correct as the arithmetical proportion between the diameter and circumference, is known; and by what process such an approximation can be arrived at upon strict geometrical principles. Your inserting this at your earliest convenience, will oblige a constant reader. M. W. INTERIM NOTICES. S. Toms-Oliver and Boyd, Edinburgh, or Simpkin and Marshall, London. "One of the Stewards" must be one of the greatest fools concerned in the affair. He has sent us a miserable preachment about laudable ends sanctifying any sort of means employed to promote them. Will he give us a plain answer to a plain question? If it is becoming, for the sake of aiding the funds of the Mechanics' Institution, to have a steam-boat benefit, would it be less so were the members to have also a benefit at the Tennis Court? Or if recourse must needs be had to extraordinary expedients for recruiting the funds, why not do something more in character-swallow fire, or send up a balloon? Communications received from Mr. Child-Mr. L.-A. B. C.-J. Walker-R. C. G.-B. D.Amelia-C. C.-A Country Reader-If. 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