120 SINGULAR PHENOMENON-BURSTING OF GAS PIPES. peculiar construction or arrangement of the flues. The main practical consideration, then, in seeking to protect the plates of boilers from overheating, is, that it is not to the fire, or furnace, that attention should be directed, but simply and solely to the nature of the recipient to which the heat is conveyed, for in this will be fourd to rest the whole question of injury. This will be objected to by those who have hitherto anticipated danger from hard firing and incrustation, and the want of due proportions between the fire and flue surface. Yet I state the position broadly, after the fullest investigation and the most conclusive proof, that if we look to the recipient and its heat-absorbing properties, and attend to the interior of the boiler, and preserve all right in these respects, we shall do all that is practicable towards preventing injury from overheating, or what is erroneously termed 'burning the plates." Let us now enquire what are the several recipients of heat which present themselves in ordinary boilers. These are:1. Water. 2. Steam. 3. Air. 4. Deposit crystallized. 5. Deposit uncrystallized. The two latter have already been examined. I have now to speak of the three first mentioned, and this I will do in my next communication. I am, Sir, yours, &c. C. W. WILLIAMS. Liverpool, February 7, 1842. ON EVAPORATION BY CONDUCTION. BY C. W. WILLIAMS, ESQ. Sir, In reply to the observations of your correspondent, C. W., in your last week's Number, suggesting improvements on my mode of increasing the evaporative power of boilers, I fear he overlooks the main object contemplated by me, which is, not to increase the interior heat-distributing surface of a boiler plate, but to enlarge its exterior heatabsorbing surface. In fact, I require no addition to the inner surface; not on account of the difficulty of removing deposited matter, but because the plane inner side of an iron plate is quite sufficient for the transmission and distribution of all the heat that could, by possibility, be re ceived by the plane outer side of such plate. "Ribbed plates," as suggested by your correspondent, certainly have their value in many respects; as where a slower and more uniform absorption of heat by the liquid is advisable, as in some saline, gelatinous, or other bodies; but, with reference to my object, the mere evaporation of water, such I have found in a great degree to be injurious. There are in boilers the two surfaces or sides of a plate to be attended to, namely, the inner, or heat-distributing surface in contact with the liquid; and the outer, or heat-absorbing surface exposed to the fire or flue. Now, I find that the former is adequate, not only to the distribution of as much heat as can be taken up by the latter, (both being plane,) but even to ten times as much. This is the origin of my plan of increasing the evaporative power of a boiler, and which consists in enlarging the outer receiving surface, so as to obtain a larger quantity of heat. With this view, I present to the action of the heated gases passing through the flues of boilers a large additional absorbing surface, and without adding any thing to the interior distributing surface. The use and value of the pins arises from the well-known property of metallic bodies to transmit heat by conduction. These pins I construct from two to four inches in length, beyond which there can be no practical advantage gained. Being now engaged in a series of experiments, on the large scale, on this important subject, I will recur to it on a future occasion. I am, Sir, yours, &c., C. W. WILLIAMS, Liverpool, February 9, 1842. SINGULAR PHENOMENON-BURSTING OF GAS PIPES. Sir, The bursting of water pipes is a subject that has been very fully discussed in your pages, and one that was supposed to be tolerably well understood; but a circumstance has just occurred that appears to distance all our knowledge on this subject. By protecting my water pipes with ashes, as stated at page 19 of your 961st Number, I have preserved them uninjured through the frost; but I have a syphon pipe, leading from my water cis SUGGESTIONS FOR THE IMPROVEMENT OF CANAL NAVIGATION. tern into the garden, with which I took another course. This syphon consists of a piece of halfinch drawn tin tubing, such as is used by gas fitters, 15 feet long and ths of an inch in diameter externally; the longer leg of the syphon is about 8 feet, the short leg about 4 feet in length: the former is led down a brick wall, to which it is lightly secured by wall-hooks; the latter dips into the cistern. At the latter end of October last, before the frost set in, having no further occasion for any water in my garden, I emptied the syphon, but afterwards shut the cockwhich terminates its lower leg. One day, last week, I attempted to refill the syphon by exhausting the air from its longer leg, but failing in this, I began to look for the cause, when, to my great surprise, I found the empty pipe had actually burst about 9 inches above the cock; not a mere slit, but a palpable enlargement of the pipe, and a rupture exactly as shown in the accompanying sketch. The only pressure that I can conceive to have been operating 121 shorter leg, a pressure that would seem to be altogether inadequate to account for the effect produced. We have frequently heard of the bursting of gas-pipes, an idea which I have always scouted, seeing that the pressure within them never exceeds that of an inch of water, and yet this fact has been most confidently asserted as the cause of several destructive fires. It happens unfortunately in these cases, that as soon as the gas becomes ignited at the aperture thus made, the metal is almost instantly melted, and prevents any observation being made. The positive bursting of such pipes, however, under slight pressure, or in consequence of some disintegrating property of the metal of which they are composed, seems to be demonstrated by the fact which I am now describing. The explanation of this phenomenon is of infinite importance to our domestic safety, as proving the liability to accident from this hitherto unperceived cause, and it also becomes desirable to know whether leaden pipes are subject to the same law. The alternate expansion and partial contraction of leaden pipes, is well understood; how far tin may be subject to a like influence, and whether this will go any way towards explaining the phenomenon in question, I leave your better informed readers to explain. Any persons interested in this question are welcome to inspect the ruptured pipe, which shall remain untouched for a week or so. I remain, Sir, Yours respectfully, 29, Alfred-street, Islington, February 3, 1842. SUGGESTIONS FOR THE IMPROVEMENT Sir,-During the rapid progress of railways our canals have been less thought of, but there is no doubt but the present mode of canal conveyance may be much improved. The principal object to be gained is a quicker transit of goods or passengers, which can only be effected by the boats passing along the canals at greater speed and by being less detained at the locks. It is admitted that a boat at a quick speed meets with less resistance than one at a slow speed. We have had reports of several trials of boats being 122 E. A. M.'S NEW THEORY OF THE UNIVERSE. propelled by steam, but we never had a GESTATOR. E. A. M.'S NEW THEORY OF THE UNIVERSE Sir,-In reply to the remarks with which Mr. Pasley has favoured me, I can only say, that I shall always be ready to adopt any term that may be deemed preferable to my own, as soon as I am satisfied that it fully expresses my meaning. In accordance with my theory, the medium of space would consist of a simple medium with solid atoms differently disposed, as explained in your 963rd Number, and that it is only in communication with organic matter that a different disposition of the atoms with the medium occurs. In my first paper I stated that I used the term firmamental fluid to express the original light which was first created, and which required to be re-constructed by the sun to adapt it to the eye. Earth and heaven, in a material view, only mean body and light. As the word light has so many meanings, I chose (perhaps injudiciously) the term firma mental fluid, but with the intenexpress tion to make it understood, that the said fluid was to be found every where, except where interrupted by solid matter. In further illustration of the description of the medium, it may be as well to observe, that the presence of the solid atoms in the medium occasions a denser atmosphere round each atom, so that when they are pressed together they restore themselves to their original distances. The tendency to produce stillness and compactress in the cold medium, and the tendency to promote motion and diffusion in the hot medium, I have, perhaps, improperly designated freezing and heating principles. I am unused to discussion. By a chemical change, I mean a variation in the disposition of atoms, which occasions a variation of sensation. "The friction attendant on life" must surely be an important agent in the conversion of the cold medium into the hot medium. Whether a man be passive as an Esquimaux, receiving his last gulp of blubber from the fair fingers of his lady, or alert as the conductor of a steam train; whether he be simple as a new-born babe, or "wise enough for fools to think him mad;" whether he earn his bread by the spade, or the "frictioning about" of the harlequin, I have not the least doubt that every state tends to the benefit of the whole. As long as he draws his breath, the "friction attendant on life" will perform its office. What, if 800,000,000 of human beings, &c. were destroyed at the deluge; can any one look at a glass of water through the solar microscope, and imagine that this would occasion a scarcity of animal life? A little difference perhaps in the method of performing the same operation. All theories appear easy to the mind that forms them. Mine assigns a purer element for organic nature than exists elsewhere, consequently, a becoming seat for life; while it at the same time converts a condensing power into a diffusive one, the whole being of course in a state of motion. Is this difficult? The machinery of the universe, materially, appears to have been completed on the fifth day; consequently, the existence of man was not necessary to the motions of the solids of the universe. I have neither ambition nor conceit: I am fully aware of the disadvantages un HINDU PROCESSES OF QUARRYING AND POLISHING GRANITE. der which a person resident in the country, without friends whose taste leads them to the same pursuits, attempts to bring forward a subject of so much importance; but as it appears to me to offer a foundation on which many very interesting explanations may rest, I am anxious to have it rightly comprehended, and shall always be happy to discuss any point which may appear to be doubtful, either with Mr. Pasley, or others of your correspondents. I remain, Sir, Your obedient and obliged, February 2, 1842. HINDU PROCESSES OF QUARRYING AND POLISHING GRANITE. [We extract the following interesting description of these processes by Lieut. Newbold, from Minutes, in the Athenæum, of the Transactions of the Asiatic Society.] The most usual mode followed in India is to employ the agency of fire. In this process, the granite rock is covered with dry bushes of the various acacias common on the plains, which are then fired, and kept burning until quite consumed. The intense heat causes a separation or exfoliation of the granite, to the depth, perhaps, of 24 inches, in the centre of the fire, but gradually thinning off towards the edges. The piece thus exfoliated is then detached, by driving in small iron wedges at the extremities, and is finally raised by a powerful lever. Sometimes the rock proves more refractory than usual, and then it is customary to pour cold water upon it when hot, or to drop on the surface a heavy boulder of greenstone or granite. When blocks are required for statuary or mill stones, or for any other purpose where greater thickness than one or two feet is requisite, another process is followed, precisely similar to that employed by the ancient Egyptians in quarrying the granite of Syene. A great number of holes, an inch square, and of different depths, according to the size of the block wanted, are bored in the rock, close to each other, forming a connected chain around the piece to be detached. Each hole is then fitted with an iron wedge, and the whole are simultaneously and unremittingly struck with iron hammers, until their united force overcomes the adhesion of the block. The chisels used in piercing the holes are kept cool, by pouring water upon them while working, as is done in Europe. When long and thinner slabs are required for bridges, pavements, lintels, &c., a third pro 123 cess is employed, combining the principles of the two former. The rock is heated, as in the first mode, and the separation is completed by driving wedges into a chain of holes, as in the second. In this way Lieut. Newbold has seen blocks of 80 feet in length separated. He also observed that the Hindus take advantage of the calorific action of the sun's rays, in promoting the separation of the granite slabs; and that they, therefore, select the hot season for their work. He found the temperature of a rock at Dewanconda to be 120°, while that of the surrounding air was only 100° in the sun, and 95 in the shade. Sometimes they pour cold water into the clefts made by the wedges, which greatly hastens the separation of the block. The polish given to Indian granites is at least equal to what is found in Egypt; and good specimens may be seen in the Mausolea of Golconda, at Bejánugger, Galberga, and many other places in the peninsula. To effect this beautiful polish, two When a flat surface processes are followed. is required, the granite is slightly smoothed and flattened by an iron tool; and is then rubbed with a large and heavy block of granite, hollowed on its under surface, and having the hollow filled up by a mixture of lac and corrundum. The mixture adheres strongly to the stone, which is tightly fixed between two rods. The extremities of these rods form the handles for two workmen, who draw the stone backwards and forwards over the block to be polished, occasionally throwing water on the surface, to prevent the lac from melting. When the piece to be polished is of a more varied form, as a cornice or moulding, or figure, a piece of wood, with the corrundum mixture, or even a lump of the mixture alone, is used instead of the granite polisher. Any one who has seen the process will be strongly reminded of it by the paintings at Thebes, representing sculptors polishing a statue, which are copied by Rosellini, and in Wilkinson's "Ancient Egyptians." Lieut. Newbold mentioned a remarkable fact connected with the granite of India; that much of it was in the form of spheroids and bosses, having a concentric laminar structure, like the coats of an onion, which frequently exfoliated by the action of the air, throwing off curved laminæ of very varied magnitude. This exfoliation of mountain masses produces some of the most picturesque features of the Indian landscape. It is the cause of its singular dome-shaped mountains and mamillary masses, crowned with tors which would in England be considered Druidical. Rough sketches of some of these, from Bellary and Bavagudda, were shown to the meeting, strongly resembling the Cheese-ring and Logan-stone, so well 124 SPECIFICATIONS OF RECENT ENGLISH PATENTS. known in Cornwall. The paper concluded with some account of the uses to which granite is applied in India; and a brief notice of the colossal temples and figures, and of the pillars, obelisks, and bridges of this material existing throughout the peninsula. APPLICATION OF THE ARCHIMEDEAN Sir,-In your last Number, 965, there is an error of the press, of much consequence to my statement. For 1837, read 1827, which was the year in which I presented my Screw, or "Archimedean" Ship Propeller, to the Lord High Admiral, which he thought proper to reject as quite inapplicable. I am, Sir, your obedient servant, THE PECULIAR CASE OF OXYDATION. Sir,-In Number 963 of your valuable Magazine, a "Constant Reader" wishes to obtain some information respecting a peculiar case of oxydation in a carpenter's stove; I beg leave, through your pages, to give him what knowledge I may have upon the subject: When he has covered the carpenter's stove with plank outside of the flanges, leaving sufficient space for sawdust, he finds the stove to be rustedth of an inch. Now, I think that the sawdust must either be damp, when placed between the iron and the plank, or the steam might possibly get through the flanges, and damp the sawdust, which would then oxydise the iron. The insertion of the above will oblige your obedient servant. W. ABSTRACTS OF SPECIFICATIONS OF ENGLISH PATENTS RECENTLY ENROLLED. JOHN STEWART, OF WOLVERHAMPTON, Esq., for certain improvements in the construction of piano-fortes.-Enrolment Office, Jan. 7, 1842. The first of these improvements, which are five in number, consists in forming the frame of metal divided into compartment for the reception of the sounding-boards, which are only connected with the frame at intervals. The second improvement relates to the mode of constructing and applying soundingboards. These sounding-boards, three in number, are denominated the treble, adapted to the smallest partition of the frame; the tenor, occupying the middle compartments, and a size larger than the former; and the bass, which is considerably the largest, and is fitted in the remaining partition of the frame. The third improvement relates to an improved mode of applying the bridges; these are of beech, 4 feet long, and half-an-inch wide at the treble end, gradually widening to three-quarters of an inch at the bass extremity. The bridge is arched into twentyone abutments, each of which rests upon the sounding-board. The pins for the lower frets are placed on the top of the bridge, (which is perfectly straight,) as usual. The fourth improvement consists in a new mode of stringing, by hanging the wires in small slides fixed in the upper edge of the stud-bar, whence the wires are carried to the pins at the lower edge of the bar, forming the upper frets; the strings then pass down to the bridge in the ordinary way, forming angles between the respective pins placed therein, and after passing below the bridge they are hooked upon steel wires ten inches long, twisted double, with an eye at one end and a hook at the other. The eye is attached to one of the screws of the screw-bar after passing the tension-bar; the other end has a strong steel or iron wire hook, to which a string is attached; it is then turned in the usual manner. The fifth improvement consists in applying the action to upright piano-fortes, by placing the action underneath the keys, and causing the hammers to strike the wires in two distinct lines. The first line of hammers begins at the highest treble wire, and proceeds gradually downwards beneath the stud-bar to the centre of the scale. The second, or bass line begins at the usual distance from the feet placed on the bridge, and is progressively carried up in an oblique direction to the last note of the bass. A descending wire, or other appropriate connection is adapted to the end of each key, its length being varied to suit the position in which each particular hammer is required to strike its string. OWEN WILLIAMS, OF BASING-LANE, LONDON, ENGINEER, for improvements in propelling vessels. Enrolment Office, February 4, 1842. The first of these improvements in propelling is carried out in the following manner :-Two cranks on each end of the engine shaft project beyond the sides of the vessel to these cranks two rods are jointed, to the lower ends of which floats or paddle-boards of wood or iron are affixed. Immediately under the crank-shaft are two axes or guides, through which the paddlerods slide freely, the guides at the same time turning in a horizontal direction. These guides act as fulcra, and also regulate the |