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from fths to 1 inch, at the top, except the

of speed.

The general character of the upper plate, which is fths. She is clencher workmanship is very good, and does great built, and double-rivetted throughout. To. credit to the builder. Her exquisite proporwards the extremities, and quite aloft, the tions prevent that appearance of heaviness thicknesses are reduced gradually to 7-16ths. which is generally observable in large ships ;

“ The ribs are framed of angle-iron, 6 and, although she is probably the strongest inches by 3}, by 1-inch thick at the bottom vessel ever built, she has a remarkable air of of the vessel, and 7-16ths thick at the top. grace and lightness.' The mean distance of the ribs from centre to centre is 14 inches ; and all these ribs will How this prodigious floating mass is to be doubled : the distance is then increased be propelled—that is, how the power of to 18 inches, and then gradually to 21 inches the engines is to be made available to the at the extremities.

propulsion of the vessel—is not stated. The boiler platform is of plate iron, We gather only from the breadth assupported upon ten iron kelsons, of which signed for “the beam," and the absence the centre ones are 3 feet 3 inches deep. of all mention of paddle-boxes, that it is These kelsons are formed, like the floorings, not to be by paddle-wheels. of iron plates placed on edge. The hull is

We take our leave of Mr. Grantham divided into five distinct compartments by

with our hearty thanks for the service means of substantial water-tight iron bulk

which he has rendered by his publication, heads. " The decks which are of wood, consist of

not only to the whole ship-building the cargo deck, two cabin decks, and the

craft, but to the nation at large. He is

the first who has set the subject of it # It would be an endless task, and, with fully and fairly before the public; and out the aid of drawings, a fruitless one, to

we venture to predict will do more by his attempt a description in detail of the con little work; to promote the universal struction of this magnificent yessel. I can, adoption of iron in the building of ships, however, state that her lines are very beau than will be effected even by the launchtiful, and adapted to attain the highest rate ing of the Bristol Leviathan.

upper deck.

JONES'S WATER KITES FOR THE PREVENTION OF SHIPWRECK ON A LEE SHORE.

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[Description by the Inventor.) The inventor begs respectfully to call ventor, who has made it his particular the attention of all parties connected with study for upwards of twenty years, to shipping, and the world generally, to the discover by some means or other a plan present inportant discovery. The in to preveni ships being driven on a lee

shore, feels great pleasure, after a variety water kite should be from 100 to 150 of trials and failures, in laying his plans yards long, so as to give as much play as before the public for their inspection; at possible; the size and strength of the the same time, the inventor begs to state, water kites, also the ropes, must be regu: that he does not intend to secure to him lated according to the size of the vessel. self the benefit of his discovery by patent The opinion of the inventor is, that the right, but is anxious to throw open his speed of a steam-ship of 400-horseinvention to all parties who may choose power, with her engines at full work, to adopt it, without any remuneration would be immediately stopped upon the whatever. The prefixed sketches will at same principle ; in fact it is impossible to once give the public an opportunity of calculate the immense weight of fluid the judging of the correctness of his plans. ship would have to pull against. Those who have taken notice of a fish in There is another important advantage a strong current, must have observed that to be derived from the use of these water a fish checks its speed by the expansion kites when vessels are off the land in of its fins against the fluid. It is also foggy or hazy weather ; by using them well known by every person connected the ship would remain stationary, although with shipping, that a small piece of wood in deep water, till the weather became of an angular form is used on board of a clear. A case in point: the Forfarshire ship, for the purpose of giving the rate steam vessel, trading between Hull and at which the ship is sailing, (see fig. 4;) Dundee, ran on the rocks off the Fern this is called the ship's log. This angu Islands, and became a complete wreck, lar piece of wood, and line attached, is during a very foggy night: this accident, thrown into the sea; the bottom part of and many others, might have been prethe wood being made much heavier than vented, had the vessel been provided the top causes the wood to sink perpen with the water kites, and use been made dicularly in the water with a rope fastened of them when the fog first came on. at each corner, which causes the flat part How much safer would it be for captains of the log to face the ship; by this means of ships, in foggy weather, when off the the log, having a body of Auid against it, land, to lose a few hours rather than run remains stationary when the ship is going the risk of so many lives, as well as proat the rate of ten knots an hour. It is

perty! also well known, that unless the small

J. Jones. wooden peg which is placed in the top

Sheffield, May 20, 1842. corner of the log comes out by a sudden jerk of the line, this small piece of wood will require two or three men to pull it

THE SMOKE NUISANCE-ADDRESS AT THE towards the ship. The figures I 2 are MANCHESTER VICTORIA GALLERY - BY upon the same principle of the log, only C. W. WILLIAMS, ESQ. upon an enlarged scale, or I might say (Continued from vol. xxxvi, page 494.) upon the principle of a boy's kite in

Of the modes of estimating the quantity the water reversed; instead of pulling

of heat generated, and which is among the against air, it is pulling against an im. most difficult objects in the course of prac. mense weight of Nuid; there is this dif.

tical experiments, I will explain some of ference, the boy's kite is made of paper, those by which I have obtained my results : and the water kite is made of strong - These are, Ist. The use of copper bars, timber, with strong ropes attached to the one end of which is inserted in the Aues; the sides of the vessel. The water kites other projecting outside, on which a thershould be made heavy at the bottom and mometer is fixed. The use of these is shown light at the top, so as to keep perpen

by an engraving in the Mechanics' Magadicular in the water ; fig. 2 is supposed

zine, No. 971. to be the tail of the kite, 10 feet long,

These bars necessarily give but relative with a buoy made of cork, so as to swim

temperatures; as the heat, influencing the upon the surface of the water, and to

thermometers, has to be transmitted through cause the water kites to rise and fall with

the bars. At the foot of the chimney it was

found that when the bar thermometer indithe inotion of the waves. A small rope

cated 300', the heat within the flue was (fig. 3) is employed to haul the water at least 750°. This fact was ascertained by kites towards the ship horizontally: the means of fusible metals placed within the ropes from the sides of the ship to the flue. 2nd. The use of this series of fusible

one.

Let me,

metals specially prepared by Dr. Kane, and to two distinct periods. At one time it by which a close approximation was had to would have been five per cent, and at another the actual temperature in the interior of the 35 per cent; and this without any alteration flues. 3rd. The aid of a pyrometer, which, in the amount of fuel used or time employed. by a series of metallic expansion bars, indi. The same question was put to Mr. Parkes, cates the absolute heat within the flues, and in reference to the marine boiler, on which thus affording a working point for observa. he experimented: his answer is 47 per cent. tion. As far as belongs to the combustion and in a much smaller boiler, yet it is mani. of the gases in thus preventing the genera fest that this 47 per cent is still much below tion of smoke, the eye alone is a sufficient the true estimate ; for he shows that the es. guide, as it is in testing the perfection of the caping heat was double what it had been the process in the lamps before us; but as re preceding day, when the boiler was tested gards the quantity of heat generated, we under the old mode of furnace. In this must have recourse to other means. In boiler, the increased weight of fuel used, and small boilers the power of absorbing the in the consequent increase in the waste by the creased quantity of heat that is made, is the chimney, was the result of requiring an inmore difficult from the limited absorbing creased quantity of steam, and thus forcing surfaces they present. Let me suppose a the small boiler to do the work of a larger boiler of a given size, capable of evaporating In such cases the ordinary resource is 500lbs. of water into steam in one hour, by what is called forcing the fires. This, how. 100lbs. of coal ;-let me suppose, by the ever, is a manifest misnomer. It is in truth application of an improved process, that an forcing the boiler. By this system of forcing, additional 50 per cent. of heat is generated. which is nothing more than repeated stirring If the boiler be adequate to taking up this and poking, greater heat is produced in the additional heat, 750lbs. of water will be immediate region of the furnace; and hence evaporated.

the received notion, that enlarging the furhowever, suppose, that from its nace increases the evaporation. This may limited extent of heating surface, or other be advisable under the old system, which cause, it was only able to take up one half depends almost entirely on the heat generated such additional heat-say 25 per cent;-in under the boiler, but not as applied to the that case the remaining 25 per cent would new, which distributes the heat uniformly necessarily be lost by escaping through the along the flues. Tredgold observes :-“The chimney. I ask, should we then be justified surface of boiler to produce a given effect in estimating the economy of the new pro must be sufficient to receive the heat which cess of the furnaces by such measure of in will produce the supply of steam ; and, as creased evaporation ? and would it be safe fire or bottom surface is the most effectual, or correct to estimate it at a gain of but 25 that kind of surface should be of sufficient per cent, without also estimating the other area to receive the whole effect of the fire; 25 per cent which was lost, and which, while the flue surface, or sides, may receive under a better arrangement, or a better the effect of the smoke. Hence we have an boiler, might have also been turned to the easy mode of determining the proportions." account of evaporation ? On this subject Again he says—" The flame and smoke the experimental tin boilers, now before you, must be kept in contact with the vessel, as offer a satisfactory illustration. The experi long as it is capable of affording heat.” ments by these, and their varying results, Thus we see Tredgold looks on smoke as are described in the Mechanics' Magazine, inevitable. Had Watt or Tredgold seen a No. 954. We see how the mere change of system by which the evolved gases from a position of the three boilers varies the eva furnace were wholly converted into flame porative results. Here we see the amount and entirely consumed without smoke, as of evaporation is no test, or even approxi. in the lamp, having the fues filled with mation, to the value of any system of im transparent products from that combustion, proved combustion.

would they have continued to speak of exAt the late meeting in this room, the tracting all the heat from the smoke ? or chairman asked Mr. Houldsworth the ques. would Tredgold have committed the great tion, as reported, “What is your practical error of saying, that the flame is limited to conclusion as to the quantity of steam gene six feet from the bridge with coal, and three rated, with respect to the quantity of fuel feet from coke? What would he have said, used?” Had the question referred to the had he witnessed Mr. Parkes's late experi. quantity of heat generated, it would admit ments on a marine boiler, in which the flame of a direct answer. I have already shown, reached to 40 feet, and in which the eye that, had the question referred to the boiler could not be deceived? What would he and furnace now in Fennel-street, I must have said, if I showed him, as I daily see, a have given two distinct answers, as referrible flame of 20 to 25 feet from a furnace sup

plied with coke alone, and never under ten feet in length ?

“ The distance," says Tredgold,“ to which the flame and heated smoke of a fire will extend so as to be effectual, will depend on the draught of the chimney and the nature of the fuel : from three to six feet will be about the range in a well-constructed fireplace, that is, about six feet with coal and a good draught, and about three feet with coke and slow draught. This, of course, will regulate the length of the boiler." Nothing can be more unsound, and contrary to fact, the moment an improved system of admitting air to the combustible gases from which flame is produced, is adopted.

How then are we to account for these erroneous assertions, but by assuming, lst, That he had not witnessed the proper combustion of the gases, which alone produces flame, and that he had not adopted the means of looking into the flues ? That this latter would, however, have been useless without the former, is clear, as Mr. Parkes observes that he could not see a ray of light in the flues under the old system of exclud. ing the air. Mr. Armstrong, following Tredgold, says in his treatise —“We have never seen the flame go beyond the bottom of the boiler." I will show him the flame all round the boiler, as well as along the bottom; and I will do more: I will show him a continuous flame of 10 to 12 feet long from the bridge, at the very moment, and under the exact state of things, when he alleges that there is no flame at all ; and even asserts that the admission of cold air behind the bridge, instead of actually producing that flame, as it does in fact, would so chill down the bottom of the boiler, as to cause the plates to contract, and drag the rivets into holes. This is alleged by him to have occurred in Hamnett's boiler, which, how. ever,

he never saw in action, as there was no means for internal inspection. If it were so, how did it happen that the rivets and seams were also dragged all over the boiler, and even to the crown of the boiler? I am not surprised that such dicta should have been hazarded, so long as there was no means of effecting the full combustion of the several gases evolved from the coal in a furnace, and no means of internal inspection to enable us to see that such was really the fact : but I am surprised that any one, at the present day, with the power of correcting his own erroneous impressions, should persist in upholding the fallacy, and endeavouring to persuade men, against the evidence of their senses, that a flame never extends be. yond the bottom of the boiler when they see it extending above twenty or thirty feet far. ther : or, that when the fuel on the fire is

clear and incandescent, there is then no gas passing off and no demand for air, while, under such circumstances, they see (as stated in Mr. Parkes's report) a minimum flame of ten to twelve feet arising from the carbonic oxide thus generated, and requiring its due supply of air, as the carburetted hydrogen had previously done.

The importance of enlarging the boiler and its heat-absorbing faculty, is fully exemplified in the Cornish boiler. In Corn. wall, they use enormously large boilers, above four or five times larger than are used in this county.

By this means, and by a system of internal flues and enlarged surfaces, a slow and more economic rate of combustion of the fuel is effected in equal times ; for, after all, on this question of time the whole depends. Economy is two-fold, as to the fuel used, and the time employed. If we adopt a slow rate of combustion, (as shown in the table exhi. bited) or have large boilers as the Cornish plan, each square foot of surface will pro. duce less evaporative effect, in any given time, but the quantity will be made up by extended surface. If, however, we have a more active combustion, or a smaller boiler, with less surface, more heat will be generated, in equal times, but necessarily at a sacrifice of greater waste from the increased temperature of the escaping gaseous products by the chimney.

The more active the combustion, the greater will be the ratio of loss arising from the escaping and unemployed heat; first, because the absorbing surface of the boilers are unable to take up all such additional heat in equal times; and, secondly, because the current or draught of the gaseous matter, carrying such heat through the flues, is also increased. In other words, the conducting power of the metal plates and the recipient or absorbing power of the water are not commensurate with the heat-generative power of the furnace and fuel. If then, in any given boiler, we require the largest quantity of water to be converted into steam from a pound of coal, and, without reference to time, we must have recourse to either large boilers or slow combustion: not because slow combustion produces more heat from the pound of fuel, but because it harmonizes more with the nature of the absorbing faculty which the boiler plates possess. Now this question of time is overlooked in practice, though quite as essential in drawing an inference, as the question of fuel used. Tred. gold says, “ It was well remarked by Mr. Watt, that the sole object of the arrangement of his boilers was to economize the fuel as much as possible. It is not the shallowness or depth of the boiler that produces

this effect, but the making of the boilers of engine, as to decide on the merits of a fur. such & shape, that the air which passes nace by calculating the work done by the through the fire should be robbed of almost boiler. The furnace is connected with the all its heat before it can escape." I ask, boiler, as the boiler is with the engine ; but then, why not ascertain how much of the to determine the efficacy of the one by the heat is thus taken up, and how much of it power exercised by the other, would be conescapes ? for the question of economy hangs trary to all sense and science. Now, let us as much on the quantity that escapes, as on see how many circumstances are likely to that which is employed, --influenced, first, interfere with the efficient action of both by the limited absorbing power of the boiler furnace and boiler. plate surface ; second, by the greater quan. Causes Influencing the Quantity of Heat tity of escaping products from the increased Generated.-1. The state of the atmosphere, draught; and, third, by the increased tem five to ten per cent; 2. The fire burning perature of such products. Thus, the quan into holes, or unequally, and not atteuded tity of fuel used will bear a relation to all to-five to ten per cent; 3. Irregular size these terms, and not to the quantity of steam of the coal lump, large and small-two to generated. Nature requires increased sur five per cent; 4. Inattention to removing face or increased time. Two superficial feet the clinkers-five to ten per cent; 5. Variaof absorbing surface, acting for one hour, tions in the dranght and use of the damper ; may be taken as equal to one foot of surface 6. Quantity of air admitted, and mode of for two hours,—the temperature in the fues admission. being the same. A more perfect combus Causes Influencing the Quantity of Steam tion can only be profitably brought into Generated.-1. State of the flues,-clean or action and rendered available by two means, covered with soot; 2. Shape and size of the namely, by extending such surfaces, or by fues ; 3. Extent of flue, or heat-absorbing increasing its heat-absorbing and transmit surface; 4. Quantity of escaping heat, ting quality.

that is, the rate of current ; 5. Temperature i would, then, caution experimentalists, of this escaping heated matter by chimney ; that, in calculating the general economy of 6, Temperature in the flues. any system of combustion in the furnace by Again, what are the terms and circumthe weight of water evaporated, without tak stances which should enter into our calcula. ing into account the quantity lost by the tion in estimating the value or effect of any chimney, and considering that quantity as system, or any particular boiler? They are equivalent to an increased evaporative power, 1. The weight of fuel employed ; 2. The time such a mode of calculation would be decep taken for its combustion ; 3. The quantity tive in every sense. For, suppose 1,000 of heat generated ; 4. The quantity of such units of heat to be generated per second of heat absorbed by the water ; 5. The quantime from one pound of coal, the weight of tity lost and escaping by the chimney, -that water evaporated will depend on the number is, the current ; 6. The temperature of the of those units absorbed by the water. If escaping products ; 7. The weight of water 800 be absorbed, 200 will be lost; if 500

evaporated. only be absorbed, 300 will be lost; yet In the case of the marine boiler experi1,000 units are generated in both cases. By ments by Mr. Parkes, at times as much as which, then, shall we test the evaporative 40 feet of the fue were filled with flame; and power of the boiler or of the fuel? It is 12 feet of flame was the minimum. The clear that some other test must be supplied flame from coke alone was never less than than the quantity of water evaporated ; yet 10 feet long, and it became 20 feet when the on this item alone do engineers dwell.

fire was urged. Mr. Williams next ex. For my own part, and on that of the plained a table, exhibiting the results of a sounder portion of the inventors, I assert series of minute and careful experiments, that, in undertaking to effect a more perfect made by Mr. Josiah Parkes, on a marine combustion of the gases in a furnace, as we boiler at Liverpool, during the preceding do in the Argand lamp, I do undertake that week. the result will be a great addition of heat ; [We propose giving the Table last al. but I do not undertake that the boiler shall luded to by Mr. Williams, together with give a commensurate increase of steam. To Mr. Parkes's report in our next.] cure the disease of the furnace, does not imply the curing the disease of the boiler. If a physician be called in to cure one

STEAMERS -MESSRS. SEAWARD disease, his success is surely not to be esti AND co's. NEW ATMOSPHERIC ENGINE. mated by the progress of a different one. It Sir,--Having read in your truly esteemed would be just as legitimate to determine the and useful work of the 25th instant, No. efficacy of a boiler by the work done by the 985, an account of the successful trial of a

THAMES

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