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fitable. In most of the attempts which had been ferred which, combined with naturally good We cannot give a description of the valve without made the idea had been to construct an iron arin positions for absorbing heat, offered the greatest diagrams, but we may state that the objects of the and hand to hold the chisel, and an iron hammer facility for circulation of the water. The paper invention are to carry off the steam as fast as it is to strike the blow, but the vibration which concluded by remarking that great as had been generated above the pressure the boiler is intended attended this mode caused irregularity in the the progress of late years in the construction of to work at; to be entirely out of the reach or conwork, and a ragged uneven edge on the tooth. steam-engines, and the economical use of steam trol of any one to tamper with or overload it; and The slow speed, too, at which these machines were by working expansively, this had not been accom- to be so arranged that in the event of the water worked rendered them unable to compete with panied by equal progress in the construction of getting low in the boiler, the valve shall blow off hand labour. In the machine invented by M. steam boilers; for, whatever might be the scienti. steam, and avoid the possibility of any explosion Bernot, of Paris, these difficulties were obviated. fic knowledge in the latter branch of engineering, or injury beyond the burning of the plates if more The blow was given by the pressure of a flat steel it was certainly not favourably exbibited in the water be not supplied. spring pressing upon the top of a vertical slide, at generality of boilers in present use. On the con- A vote of thanks was accorded to Mr. Naylor, the lower end of which the chišel is firmly fixed trary, the laws of combustion and evaporation and the sitting terminated, the members proceed. The slide was actuated by a cam, making about seemed generally to have been almost entirely ing to visit Messrs. Marshall's flax-mill, and other one thousand revolutions per minute, thus obviat. ignored, and waste of fuel and rapid deterioration works thrown open to their inspection. In the ing the vibration consequent upon the blow with of boilers had been the natural consequences.-evening of Tuesday a conversazione was held in an iron-mounted hammer. After explaining the Mr. Kitson briefly alluded to the inportance of the Victoria Hall. machine more minutely, by means of diagrams, the subject raised by Mr. Longridge, and said Mr. Greenwood remarked, with regard to the that the time had come when more attention The Second Meeting was held in the Civil durability of the cutting, chisels, that it was ought to be paid to the construction of their Court on Wednesday. Mr. Penn again presided. found that they cut five times as many files as boilers. One great mistake which had hitherto

SUPER HEATING OF STEAM. could be cut by hand, without re-sharpening. In been committed was, that persons purchasing the files cut by this machine the teeth were raised boilers simply fixed the power and the amount per the Application of Super-heated Steam in Marine

The first paper read by the Secretary was " On with perfect regularity, and, consequently, when ton, without reference to the construction. This the file was used, each tooth performed its proper had, commercially, been really a great error, be Engines,” by Mr. J. Penn, the President. The share of work; whereas, in hand-cutting, from cause if greater power were given to the boiler paper was of a technical character, but of great

interest to practical men. The writer stated that the varying power of the muscles, especially maker, and a higher degree of intelligence

an opinion in favour of super-heating the steam towards the close of the day, it was impos. brought to bear on the construction of boilers, the sible to produce such perfectly uniform work. result would be to the benefit of the purchaser.- supplied to steam engines had long existed, and it Every description of round or half-round files After some remarks from Mr. Goodfellow, of Man: might be obtained from this principle, though until was cut by the use of a revolving bed, and chester, with respect to evaporation, the President dividing apparatus for round and hand round files. and Mr. Bastow made a few observations, and the recently but little had been effected in its practical The paper concluded by stating that a manufac. discussion closed.—A vote of thanks was then been first definitely tried by Mr. Thomas Howard, tory employing twelve of these machines had been passed to Mr. Longridge.

of Rotherhithe, about twenty-seven years ago. established at Douai, in the north of France, and

MORRISON'S DIRECT-ACTING STEAM CRANE. Considerable economy was effected, but the another at Brussels. A machice, which had been fitted up in the room, was then put into operation by Mr. Morrison, of Newcastle-on-Tyne, descrip test the experiment properly (though it established

The secretary then read an interesting paper machine was too delicate in its construction to by means of manual power, which, however, could tive

of a direct-acting steam crane invented by the principle), and it was given up. Soon afternot give the full velocity, but notwithstanding that gentleman. For the usual complications of wards Dr. Haycroft, of Greenwich, took up the this the work done was of a very satisfactory ordinary steam cranes, there was in this crane subject, and was convinced of its advantages. The character, the files cut being the full-sized flat substituted a piston with a flexible piston-rod, importance of the principle was first impressed hand files. A discussion ensued, and in reply to working steam-tight through a stuffing-box in upon the writer many years ago, and he became Mr. Fothergill

, Mr. Cowper, and others, Mr. the top of the crane-post, passing over two pulleys, satisfied, from the results of experiment and obGreenwood said that the relative cost of cutting and forming the chain. By this arrangement the servation, that great advantages in economy of the files, as shown by practice at Douai, was as 4d. different movements of the crane were performed fuel might be obtained, the main question to be tain class of work, which left a large margin after with the greatest facility and precision, the lift settled being whether it involved any serious practhe cost of the machine and power in favour

of ing being performed by the admission of the tical objection from complication of apparatus, machine work. As to the durability of the files, linder or crane post to a distance equal to the lubrication of the engine. Recent trials, made on

steam above, the piston forcing it down the cy- risk of derangement and failure, or difficulty in it was decidedly greater than that of ordinary lift required. It would lift 32 feet, swing round, a large scale, led the writer to the following con, one, and the machine

would last as long as oldi- discharge, and swing back to re-load, three times clusions : –That an advantage can be obtained nary complicated machinery. There was no diffi per minute. In other words, it would discharge from the use of super-heated steam, amounting to

three tubs of coal, of 2 tons each, in one minute. an economy of fuel of from 20 to 30 per cent. in culty in cutting round and

half-round.files. There Comparing it with water, taking the latter at a marine engines; that a moderate extent of superwas also an additional advantage in the equality pressure of 60 lbs. per square inch, and steam - at heating enables all the important advantages of of the work obtained. In hand labour it was found 60 lbs., the writer said he had found that the cost the plan to be obtained; and that apparently that the files made in the afternoon were not so good as those made in the morning, the muscles would be 8d. The cost of a machine with boiler from extra wear and tear, risk of failure, compli

of steam was but 4.d. per hour, whilst water nothing objectionable is then necessarily involved becoming relaxed, and the blow, therefore, less and steam-pump would be about 4601.—Some cation of apparatus, or difficulty in lubrication. depth, but no doubt the pitch could be altered if discussion took place with respect to the relative The real advantage in employing super-heating

cost of hydraulic and steam cranes, after which a steam appeared to be in preventing the presence necessary, by making the machine a little more complicated. On the suggestion of Mr. Maudslay,

vote of thanks was passed to Mr. Morrison. of any water in the cylinder of the engine, and Mr. Greaves, who had charge of the machine,

ALLAN'S NEW PRESSURE GAUGE.

ensuring that it should be occupied always by

nothing but pure steam; making it a real steambriefly addressed the meeting. He said that he The next paper read by the Secretary was one engine, instead of one working with a mixture of had been engaged in file-cutting twenty-five years, by Mr. Alexander Allan, on a new pressure gauge, water and steam. In all condensing engines the and he was prepared to state that the machine invented by him. The principle of the gange interior of the cylinder, being open to the con. would cut as good files as could be made by hand, consisted in indicating pressure, either above or denser during half the time of each revolution of if properly attended to. It was necessary, how. below that of the atmosphere, by the more or less the crank, was exposed during that time to the over, that the machine should be fixed, and not compressed or expanded condition of a measured low temp ture of the condenser, or about 125 re-set every half-hour. The President then quantity of air contained within the gauge, This degrees, with a vacuum of 134 lbs. per inch below thanked Mr. Greenwood for his paper, and the was acted upon by the pressure through water or

the atmosphere, or 27 inches of mercury. There discussion terminated.

other fluid contained within a bent pipe, which ECONOMY AND DURABILITY OF STEAM-BOILERS. was attached at one end to the gauge, and at the tion of heat from both the sides and the end of

was, consequently, a rapid absorption and radiaThe Secretary then read a paper by Mr. Long other to the boiler or vessel containing the press the cylinder, thus cooling down the whole mass ridge, of Manchester, on the "Economy and Dura- sure to be indicated. The surface line of the of metal. The steam admitted into the cylinder bility of some classes of Steam-boilers.” The water, as seen in a glass tube attached to the body in the next stroke, at a temperature of 260 deg. paper was of a very elaborate character, requiring of the gauge, indicated the

extent of the pressure, if at 20 lbs. per inch above the atmosphere, a number of statistics and diagrams for its illus. on

a graduated scale.—Several gentlemen ex. coming in contact with these cooled surfaces, tration. With respect to the best sarfaces for pressed their favourable opinion of this gauge, heated them up again, being robbed thereby of a heating, Mr. Longridge said there could be no one of which was exhibited, and a vote of thanks portion of its heat ; and the consequence was the dequestion that horizontal surfaces were the best was passed to Mr. Allan for his paper.

posit of a quantity of water in the cylinder, from for absorbing heat, but unless this heat were car

TASTE'S SAFETY-VALVE.

the condensation of an amount of steam proporried off, and accumulation prevented, the prac- The last paper read was one by Mr. William tionate to the quantity of heat imparted to the tical value of such surface for generating steam Naylor, of London, descriptive of Haste's safety. metal of the cylinder. A portion of this water in would be much impaired, and the plates speedily valve for steam-boilers, which was illustrated by the cylinder might be evaporated again into steam injured. Hence those surfaces were to be pre- a section of the valye, and a number of diagrams. towards the end of the stroke, by carrying the

STEAM CRANE.

expansion of the steam down to a sufficiently low der, and 11 empty carriages, weighing 85 tons, ON THE EARTH'S INTERNAL TEMPERA. pressure: but even then its effective value as steam and going at a speed of 36 miles per hour, was TURE, AND THE THICKNESS OF ITS in propelling the piston would have been lost stopped in 23 seconds, running 220 yards. In re

SOLID CRUST. during all the previous position of the stroke. ply to an inquiry, Mr. Allan said the application Now, if as much heat be added to the steam, by of the break was so regulated as to prevent any If we descend beneath the surface of the earth,

By WILLIAN HOPKINS, Esq., M.A., LL.D., F.R.S. super-heating it before entering the cylinder, as shock. would supply the amount of which it was robbed

and observe the temperature at different depths, by the cylinder, it would remain perfectly dry

it is found that within a depth ranging from 50

The Secretary next read “A Description of a steam throughout its stroke, and not a drop . of Steam Crane," by Mr. J. C. Evans, of London, being affected to that depth by the heat which

to 80 feet, the temperature changes periodically, water would be deposited. believed, was the mode in which the super-heating slay, the President, and others, after which the the earth receives from the sun at different of steam acted in producing a saving of steam, President thanked Mr. Evans for his paper.

seasons of the year. The annual variation, howand consequent economy of fuel, by preventing

ever, becomes less as the depth increases, till at the extensive loss or waste of steam that ordi.

THE PUMPING-ENGINES AT ARTHINGTON, the depth above-mentioned it becomes insensible. narily took plate. The addition off 100 degs. of The proceedings of the sitting were closed by a At greater depths, the temperature is invariable heat to the temperature of the steam insured the description of the pumping-engines at Arthington at each point, but increases with the depth, at the accomplishment of the desired object with steam Water-works, communicated through the Secre- rate on an average of 1° (F.) for a depth of at 20 lbs. per inch, as used in marine engines. tary, but it contained no facts which have not between 60 and 70 feet. The best observations The writer then proceeded into more technical already been made public.-Mr. Anderson then which have been made on this subject are those details, reference being frequently made to the moved a vote of thanks to the President for his in deep mining shafts and deep artesian wells; diagrams, and said, that having fitted the engines conduct in the chair, which was seconded by Mr. the greater depth the more completely do anoof the Peninsular and Oriental Company's steamer Fothergill, and carried by acclamation. At the malous influences counterbalance each other. The Valetta with super-heating apparatus (illustrated close of the meeting the following objects of in- greatest depths at which such observations have by diagrams), the experiments made gave a sav. terest were exhibited for the inspection of the been made in Western Europe, are at Monkwearing of 20 per cent. of fuel. These experiments members : - A steam carriage for common roads mouth and Dukinfield, in this country; the Puit were not complete, but they were entirely satis- at the works of Messrs. Witham, Kirkstall-road; de Grenelle, at Paris ; Mondorff, in the Duchy factory as far as they went.--A very interesting Naylor's steam-hammer, Kirkstall Forge; two of Luxembourg; New Seltswerk, in Westphalia; though technical discussion ensued, in which Mr. locomotive engines, with welded boilers, at the and at Geneva. At the first two places the W. š. Ward, Mr. Morrison, Mr. Cowper, Mr. Midland Station; Aytoun's safety miners' cage, observations were made in vertical shafts of coal Maudslay, the President, and other gentlemen, in a yard opposite to the Town Hall; roof and mines; the depth of the one at Monkwearmouth took part; after which a vote of thanks was | large bell of the Town Hall ; Hattersley's type- being upwards of 1,800 feet, and that at Dunkinpassed to the President for his paper.

composing machine, in the Victoria Hall; and Mr. field upwards of 2,000 feet; and in both cases the SUPPLYING LOCOMOTIVE TENDERS WITH WATER.

James's machine for winding up clock weights, in observations were made while the workmen were

the entrance to the Victoria Hall. The Members sinking the shafts, and with every precaution The Secretary read a "Description of Fryers were taken by special train to the puinping-works against the influence of any extraneous causes Apparatus for Supplying Locomotive Tenders at Arthington, after which they dined together in which might affect the observations. The former with water,” by Mr. James Fenton, of Low Moor. the Wellington Hall

. On Thursday they visited gave an increase of 1° (F.) for every 60 feet of By this apparatus it is proposed to force water Low Moor and Saltaire.

depth, the latter for about every 72 or 73 from tanks below the level of the lines into the

feet. The sinking of the Puit de Grenelle was tenders, by means of the pressure of condensed

superintended by Arago. The mean increase of

THE BRITISH ASSOCIATION. steam from the engines; and it was stated that

temperature was 1° for every 60 feet. At Monthe experiments tried in a large sugar manufactory

ABERDEEN, WEDNESDAY, Sept. 14.

dorff the bore was 2,400, being that of an arteat Manchester had been highly successful. The TIE meeting of the British Association for sian well; the increase was 1° for 57 feet. At New great value of the apparatus was where water 1859 commenced this evening in the new Music Seltzwerk the artesian well, penetrating to the could only be obtained at low levels, and it was hall. There was a very large attendance, and depth of 2,100 feet, giving an increase of 1° (F.) said that there was greater protection from frost, great interest attached to the meeting in conse

for 55 feet. The average of these is very nearly the water being stored below the level of the

1° for 60 feet. Numerous other observations are ground. After a short discussion, in which Mr. quence of his Royal Highness the Prince Consort confirmatory of those results, though observations Fryer explained the apparatus in a more popular being the president elect.

at smaller depths present many anomalies indimanner, a vote of thanks was passed to Mr. Professor Owen, on retiring from the chair, cating the operation of local causes. Fenton for his paper, and to Mr. Fryer for his congratulated the members on the prosperous con

If a sphere of very large dimensions, like the communication:

dition of the Association, and that it was presided earth, were heated in any degree and in any CONSTRUCTION OF STEAM BOILERS.

manner, and were left to cool in surrounding over by his Royal Highness. The Secretary then read a communication from

space, it is shown, by accurate investigation, that

The Prince Consort, after taking the chair, after a sufficient and very great length of time, Mr. B. Goodfellow, Hyde, “On the Construction delivered a very able address, which occupied 40 the

law according to which the temperature would of Steam Boilers."

minutes in delivery, and was loudly applauded increase in descending beneath the earth's surface, IMPROVED RAILWAY BREAK, throughout.

within depths small compared with the earth's The next paper read was by Mr. Alex. Allan,

radius, would be—that the increase of temperature “On Increased Railway Break Power for Stopping

Sir Benjamin Brodie moved, and the Lord Pro. would be proportional to the increase of depth. This Railway Trains." After referring to the im- vost of Aberdeen seconded, a vote of thanks to his coincides with the observed law, if we neglect the portance of increasing the break power for stop- Royal Highness, which was enthusiastically anomalous irregular variations which are found to ping fast trains within a shorter distance than at passed by the large audience.

exist more or less in each locality. Now accord. present, the writer said that the subject of the

FLEET-STREET, THURSDAY AFTERNOON, Sept. 15.

ing to this law, the temperature at the depth of paper was a plan for obtaining increased break

60 or 70 miles would probably be sufficient to repower, by retarding the speed of the engine, by

We confidently expected to receive a report of duce to a state of fusion nearly all the materials means of a throttle valve, placed in the exhaust the Prince Consort's speech from our correspon which constitute the earth’s external solid enve. pipe, which could be instantly closed to any dent in Aberdeen, in time for publication in this lope; and hence it has been concluded, that the required extent, so as to obstruct the exit of the number; but it has not yet reached us, and as we

earth probably consists of a central molten mass steam from the cylinders, the regulator remaining have to publish at noon to-morrow, it is not not more than 60 or 70 miles in thickness : and

as a fluid nucleus, and an external solid shell, of open, at the same time that the exhaust steam was admitted to a small cylinder, the piston of which possible to delay our Magazine further for it.

some geologists, desirous of rendering the concluacted through levers on a break on the engine

sion the foundation of certain theories, have con. wheels. The break cylinder applied the breaks

LIST OF NEW BOOKS.

sidered the thickness even less than that now mensimultaneously to the leading and trailing wheels Brown's Companion to the New Rific Musket, 2nd edit., tioned. of the engine, and the driving wheels were at the

This conclusion, however, rests on reasoning in Burnett's Tillage a Substitute for Manure, 5s. same time retarded by the back pressure of the English Cyclopædia, Knight's Arts and Sciences, Vol. II., which an important element is wanting: It in. exhaust steam on the pistons, consequent upon

volves the hypothesis that the conductive power the closing of the throttle valve in the exhaust Grantham on Iron-ship Building, with vol. of Plates, and of the rocks which constitute the lower portions pipe. The power of the break cylinder was limited, Laurie's Tables of Simple Interest from 24 to 5 per cent., of the earth's crust, is the same as that of the 80 as not to skid the wheels, in order to avoid 24 edit., 21s.

rocks which form its upper portion. This conwearing flat places on the tyres, and to produce Moor's The Ventilation of Mines, 5s. Todhunter's Spherical Trigonometry for Colleges and

ductive power of any substance measures the the greatest effect in retarding the speed. А

Schools, 4s. 6d.

facility with which heat is transmitted through break power of from 14 to 22 tons could thus be

it; and it is easily proved, by accurate investigaobtained by the steam break alone. The retard- THE GREAT EASTERN-Erratum. For the cor- tion, that when the same quantity of heat passes ing power of this steam break had been tried on rection of an error in our last week's article on through superimposed strata of different conducthe Scottish Central Railway with the most satis- this ship, see the first paragraph of our “ Gossip” factory results. A train consisting of engine, ten. of this week.

• Authorised abstract of a recent lecture at the Royal Institution,

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12s.

tive powers, the increase of depth corresponding the pole of the ecliptic with a radius of nearly thickness ?. (and this is the only question of to a given increase of temperature (as l°), is in 23}", equal to the inclination of the equator to geological importance)-Mr. Hopkins denied the any stratum proportional to the conductive the ecliptic, or the obliquity. The whole of this validity of either of the objections above stated. power. Consequently, if the conductive power of revolution is completed in about 25,000 years ; Thus, both the modes of investigation which the lower portions of the earth’s solid crust be but, as follows from what has just been stated, had been described lead to like conclusions respectgreater than that of the thin upper portion of it without any change, beyond small periodical ones, ing the least thickness which can be assigned to through which man has been able to penetrate, in the obliquity. A corresponding change of the solid envelope of our globe. It must be the depth to which we must proceed to arrive at a position must manifestly take place also in the much greater than geologists have frequently certain temperature (as that of fusion for the position of the equinoxes, which have thus a mo- imagined it to be. lower rocks) will be proportionally greater. The tion along the ecliptic in a direction opposite to precise nature of the rocks situated at a great that in which the signs of the zodiac are reckoned, THE NEW CALCUTTA MINT. depth can only be judged' of by analogy completing a revolution in the period above men

THE machinery for the new Calcutta Mint is with those which are accessible to us; but tioned of 25,000 years. It is called the precession rapidly approaching completion, and will be those geologists who adopt the conclusion of of the equinoxes. the extreme thinness of the earth's crust, will This precessional motion has been completely shipped for that place before the end of the year. doubtless admit that its inferior part must be of accounted for under the hypothesis of the earth’s We have no hesitation in saying, after a personal igneous origin, and must therefore be allowed to entire solidity, and that of a certain law according examination of the drawings for the building, and bear a certain resemblance to igneous rocks on the to which the earth's density increases in approach of the various mechanical appliances prepared, or surface of the earth. Mr. Hopkins had recently ing its centre; but some years ago Mr. Hopkins in course of preparation by James Watt and Co., made a great number of experiments on the con investigated the problem with the view of ascerductive powers of various rocks. That of the taining how far the observed amount of precessi

for the establishment, that this new money facsofter sedimentary rocks, which are great absorb. might be consistent with the existence of a fluid tory will, when completed, be the most extensive ents of water, is very much increased by the nucleus. The result was, that such could only be and perfect in the world. The designers of it, it quantity of moisture they contain; but taking the case provided the thickness of the solid shell is true, have had the advantage of inspecting all chalk, one of the best absorbents, its conductive were much greater than that which, as above existing mints, and thus the opportunity of impower, even when saturated, is not half so stated, has been supposed by many geologists. great as that of some of the igneous rocks The numerical result was, that the least admissible proving upon them. They have used that advanon which Mr. Hopkins had experimented. Cal- thickness of the crust must be about one-fifth of tage with extraordinary effect, however, and have careous, argillaceous, and siliceous substances re the earth’s radius; but without assigning any left apparently little for others to improve upon. duced to fine powder, stand, with reference great importance to an exact numerical result, The space of ground upon which the machinery, to their conductive powers, in the order in Mr. Hopkins had a full confidence in the investi on reaching India, will be erected is large, and which they are now mentioned, the conductivity gation, as showing that the thickness of the crust the workshops and offices are in course of rapid of the first being the least; and when in a com could not be so small as 200 or 300 miles, and construction. Two steam-engines of (we believe) pact state, all that contributes to give a hard and consequently that no geological theory can be ad fifty horse-power are intended to give motion to erystalline character to the substance, and con- mitted which rests on the hypothesis of the crust eighteen rolling mills of various sizes, for the tinuity to the mass through which the heat is con- being nearly as thin as it has been frequently breaking down and laminating of silver and gold ducted, increases the conductive power. These assumed to be.

bars. The rollers of these mills are of chilled cast. considerations lead to the conclusion that the con. The influence of the interior fluidity on the iron, the largest being 18 inches in diameter, and ductivity of the inferior portions of the earth’s precessional motion above described, is due to the the smallest 10 inches. There will be eight cutting. solid crust must be much greater, and may be difference between the motions which the attrac out presses of great productive power, from the very much greater, than that of the less consoli- tions of the sun and moon tend to produce on a peculiarity of their make, and the rate at which dated and mere superficial sedimentary beds. solid mass in one case, and a fluid mass on the they will work. What is called the drawbench Moreover, the temperature of fusion of certain other. It has been recently stated, as an objec. will not, as in the British Mint, be used. It is substances, as Mr. Hopkins had shown by ex.

tion to this investigation, that the interior fluid considered that well-finished rolls carefully atperiment, is much increased by great pressure; mass of the earth may move in the same manner tended to, will produce work as accurate as that and by analogy it may be concluded, that such

as if it were solid. The only reply which could which is turned out by this expensive appliance, would, at least in some considerable degree, be the be given to such an objection was, Mr. Hopkins and we have little doubt of the fact. Twelve case with the mineral matter of the earth's crust.

conceived, that it was mechanically impossible coining-presses, made to vibrate at the rate of The chalk is that formation in which the most nu.

that these motions should be the same, though 200 strokes per minute, and to produce coins as merons and some of the best observations on terres, the resulting precessional motion for the solid rapidly, it is said, complete the fitments of this trial temperatures have been made, and it would crust, under certain conditions, to be determined mammoth Mint. The presses are to be impelled seem impossible to conclude from actual experiment only by the complete mathematical solution of by compressed air acting upon pistons attached to and the considerations above stated, that its con. the problem, might be the same as if the whole their fly-arms, and working in iron tubes concenductive power can exceed one-third of that of the

mass were solid.The effect of the attractions of tric with the vertical screw-pin to which the die inferior rocks, and may not improbably be a con

the sun and moon also depends on the ellipticity is attached—an arrangement altogether new in siderably smaller fraction of it. Now the increase of the inner surface of the solid shell; and it has money-making machinery, and now, therefore, to of depth in the chalk corresponding to an increase been said that since that ellipticity depends on the be put on its trial, except as experimentally at of 1° (F.) is well ascertained to be very nearly 60 law of the earth's density, which can only be Soho for the first time. At a further period this feet, and therefore the rate of increase in the in- imperfectly known, no result can be depended on

remarkable work will obtain further attention at ferior rocks must probably be at least three times which involves that ellipticity. This was not

our hands, illustrative as it is of mechanical imas great as in the chalk, and may be very consi.

a correct statement of the problem. It was provement and the march of civilization. derably greater still. Hence, supposing that the assumed in the solution referred to, that the thickness of the solid crust would be about 60 ellipticity of the inner surface would depend

THE GREAT EASTERN, miles, if the conductive power of its lower portion partly on the law of density, and partly on the TO THE EDITORS OF THE “ MECHANICS' MAGAZINE.' were equal to that of chalk, its actual thickness forms of the isothermal surfaces. Mr. Hopkins must probably be at least about 200 miles, and had supposed it possiblo, at the time he was medium of your excellent Magazine to put the

GENTLEMEN,— Will you permit me through the may be considerably greater, even if we admit no engaged in this investigation, that a surface of following question to those gentlemen who are so other source of terrestrial heat than the central equal solidity might approximate to a surface of very confident as to the perfect safety of the Great heat here contemplated.

equal pressure ; he has now experimental reasons Eastern, viz., what will be the effect of and upon There is also another way of investigating the for believing that it must approximate much that noble vessel when her monster engines aro thickness of the earth's crust, assuming the more nearly to an internal surface of equal tem- suddenly and severally released from all resistance whole terrestrial mass to consist of a fluid nucleus, perature. Now, for depths greater, probably by the paddle-wheels and screw becoming alterinclosed in a solid envelope. If the earth were much greater, than those which have often been nately out of water, as inust be the case when accurately spherical, instead of being spheroidal, supposed to correspond to the thickness of the she is resting upon and running directly across its axis of rotation would always remain exactly earth's solid crust, there is no doubt that the and through the crests of water of more than parallel to itself, on the same principle as that on internal isothermal surfaces have a greater ellip 40 feet altitude, or rather, of 80 or 90 feet, which the gyroscope preserves, in whatever posi- ticity than the external surface itself—a conclu- including the depth of the trough of the sea tion it may be held, the parallelism of the axis sion which is independent of the law of density. between them?

W. II. JANES, C.E. about which it rotates. But the attraction of Hence, a like conclusion will hold with reference

September 6th, 1859. the sun and moon on the protuberant equatorial to the internal surface of the shell, it it approxi. portions of the earth's mass causes a progressive mate sufficiently to the surface, of equal tempe SPILL's New MILL-BANDING. Numerons change in the position of the earth's axis, by rature; and this is the conclusion most unfavour- readers having written to us for the adılress of virtue of which the North Pole, or that point in able to the thin shell supposed by some geologists. the manufacturers of the new mill-banding dethe heavens to which the northern extremity of Restricting the interpretation, then, of Mr. Hop- scribed at page 152 of our Magazine for Septeinthe earth’s axis is directed, instead of being kins's results to the question, whether the earth's ber 2, it may save trouble if we mention the stationary, describes a circle on the surface of the solid shell be as thin as some geologists have address here; it is, we believe, Messrs. G. Spill beavenly splere about a fixed point in it called supposed, or at least several hundred miles in and Co., 18 Bread-street, Cheapside, London, E.C.

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LAUBEREAU'S PATENT AIR ENGINES.

FIG.5.
MR. J. LAUBEREAU, Civil Engineer, of Paris, has
just completed a patent for “Improvements in
Air Engines.”

The invention consists in arrangements of ma.
chinery for producing the alternate expansion and i
contraction of air, and in causing the stroke of a
piston to be effected by the expanded air, while
the return is effected by the pressure of the
atmosphere, aided by a partial vacuum obtained
at the back of the piston. The patentee forms a
heating chamber with double sides and communi-, il il the boxes containing non-conducting sub- The working of the engine is as follows :-Firo
cation between them, and by preference in the stances ; ; ;? the cushions or pads ; ;3; the tra being lighted and the piston in the expanding
shape of a n, which is placed in a cylinder or velling cap rods ; j j the external cases containing chamber being drawn up, the cold air is driven
chamber round the upper part of the sides, and at cold water or other cooling agents; k the cylinder; out of the upper part of the expanding and con-
top of which is a chamber for containing cold i the piston travelling in the said cylinder ; l' the tracting cylinder, and simultaneously the air in
water or other cooling agent. In the space piston rod; m the hot-air pipe, the lower extremity the space and the bronze piston between the fire-
formed between the sides of the cylinder and the of which is in direct communication with the hot chamber and side of the cylinder become heated,
sides of the heating chamber, he places a grooved air chamber of one of the generators, and from and the air expanding rushes from the expanding
piston of a n shape, and forms it of some metal which it is conducted into the cylinder at the chamber into the working cylinder, and drives up
of high-heat conducting power, such as bronze. back of the piston ; mi the clack valve admitting the working piston. Immediately before the
This piston is so carried that it does not touch the the hot air, but intercepting the return of the working piston reaches the top of its stroke, the
sides of the cylinder nor of the heating chamber, cold or contracted air ; mo the vacuum pipes com- bronze piston has attained the end of its down
there being space for a thin layer of air between municating from the back of the cylinder to the stroke, and the air in the upper part of the con.
it and them. On the top of this piston he forms cold or condensing chamber k of the same gene- tracting cylinder liaving become cool by contact
a chamber, and fills it with some very bad con- rator ; m' the clack valve, allowing the egress of with the cold sides and top thereof, a partial
ductor of heat, such as lampblack, and again the condensed air; m* the box bolted to cylinder vacuum is formed, and atmospheric air entering
places on the top of this chamber a cushion of bottom, through which the contracted air circu- through openings in the cover of the working
cotton or other like non-conducting material. The lates from the clack valve mo to the pipe mo; n the cylinder by the aid of the pressure of the atino-
piston chamber and cushion are all attached to a connecting rod; o the main shaft and crank ; sphere aided by the partial vacuum, the return
central rod, which works through a stuffing-box P the cam plate keyed on shaft o: pl the cam stroke is effected, and so on successively.
in the top of the cylinder and through the water bolted to the plate p ; p the cam plate or box ;
space. The non-conducting chamber is kept from the vertical oscillating lever ; q' the fulcrum

FIG.1.

FIG.2. touching the sides of the cylinder, a pipe commu- point on which the lever oscillates ; r the rod nicates from the bottom of the cylinder to the connecting the lower extremity of the vertical Working cylinder, in which an ordinary piston is lever to the lever s; s double horizontal lever placed, and conveys the air to and from the work communicating an intermittent reciprocating ing cylinder, and that in which the air is expanded motion to the travelling caps i i; t the fulcrum and contracted. Connecting rods and other agents on which the lever s oscillates ; u u wheels are employed so as to give motion to the piston in attached to the sides of the caps i i, and on which the expanding and contracting apparatus at the they roll in order to diminish the friction ; x a. dead points of the working piston.

hot-air or pressure pipe, the lower extremity of Fig. 1 is a plan of a single-acting engine com. which is in communication with the hot-air plate, and Fig. 2 a sectional elevation. Fig. 3 is chamber of the other generator, and from which a plan of a double-acting engine, the cylinder it is conducted into the cylinder at the front of being removed and one generator shown in sec- the piston; x' a clack valve admitting the hot air,

d tion; Fig. 4 is a front elevation partly in section; but intercepting the return of the cold or contracted and Fig. 5 a section of part of a generator relating air ; z vacuum pipes communicating from the to an improvement in the means of perfecting the front of the cylinders to the cold or condensing

COURT'S PATENT GAS-BURNERS. vacuum. The same letters refer to like parts in chamber h of the same generator, passing through Mr. J. COURT, gas-fitter, of Brompton-row, all the figures. a is the foundation plate; bb are the cooling agent contained in the case j ; 20 a Middlesex, has just patented a very simple but the side frames ; cc are the external cases of fire.clack valve allowing the egress of the condensed useful improvement in those gas-burners which boxes; d d the fire-box covers; e e the smoke air ; x a box bolted to cylinder cover, through have for their objects the better regulating of the pipes ; ff the fire-boxes; 9 9 the hot chambers; which the contracted air circulates from the clack supply of gas to the burner and economy of metal k h the cold chambers; ii the travelling caps ; 1 valve x to the pipes z*.

used in the construction. The invention con.

9.2.

[graphic]

sists in forming a chamber in the nib, and filling. | THE LOSS OF LIFE BY THE WRECK OF sequently sent to institute inquiry into the cause of or partially filling, the same with a number of

THE ALMA.

of the loss of life that has resulted mainly through layers of fine wire, wire-gauze, perforated plates, TO TIE EDITORS OF TUE" MECHANICS' MAGAZINE.” the neglect, moreover, of a brother officer to enforce or other porous material, through which the gas GENTLEMEN, -In your impression of last week proper regulations for its prevention, and which passes. The progress of the gas is retarded and you have again done the State a service in direct- neglect is openly tolerated at head-quarters; I its pressure diminished; it also becomes heated ing publio attention to the sacrifice of life by the ask, is it likely that any punishment will follow? in its course through the nib, and more complete wreck of the Alma through the neglect of the Take a case that occurred some time since within combustion, and cousequently increased illumi- most ordinary precautions for its preservation at sight of our shores. One ship ran into another, nating power, are the results. He forms the sea, and in consequence of which some twenty and more than twenty minutes elapsed before the chamber either by boring the nib at the bottom human beings who might be still living have been disabled one sunk, and seventy people were in of sufficient capacity to receive the layers of wire wantonly hurried into eternity: In doing this consequence drowned (only one boat having been or other material, and he then inserts a plug you again assert for suffering humanity its made available in that time); yet a simple com. (previously drilled through for the passage of the right to protection from those whose duty ment that “it was a common thing for ships to gas) in the bottom of the nib, which presses on

and position in the social scale constitute them carry their boats in-board," was all theofficial notice the material so placed, and confines it in position. its custodians and not its destroyers ; and taken of as wanton an instance of wholesale man; Or the nib is first bored from the top, and after the remedy you suggest of putting captains and slaughter as any that the annals of our criminal placing the material in it is held there by the tip officers in charge of ships on their trial for man. records can show. With such a case before us is (which may be of iron, earthen, or glass of the slaughter is the only one likely to induce a better it to be wondered that the game of death goes usual union jet or bat's-wing slit). Fig. 1 of the state of things; for however the recitals of such bravely on, or that such catastrophes as the accompanying engravings is a sectional elevation of catastrophes may excite our feelings, this process Alma's happen thousands of miles away at sea, a nib complete, where the layers of wire gauze 8 of reformation is far too tardy; and the stronger when, under the very eyes of the officers here at are inserted through the top, resting upon a power of the law, and its rigid and certain appli- home, the causes that lead to them are permitted metal ring c; the tip d may rest on the wire cation as you recommend, will be the only check to continue by the Government in spite of all gauze, or the wire gauze may be fixed in position as to the constant repetition of such cases as that of law and justice ? shown by a hollow tool. Fig. 2 shows a sectional the Alma. The dread of imprisonment, and the Other criminals who destroy human life must elevation of another form of nib, a, a is the outer public shame and disgrace that must follow a man pay the penalties for their misdeeds, but your shell in which a cavity b is bored, the upper part of through life (who having fulfilled his term will still owners, your captains, and your officers of ships which may be filled with wire gauze or perforated carry about with him, as it were, his moral ticket drown their fellow-creatures by hundreds, and plate c. One or two metal rings are employed to of-leave), stigmatised as he would be under such boldly stalk about in broad day-light with no keep the wire gauze from shifting, and the whole circumstances as the cause of the death of other punishment than the troublings of conis firmly secured by a screw plug d.

some of his fellow creatures through his wanton sciences which have already had no influence what

neglect, must have its weight. Repeatedly, when ever in guiding them to the just discharge of THE CORT CASE.

going down the river with ships « clearing out,” their duties to their fellow-men. Death caused by We are glad to find that, in accordance with our men on the look-out," as the most forcible they the same in its consequence on its unhappy

have I heard the argument used by pilots to the inadvertency, and death caused by violence, is announcement made a few weeks since, the Cort could advance to make them careful, that “they may victims; and the men who murder their capri case has been taken up by Mr. Cobden, Mr. Fair. be put in prison if any loss of life should happen tain only bring about a like result with the bairn, and their Lancashire and Yorkshire friends. through their neglect of duty.” Already is this captain who drowns his crew through wanton We find that Mr. Fairbairn's late letter to the law enforced in the factory, the mine, and the neglect of the means that might have saved them Times has been made the basis of the new pro- railway, and the speedy punishment that follows in the hour of need. Yet who ever thinks of ceedings, for the carrying out of which a commit.

a guard or overseer when a life is lost through calling to account the latter, whom the law has tee has been formed comprising Mr. W. Fairbairn, carlessness has materially helped to diminish the already stigmatised as criminally liable. Equal Mr. J. Whitworth, Mr. R. Cobden M.P., Mr. T. Bazley, M.P., Mr. J. A. Turner, M.P., and Ivie not the same consequences attach to captains 'no respector of persons. The poor and ignorant

aggregate mumber of casualties. Why should justice should meet out equal punishıneat, and be Mackie, Esq., Mayor of Manchester. The follow and officers in charge of ships ? Nor should this seamen soon find out how the majesty of the law ing statement has been published :

criminal responsibility be limited to them. is vindicated. The little flies are caught, while the “The immediate object of this fund is to co-operate The Lord Chief Justice Clerk, when life was lost big ones break through its meshes that were never with the iron and engineering trades of Great Britain by the foundering of the Orion, on the coast framed for their capture. The blessings of wealth, for the support of the Cort family, consisting of a of Scotland, summed up in these words: “That education, and position in society should teach us son and three daughters, the youngest of whom is seventy years of age. The inventions of Henry Cort any person placed in a situation in which his acts to set an example of obedience to the laws of our for the manufacture of bar iron have reduced the may affect the safety of others must take all pre- country, and not how to break them, more especost of that most indispensable article, during the cautions to guard against the risk to them from cially, where the poor and unprotected are last seventy years, 66 per cent., as compared with the what he is doing; and in the event of loss of life the sufferers. Only let any one who reads previous price of foreign iron. They have for the through any device resorted to for the purpose of this take the trouble to go through our fast twenty-five years greatly economised conveyance economy, &c., grave criminal responsibility would docks and inspect a few ships "ready for sea," he and transportation by railway and steam navigation, arise, as well to the captain who neglected to use need not be long finding thowl pins out, rudders while the iron wire for telegraph conductors could all appliances in his power to keep the boats in with irons broken, and no yoke lines, oars any. not be made without the same inventions. “The total value of cotton goods, thread, and yarn to have supplied sufficient boats in the first instances like these he will find by scores; but one

proper order, as to the proprietor who should fail where, and boats themselves unfit for use. In. ending 1856, allowing for waste in spinning, and de- stance, or refused proper allowance to have them of punishment awarded for death caused through dueting, cost of raw material, according to a table maintained.”

such neglect he must search our naval history in given in the Encyclopædia Britannica, vol. xiv., Now, the Times states that twenty minutes vain to find out. eigth edition, p. 255, amounts

than elapsed after the Alma struck before the first It is a painful reflection that it should be so; £365,000,000 sterling, to pay all other expenses, boat was got out and lowered, and then, that but no regrets will find the remedy. The know; wages, interest, profits, &c. What, then, must bé as there were no thowl pins in it, it was un ledge that punishment by imprisonment would the aggregate value for the last 58 years, which manageable, and twenty lives were lost in conse- follow every case of life lost through wanton neghad not the steam engine been made available for quence. Now, whose fault was it that no efficient lect

, affords the only hope of a change for the betthe purpose, during the whole of this period, by the hand, and no thowl pins in the boat when on the ject by the press that can alone urge on justice to

means of instantly lowering the boats was at ter; and it is the constant agitation of the subinventions of Henry Cort.

“We, the undersigned, strongly recommend this water? Nay more, how is it that the very circular use its sword. Mercy in such cases to the guilty subscription to all who feel as we do, the great value of the Board of Trade to which you draw such pro- is only future death and suffering to the unproof Henry Cort's inventions, not only to the minent attention, “No. 51, 1857," and which I now tected, for sparing justice breeds iniquity. British nation generally for the last seventy years, give in extenso, was in this very case, as it has If those amongst our rulers who preach philanout of materials abundant and previously useless in always yet been, "a dead letter." our native land, and by native labour, but more directs that life-boats shall carryall requisite for benighted niggers, and severe punishment to

That circular thropy and the exercise of the higher virtues to especially as regards the past and future trades of use," and that "surveyors are to refuse delarations the wretches who enslave and destroy them, wonk! Lancashire and Yorkshire.

in future in cases in which the life-boat is in such only throw a few of the crumbs of their surplus (Signed) “IVIE MACKIE, Esq., Mayor. a position as not to be ready for use in an emer- benevolence to the poor British senmen and help,

“RICHARD COBDEN, M.P.
* WILLIAM FAIRBAIEN, F.R.S." gency, or in which efficient means are not pro- less emigrants and passengers, many a home

vided for lowering it safely and expeditiously into would not now be wanting its mainstay and sup:

the water.” When such regulations as this are port; many a widow's heart would have been a The electric telegraph to Melbourne and Adelaide is in constant use, and affords a remunerative revenue officers specially appointed to see them carried its fatherless children; and you, Sirs, and the get

never enforced on owners before the ship sails, by stranger to the misery of a disconsolate hearth and on the Government the absolute necessity of a second out, and the Board of Trade winks at their neral press of this country, might happily have at wire. Wires to Bathurst and to Maitland were in neglect of public duty, is it to be wondered at longer intervals to comment on such sad stories progress, and will shortly convey messages be that the captain does not trouble his head about as "the loss of life by the wreck of the Alma," for tween those important towns and the Australian such things as thowl pins when he is away at sea; the public warning and the public good. metropolis. and is it likely that one officer who may be sub- Sept. 6, 1859

CHARLES CLIFFORD,

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