Page images
PDF
EPUB

He says :

stances

the allusions which Mr. Bessemer made in his , nufacture of the world. The specimens of metal | These cylinders were drawn from a round castrecent lecture to the difficulties which have produced by his improved processes which were iron ingot of only two inches greater diameter opposed the successful application of his inven- exhibited at the Institution of Civil Engineers than the finished cylinder, and in the precise tion.

on the evening of his lato lecture, and subse- way in which a gun would be treated"; they “The want of success which attended some of the quently at the President's conversazione, deserv- may, therefore, be considered as short sections early experiments was erroneously attributed by some edly elicited much praise, and afforded mani- of an ordinary 9-pounder field-piece. The tenpersons to the “burning" of the metal, and by others fest ground for many of the hopeful statements sile strength of the samples, as tested at the to the absence of cinder, and to the crystalline con made on the first of these occasions, and pub- Royal Arsenal, was 64,566 lbs. per square inch; dition of cast metal. It was almost needless to lished in the abstract lately given in our while the tensile strength of pieces cut from the say that neither of the causes assigned had anything to do with the failure of the process in those cases columns.

Mersey gun gave a mean of 17,550 lbs. longituwhere failure had occurred. Chemical investigation It is a most gratifying thing to know dinally, and 43,339 lbs. across the grain ; thus soon pointed out the real source of difficulty. It was that we have now put into our hands a showing a mean of 17,550 lbs., per square inch in found, that although the metal could be wholly de homogeneous malleable metal which may be favour of the Bessemer iron. For the accuracy of of sulphur and of phosphorus was but littlo affected cast into any desired form, and which leaves these figures Mr. Bessemer is responsible. If it is and as different samples were carefully analysed, it the mould free from cracks, flaws, hard veins, desired to produce ordnance by merely casting was ascertained that red shortness was always pro- &c., and is at the same time of enormous tensile the metal, the ordinary founding process may duced by sulphur when present to the extent of one- strength. Several samples of the Bessemer be employed, with' the simple difference that tenth per cent., and that cold shortness resulted from steel tested in the proving machine at Woolwich the iron, instead of running direct from the the presence of me like quantity of phosphorus uit

: Arsenal bore, according to the reports of Colo- melting furnace into the mould must first be Steam and pure hydrogen gas were tried, nel 'Eardley-Wilmot, R.A., a strain varying from run into the converting vessel, where in ten with more or less success, in the removal of sulphur, 150,000 lbs. to 162,900 lbs. to the square inch, minutes it will become steel or malleable iron, and various fluxes, composed chiefly

of silicates of the and four samples of iron boiler plate from 68,314 and the casting may then take place in the oxide of iron and manganese, were brought in contact with the Auid metal, during the process, and the lished experiments of Mr. Fairbairn, Stafford- tough metal, of from 5 to 10 tons in weight, can

lbs. to 73,100 lbs. ; while according to the pub- ordinary manner. Conical masses of this pure many months were consumed in laborious

and expen shire plates bear only a mean strain of 45,000 be produced at Woolwich at a cost not exceedsive experiments ; consecutive steps in advance were lbs., and Low Moor and Bowling plates a meaning £6 12s. per ton, inclusive of the cost of made, and many valuable facts were elicited." of 57,120 lbs. per square inch. There is also pig iron, carriage, remelting, waste in the pro

Here we are sneeringly told that neither of another fact of great importance, as we are re- cess, labour, and engine-power. These importhe causes assigned by disinterested persons for minded, in a commercial point of view. In the tant facts have been laid, we are told, before Mr. Bessemer's failures in 1856 had anything to manufacture of plates for boilers and for ship- the Government, and their advantages are do with those failures ; and we are further told building the cost of production increases con- stated to be fully appreciated by Colonel Eardthat the true cause was the presence of sulphur siderably with the increase of weight in the ley-Wilmot, the Superintendent of the Royal and phosphorus in the metal produced, the air plate ; for instance, the Low Moor Iron Com- Gun Factories, who has evinced a great interest blast having but little effect upon these impu- pany demand £22 per ton for plates weighing in the progress of the invention from its earliest rities. But what are the facts? One of the 2 cwt. each ; but if the weight exceeded 5 cwt. date. earliest adverse criticisms of Mr. Bessemer's then the price rises from £22 to £37 per ton. paper which appeared was an article contributed Now, with cast ingots such as the one exhibited EXPLOSIONS AT GUNPOWDER to the MECHANICS? MAGAZINE of September 13, which the sample plates were made, it was less It is desirable, we think, before the memory at the Institution by Mr. Bessemer, and from

WORKS. admirable volume on “The Iron Manufacture troublesome, less expensive, and less wasteful of the late fatal explosions at Hounslow passes of Great Britain ;” and in that article the of material, to make plates weighing from 10 to entirely from the public mind, to recur once author distinctly pointed out the fact that Mr. 20 cwts. than to produce smaller ones ; and, more to certain important considerations sugBessemer's process did nothing towards the re

indeed, there was but little doubt that large gested by them. In doing this we will, in the moval of the sulphur and phosphorus from the plates would eventually be made in preference

, first place, revert to the evidence given before metal. “Mr. Bessemer committed a great

and that those who wanted small plates would the Coroner in reference to the late inquiry, mistake,” said Mr. Truran, “when he claimed have to cut them from the large ones. A confining ourselves to the last sitting of the

for his plan the production of that quality moment's reflection therefore shows the great jury. The following are extracts from that “known as charcoal iron, simply from the re-economy of the new process in this respect ; evidence :fining being conducted without contact with and when it is remembered that every riveted

“Mr. Rowse stated that he was about 90 yards off mineral fuel. A superficial acquaintance with joint in a plate reduces the ultimate strength

at the time. It was the lower press exploded first. “ the subject would have shown that the quality of each 100 lbs. to 70 lbs., the great value of Could not say whether the treble dust was brought “ of the fuel used in the manufacture of a long plates for girders and for ship-building into the press-house over night, or whether moro in moiety of the bar-iron, so far as regards the will be fully appreciated.

the morning was taken in a boat; could not say how “usual contaminating ingredients, sulphur and Nor.can we leave this subject without re- pressure is taken off by letting the water off directly.

much there was on the premises the day before. The "phosphorus, has nothing to do with the ulti-ferring, at the risk of repetition, to the wonderful The powder was pressed enough. Takes about five

mate quality of the bar.” And again the promises which the Bessemer process holds out minutes to move the powder from the press. Cannot same gentleman, in an article which appeared in to us in reference to the manufacture of ord- remember how much in the press-house the night the MECHANICS' MAGAZINE of the following nance. Many attempts have been made to before. Might have been fifty barrels. Could not month, said :-" It is questionable if one single produce wrought-iron ordnance, and this object week on the premises.

state there was not eight hundred barrels made per "atom of phosphorus or sulphur was separated has been successfully accomplished in the case “Mr. Ashby, the manager of the works : Had not " [in Mr. Bessemer's experiments), for the re- the large gun produced at the Mersey forge. any farther information to give as to the cause of the "sults of analysis are altogether against a more But, however perfect this one gun may be, the accident. Was now constructing the press in a very “ favourable conclusion. Phosphorus and sul- time required to make it, and its immense cost, with 20 feet of earth over. This wall or fence to be “phur exist to the extent of 14 per cent in manifestly renderit still, as Mr. Bessemer stated, between the press-house and the place where the men many pig-irons, and their removal is essentially a great desideratum to produce guns rapidly and would work the pumps for the hydraulic pressure.

necessary to the production of good malleable cheaply, of a material equal to, or greater in ten- The new press to carry eight barrels instead of double “ iron.” How Mr. Bessemer could have gone on sile strength than wrought iron, and, if possible, that quantity, as was the case in the late press. pottering at chemical analyses in order to disco- free from the liability

which that material has There was a Government inspection by two military ver facts which a sound practical iron-maker to laws and to deterioration during long expo for Government contracts. Îhe firm had existed 39 was thus clearly placing before him, or how he sure to a welding heat. It is believed that the years. The mills had been in existence one hundred can now have the effrontery to sneer at those Bessemer process supplies this desideratum, as years. Should not have a water-tank over the new who were taking pains to teach him what he masses of cast malleable metal can be produced press-house. Considered it caused the great lateral was so manifestly ignorant of, we are at a loss of ten or twenty tons in weight in a single piece, explosion. It was his decided opinion explosions to conceive.

and two or three such pieces may be conve- mills on the premises by five in the last fifteen years. But while we may look to Mr. Bessemer in niently made by the same apparatus in one Hnd sworn that 400 barrels on an average was the in vain, we fear, for any manly recognition of day. The metal so made may be either soft quantity made on the premises at Twickenham per his own shortcomings, or any grateful acknow- malleable iron, or soft steel. In order to prove week. "Had no reason from subsequent inquiry or ledgement of the aid which others offered him, the extreme toughness of such iron, and the other means to alter that statement. Would not and while we must receive with caution all that strain to which it may be subjected without swear there was not eight hundred barrels per week he comes forward to say in commendation of his bursting, several cast and hammered cylinders exploded after the press-house, there were three men own proceedings, we have no wish to deny that were placed cold under the steam hammer, and employed. The quantity of powder usually there was he has at last done good service to the iron ma- crushed without the least tearing of the metal. I from ten to fourteen barrels. In the green charge,

[ocr errors]

AND

BY

No. IV.

or what was now called incorporating houses, forty- | offices must be a sinecure-perhaps placed under | occurred in January last to the spiral staircase twy pounds of powder only at a time ; forty pounds some comfortable arrangement which makes has effectually crippled, as we lately intimated, being allowed by Act of Parliament, and two pounds things right”-or we should not have had to the resources of the directors. The costly lititwenty barrels at a time. One-third of the powder allude to the contumely with which a Govern- gation of actions on the part of some of the sufglazed at Twickenham works came from the Bedford ment Inspector was treated upon demanding ferers, and the liberal discharge of a fair and iGlls.

admittance at the gates of the works the day humane consideration of the claims of others, "Henry Atlee : Is a glazing man. Had been after the late accident, and whose person was have exhausted the means at the disposal of the much injured. There were one hundred barrels of not even known to the man who had held the directors, and nothing remains but the sale of sometimes there are as many as three or four hundred post of porter for many years.

the premises and their really valuable contents barrels, sometimes only twenty. On the day before Mr. Ashby's statement that the proprietors by public auction. This effort having failed, the explosion he was in the press-house ; saw two of the works had determined upon construct the Institution must be sacrificed, unless another hundred barrels there. Forty-nine barrels had been ing the press in a different manner to carry company can be formed to save it from destrucduring the morning previous to the explosion. Tad eight instead of sixteen barrels, is a tacit ad- tion. This, notwithstanding the information no instructions as to quantity of powder to be in the mission that his own judgment is at variance which we lately published upon this subject, glazing-house at once. Glazed one hundred and with that of his employers. We are still dis- has not, it now appears, been accomplished. It thirty barrels a day in both houses. Three men posed to think that even the raising of the would be a lasting discredit alike to the scientific employed. Sometimes glazed more, sometimes less. mound “ upon transverse arches and rendering taste and moral tone of London if such an InThat was the quantity expected to be done. Worked “it bomb-proof” will not afford sufficient prostitution should be suffered to cease for want of on Sundays as on other days. Quantity of powder tection for the men, unless the conditions of the few thousand pounds which would at once was a hundred-weight at å time. Should return to the Act of Parliament and the presumed regula- reinstate it in its position among the unobjecthe mills when sufficiently recovered."

tions as to the prescribed quantity of powder tionable and popular Lions of the Metropolis. We make no reference here to the evidence to be admitted under the roof at one time be On public grounds we venture to press the of Mr. Taylor, the former engineer to the works, strictly adhered to-bomb-proof not being ne- case of the Polytechnic upon the serious and im-- who left, by his own admission, from his cessarily gunpowder proof. Mr. Ashby's " de mediate consideration of public philanthropists. “conviction that the several alterations at the

“cided impression that explosions are unavoid- No time is to be lost. A few days will either * works were of a most dangerous description" able" we consider a most important and consign the noble premises to mercantile ends, if

- because that evidence, given without solicita injurious admission, since it partly discredits not to objectionable purposes still more at variance tion to many persons ex judicio, does not ap attempts to mitigate or suppress these calami- with the design of the Institution, unless the pear to us to agree with that rendered by him ties; and in the very front of so bold and scientific and religious public interpose their cobefore the Coroner. We will therefore leave mischievous an assertion we have lately had in operation to restore it to its wonted uses. Mr. Taylor out of our future comments, merely largest firms for the

manufacture of gunpowder

our own columns the testimony of one of the reproducing a remark openly made in court; in the world, where, as a consequence of judi

THE CASE OF HENRY CORT, * have been more valuable out of doors than cious forethought, and the adoption of very HIS INVENTIONS IN THE MANUFACTURE "in.” It may appear strange that the im“many improvements,” a fatal accident has not

OF BRITISH IRON. occurred for twenty-five years. This dogged portant portions of the inquiry, as given above, should differ so widely from the accounts which refusal to adopt remedies, for the prevention THOMAS WEBSTER, M.A.,F.l.s., &c., Barrister-at-Law. appeared in most of the daily and other jour conventional term now applied to working men The specifications recently published by Mr. especial hand, and we have great reason to happily it does not, through the merciful in- sioners of Patents, show that the inventive

-is not confined to gunpowder works ; but Wooderoft, under the authority of the Commisconfide in their integrity and truthfulness. It will have been already observed that while extent as it did a few years ago. Perhaps the during the

first half of the 18th century, to the terference of the Legislature, exist to the same genius of the country was directed principally, Rowse could not swear there were not 800 Government will ere long see in the manufac- addition of materials and ingredients, and the barrels made per week, Ashby states there were ture of gunpowder a reason for some change ; and adoption of fluxes for facilitating the melting but 400, but would not say there were not 800; as the conditions of one of its Acts has already and improving the quality of iron. and Atlee gives the quantity glazed as 130 been grossly violated, it needs no extraordi- In 1728 a patent was granted to John Payne on upon Sunday, to 910 barrels per week! Mr. nary: excuse for an immediate and searching for machinery for obtaining motive power by Ashby further states that the greatest quantity We have heard it advanced as a non sequitur and boilers for applying heat ; for improve

atmospheric pressure ; for improved furnaces kept in the corning-house was from ten to to the suggestion that these mills should be ments in the manufacture of iron and salt

. The fourteen barrels. Atlee tells us that forty-nine removed farther from the presence of large improvements in the manufacture of iron are barrels had been moved to the glazing-house communities, that the communities came to the stated in the specification to consist in putting from the corning-house during the morning of neighbourhood of the works and not the works certain ingredients into fusion with pig and the explosion. that forty-two pounds was the quantity, al- and partly false. One set of mills may have sow iron, viz., the ashes of wood and other lowed in the incorporating-houses, according existed one hundred years, but we doubt from iron furnaces and forges, which ingredients to Act of Parliament, and we are left for the whether the other two sets, some mile or two being so put into fusion or melted with pig, moment to infer that the Act has not been

apart, treated with contempt. But Atlee steps into time. And in addition to this question of Sow, or other brittle iron will make the like the last witness's place, and testifies to the fact dates— if there really be anything in it--we finery in common forges, and will render the that one hundredweight at a time was taken maintain that it is only within the last few into the incorporating-houses !

same into a state of malleability, as to bear the Can anything be more lamentable than such / years that by the presence of steam and of stroke of the hammer, to draw it into bars or

huge furnaces, and of the increased number of other forms at the pleasure of the workman. a perversion of truth ? for either these men are mills which are admitted to exist by Mr. Ashby, The specification further states that those or asserting what they know to be contrary and which several tall shafts of modern con other bars being heated in the said melted into fact, or two out of three of them are struction fully identify, these works have be- gredients in a long hole, arch, or cavern, are to apparently ignorant of the most important de

come so formidable and alarming. If, in a tails of their duties, and consequently totally word, we are thus far correct, there is not a

pass, between two large metal rollers (which umfit for the responsible situations they hold. habitation that has been built fifteen or twenty faces), by the force of the engine thereafter de

have proper notches or furrows upon their surIf Atlee is right, what an additional burlesque years, or even less, but what had a locus standi scribed, or other powers, into such shapes or have we here upon " the Legislature.” Driving a coach and six prior to the formation of the bona fide works as forms as shall be required. The engine force through an Act of Parliament is fairly outdone they now exist, and not an inhabitant of such which was to cause the iron to pass through where a hundredweight of gunpowder can so action if there be any virtue in the old notion in a frame in the side of a building, the pressure

dwellings but what would have a just cause for the rollers, consisted of a large vane wheel hung easily blow it to the winds. Will so clear a of the penalty attached to the formation of a of the in-current of air being directed upon the violation of the law as is here shown be per- novel nuisance. mitted to pass unnoticed by the authorities?

extremities of the vanes. It may be presumed We elicit from the evidence the fact that

to have been a sort of windmill, from which no although there exists no official inspector of

THE ROYAL POLYTECHNIC. beneficial result for the purpose proposed could gunpowder works, there are two persons de- It is with the deepest regret we learn the im- be anticipated. This specification is deserving puted to inspect and test the strength of the pending close of the above popular Institution. of notice, as suggesting the use of large metal powder making for the Government. Their I The expenses connected with the accident which I rollers with notches or furrows on their surfaces for bringing the iron, drawn by the force of the tramways between the Severn and different tons as compared with 60 or 70 tons per annum, hammer into bars, into the received shapes and parts of the works. The manufacture of mal- the suggested decrease in the quantity of iron forms; their use would be more analogous to leable from cast iron with pit-coal had been made in the country in 1740 as compared with the use of the old slitting rollers, than to the carried on for upwards of half-a-century* since the quantity made in the time of Lord Dudley use according to the invention of Cort after the its introduction in 1713, under the super- may not be accurate ; calculations made by lapse of more than half-a-century.

intendence of Abraham Darby at Coalbrook competent persons on this basis would lead to The furnaces to be employed, as described in Dale, and technically termed the “ buzzing the conclusion that the quantity must have Payne's specification, consisted of a series of process," was the last of the series of inventions increased. “ arched caverns," from and through which the the subject of letters patent for the conversion However this may be, the quality of the iron fiery particles were to be conducted in success of cast into malleable iron by pit-coal, prior to was not good ; the iron of British manufacture sion by “llew3” to heat the materials placed the puddling process of Cort, eighteen years was used only for common purposes, and was therein. From about this time attention would afterwards, towards which, the use of the rever- not employed in the navy for purposes for appear to have been directed to caverns as a beratory furnace was a step in the right direc- which the quality was a material consideration ; substitute for the hollow fire and blast in the tion.

and in 1784 upwards of 75,000 tons of charcoal reduction of the pig or cast into malleable iron, Patents were granted in 1771 to John Cock-bar-iron was supplied from Sweden and Russia and to the adoption of furnaces closely resem- shutt, for “ making malleable iron directly from for consumption in the naval arsenals and other bling the reverbatory furnace.

the ore in a finery or bloomery,” for “ refining important works. It is highly probable that · In 1761 a patent was granted to John Wood pig iron with charcoal into wrought iron," and specimens of iron of a quality not greatly infor a “ new way of making malleable iron from for a new finery or bloomery,” the invention ferior if not equal to foreign marts were occapig or sow metal, commonly called cast iron." consisting mainly in charging and heating of sionally produced by the skill of British manuThe conversion, after certain preparatory opera- the finery, and in the greater supply of air to facturers working upon some of the suggestions tions, was to be performed in close vessels in the metal than in the common way. In 1783 of the many ingenious men who during the prean air furnace, by the aid of certain fluxes (three nonths after the first of Cort's patents), ceding century and a half had devoted themwhich, with the impurities from slag and the a patent was granted to Peter Onions, for selves to a subject of such increasing national iron being brought into a toughand malleablestate working and refining cast iron, and convert-importance; the materials, the furnace, the is wrought into bars under the forge hammer. ing the same from a Huid state into wrought hammers, the rollers, the blowing apparatus In the next year (A.D. 1762) a patent was from the smelting into another furnace, in which quality suitable for any purpose could be pro

or bar iron,” by running the cast iron direct were in daily use, but the art whereby iron of a malleable iron from cast iron. The cast iron it was subjected to a blast and fire until the duced with certainty by the manipulation of was to be melted in a hearth with a blast

, kind of paste, when it was stirred and again the process whereby such a result was to suc

metal became less fluid, and thickened into a the unskilled artizan was strictly a mystery ; that is, freed

from substances interfering with subjected to the blast, the operation of stirring ceed was not disclosed in any of the specificamalleability, then taken out of the fire, separ the particles of iron cohere, when the workman tions and speculations interpreted by the light

being continued until the scoria separate and tions referred to, however near previous suggesa hollow pit-coal fire, heated by the blast of the collects and gathers them into a lump, and of successful practice may now appear to have apbellows until reduced to a loop or ball of hot after being re-heated to a white heat is taken proached thereto. Such have been the characiron, which was to be drawn out under a forge The treatment of the iron in this second furnace knowledge ; the fragments, so to speak, of many

to the hammer, and forged into malleable iron. teristics of all progress in every department of hammer into bar iron. The specification of Roebuck proposes a combination of the hearth has been supposed to be a near approach to the predecessors are, as it were

, gathered up by with a blast for the melting of the cast iron, and puddling of Cort, but they differ in the material some fortunate successor and combined into å of the hollow pit-coal fire with the blast for the particular of the use of a powerful blast as in system which as a whole constitutes, by the subsequent process of bringing the iron into a the ordinary finery, which was a wasteful and common consent of posterity, a landmark in the mass and state suitable for reduction into bar iron extravagant system, whereas in Cort's system ocean of speculation, and an epoch in the history by the action of the forge hammer. The inven

no blast whatever was used, but the process of the progress of each particular science. The tion of Roebuck has recently been strangely

was to be completed, as will hereafter appear, labours of Henry Cort present such a landmark, confounded with the puddling process, the in- / without requiring any blast by bellows, or cy- and constitute such an epoch in the manufacture vention of Cort more than twenty years afterlinder, or otherwise.

of British iron ; the practice which he introwards; the former invention was probably in- Such appears to be the state of invention and duced, like the substitution of pit-coal, and the tended and may be regarded as an improve- of speculation in this important branch of manu- application of the more powerful blast, conment on the well-known blooming process, which facture prior to and about the time of Cort's in-tinues to the present day substantially the was performed by a blast in a hollow fire, ventions ; the labours of so many ingenious same as adopted at the foundry at Fontley, and whereas Cort's process, known as puddling, is men, some of whom had opportunities of prac- published to the world in 1783 and 1784 by performed without any blast in a reverberatory tising the different processes described in their the specifications of the patents then obtained"; or air furnace.

specifications, must have materially advanced the puddling, piling, faggotting, and heating, This was followed by a patent to John and the ståte of practical knowledge in the manu- without the use of the blast and reduction of Charles Wood in the following year (A.D. 1763) facture of iron, particularly in the direction to the iron by rollers, as practiced at Fontley, still for an invention, described in the specification which their labours were mainly directed, survive and form part of the manufacture, as an improvement on the former patent of namely, the manufacture of bar-iron from pit- whatever additions or alterations may have John Wood, two years before (A.D. 1761), for coal. The successful employment of pit-coal in from time to time been introduced. " making cast iron malleable without charcoal the smelting furnace for the manufacture of or blast in an air furnace." The process de- cast-iron in the preceding century naturally led

MONEY-MAKING AT THE ROYAL MINT. scribed is granulation and melting in close pots to its use and substitution for charcoal in the with a covering of clay, by which the iron be subsequent process of the conversion of cast Tue marking-room by its name conveys no sort comes perfectly tough and malleable, and is to be into bar-iron ; this may have been one cause of wrought under the hammer into half blooms. the reduction in 1740 of the number of furnaces of explanation of the operations conducted within This was followed by a patent to Thomas and using charcoal or wood fuel, inasmuch as those importance to the artistic finish of the coins to iron malleable in a reverberatory or air furnace abandoned by reason of the increased use of the mounted on strong mahogany frames

, and

set in with raw pit-coal only.” The piy iron is to be pit-coal or mineral fuel, of which the supply was motion by straps running over pulleys, and which put into a reverberatory or air furnace, built of so abundant.

are in communication with another line of small proper construction, and without the addition

It is not improbable that the estimate given subterranean shafting, driven by a 20-horse power of anything more than common raw pit-coal, of the number of furnaces in the time of Lord engine. Shopkeepers and others, for the detection and thereby converted into good malleable iron, Dudley is too high, and in 1740 is too low, and of guilty servants, have, ere now, marked pieces of and being taken red-hot from the reverberatory that allowing for the increased yield of furnaces gold and silver, but the marking pursued at the furnace to the forge hammer, is to be drawn working continuously with a constant supply of Mint is, we need not say, for a very different pur

coal over those working intermittently with an pose. The "sized,”-or as they might well be to the will of the . The into bars of various shapes and sizes, according uncertain supply, estimated at from 400 or 420 | named after the judicial ordeal through which

have recently assized blanksare carein the employ of the Coalbrook Dale Company, then under the management of that eminent inaccurate statement in the preceding article, to the effect plied to the attendant markers. • I am obliged to Mr. Norris for calling attention to an fully weighed into this room, and then sup

A bag conman Richard Reynolds, to whom, amongst other that the manufacture of iron with pit-coal at Coalbrook taining 720 oz., or 60 lb. troy of the golden things, is due the credit of first employing iron Dale had been attended with no treat commercial success; pieces" is next emptied into a copper pan placed instead of wood in the construction of rail or ) from its adoption in 1713.

tlent process appears to have been carried on continuously | above one of the machines, and a portion of them

No. IV.

are made to fall into, and fill horizontally, or snr- gany ranging-tray. This has flutings in it, and appliances. Into one of these sieves our friends face upon surface, a couple of feeding tubes. The when shaken the blanks naturally range them are placed when removed from the bath, and by machine is then started, and straightway the selves on their edges in the futings, and thus friction with the heated sawdust, the workinan in two pieces at the bottom of the tubes are made, render it easy for the worker to take up rouleau charge of the stove soon gets rid of the moisturo by means of a couple of thin sliders, or miniature after rouleau of them for deposition in the anneal. upon their faces. He is not, however, satisfied *shovels," as they are we believe technically called, ing-box. This becomes useful next, and it is of with this. There may be particles of dust adhering to advance froin beneath the tubes. The pieces just sufficient dimensions to receive on their edges, to them, and these must be got rid of. He are at the same time made to revolve-still in a and confortably—that is, without pressing them has at hand a muffle-a kind of coffee roasthorizontal position-between two grooved steel into it-the 2,804 will-be sovereigns. If this ing apparatus made of copper, perforated with cheeks at a requisite distance from each other to rectangular box were too small, the expansion of small holes, and which can be made to revolve administer a considerable amount of pressure to the gold pieces by heating would inevitably cause within hollow heated cylinder of iron. the circumference of the pieces, and, in fact, to it to fly assunder. Therefore it is that room Into this “muflle" he next places the smooth raise a riin or protecting edge upon them at the must be given to allow for their increased bulk. and healthy-looking pieces, and here their expense of their diameters, which are thus les. The 2,804 hard pieces of gold — become hard "drying-out” is soon made complete. Again the gened. The marked blanks, after this squeezing, by compression in the laminating and drawing officer receives them at the scales, divides the are ejected by the action of the machine itself

, operations--safely ensconsed in their boš, are 2804 into the four packets of 701—the journey and fall forward into a basket lined with pig.skin, covered with thick wrought-iron tops, “ to weight notes on the ticket the working loss in and placed to catch them. In the return stroke make assurance doubly sure” that no air shall the various operations, if any there haply beof the sliders they carry two other pieces from oxidize their surfaces, nor cause volatilization, has them replaced in the butcher's tray, and beneath the tubes to the other end of the machine, and with pot clay the joints are plastered over. despatches them to the room in which they are to where a similar amount of pressure is administered A carriage mounted on small wheels is in waiting receive finally the stamp of approbation-tho to them, and they are deposited in the basket at the oven’s mouth to receive the rich freight; portrait and the superscription of our gracious below; this alternate motion is quickly repeated. it does receive it speedily by use of block and fall, Queen-and to become sovereigns themselves. The attendant has to take especial care that the and then the whole is backed into the oven, form. Silver and copper blanks undergo processes after pioces fall flatly into the tubes, and to keep up a ing thus a more expensive pie than poor Soyer or pickling analogous to those described, the silver constant supply, whilst a frequent testing of the Mrs. Smith ever dreamt of. One hour suffices for becoming in appearance "frosted," and the copper work, produced by the aid of a steel gauge collar, the cooking; the box and its contents are brought of a bright salmon colour. Six workmen perform is necessary also. The pieces must be made of to a cherry-red heat, allowed for a short time—a the whole of the duties of the marking, annealing, uniform diameter, or as coin presently they would few minutes—to remain so, and then withdrawn. blanching, and drying-rooms. exhibit palpably the irregularity, and then be The box, removed from its carriage (which awaits, We have thus seen that as there is a difficulty consigned to the melter, a "consummation" not to and speedily receives another pie) is placed in making money outside the Mint, so is there be wished at all, much less “devoutly." These upon the stone floor to cool. While waiting some trouble in money-making within that well. inachines are rapid in their movements, and 240 for its cooling, our readers may be told guarded establishment. As a lady is said once to blanks per minute are consequently thrown into that in the case of silver being operated upon have remarked to an officer who had conducted the basket from each. It must not be supposed in this department, the open pans or boxes her through its various departments, “Well! if that the milling on the edge is given in this way, are used, that metal requiring a different mode of it gives so much trouble to make a sovereign, I'm or at this stage of the process of coining, as treatment, and the time for annealing it being much sure we ought not carelessly to spend it." The many persons imagine. That is, on the con- shorter than that for gold. As regards copper, gold with which we set out from the refinery of trary, as will be shown, one of the last episodes that is baked in copper cylindrical boxes, made Messrs. Brown and Wingrove has now been cast in the gestative history of the sovereign, air-tight, brought to a red heat, and plunged im. into bars, laminated, drawn, cut, weighed or and all other milled coins struck at Tower Hill. mediately into cold water. In each case the metal assized—to coin a new word-marked, annealed The marking gives a plain rim only, and the is softened sufficiently for coining. It is now time, or baked, pickled, bathed, and dried out for object of this is to render it less necessary to put however, to remove the crust of our pie. The lids of stamping, and in this stage of progress space a very heavy strain on the dies afterwards in the the box are accordingly taken off, and it is in. warns us that till next week we must leave it. coining press. The protecting edge of the future verted over a copper dish or tray, which receives It is hoped, moreover, that thus far, at least, our coin is in fact thus raised, and made ready to re. the contents. A workman catches this up, carries readers have tracked us in our march through ceive the ingraiting or beading from the obverse it to a cistern, and transfers the golden discs to a the Mint, and gathered much novel information and reverse dies. As soon as one bag of the cullender resting beneath a water-tap. A forcible from our teachings. seeming shankless buttons have been properly douché bath is now administered to them, and they "marked,” they are returned with the ticket are thus freed from all foreign matter. But another

THEORY OF NAVAL ARCHITECTUKE. - duly numbered - of their weight to their process awaits them—they must be also pickled; bag, and are ready for the following process. for although fire and water have done much to CONTINUING our explanation of the table given

No. VIII. Of course, in describing the progress of one of these purify them externally, they are not

yet sufficiently in our last article, page 299, last vol., we observe that qnantums, we have described that of the whole bright to become honoured with the impress of after the ordinates have been inserted in their batch of gold of which we have been in pursuit, majesty. A cast-iron copper-if we may be per respective compartments, the table may be looked and it may simplify our subsequent revelations if mitted to use an Irishism-lined with lead, and conto that one, quantum we confine hereafter our taining a boiling but weak solution of sulphuric upon as a map on which the elevation of the attention. Leaving, then, our friend the marker acid, awaits in the blanching-room the coming of surface is registered from a fixed level.• We now to his

monotonous duty, we follow the bag in the candidates for sovereignty. They are speedily come to the calculations, and in the first place we question. The officer of the marking, annealing, deposited therein, and a workman by aid of an

will obtain the displacement by "vertical secand stamping branch again verifies, by weighing, ashen pole stirs them so that each individual tions.” Every ordinate is first multiplied by the the quantity received from the machine, and this blank is brought to face the acid. This

pickling number standing at the head of its respective time virtually counts them. He divides them affair is the work of a few minutes only in the vertical column, thus: all ordinates in the first into four parcels of 180 ozs.= 15 lbs. troy, or 701 case of gold and silver, which latter requires a

column, headed keel or 5 W.L., is multiplied by pieces. These parcels are henceforth, when placed stronger solution of sulphuric acid than its richer , those in the second column headed 44 W. L. is in smaller bags, denominated journies-from, as neighbour; whilst plebian copper blanks demand multiplied by 2, and so on for the others. formerly explained, the French word journée, a some hours of rest in a cold mixture of acid and

Let these multiplications be performed for all days of the Norman rule in this kingdom, 701 fore provided for the indulgence of the last-named, shown in the table in large figures ; in practice day's work--and there is no doubt that in the water. A number of pickling troughs are there the vertical columns, and the results inserted

immediately under the respective ordinates, as coins were considered a very good day's work on The pickled blanks of gold are now removed these results are written in red ink, by which the part of King William's minters.

in the cullender, and again a douché bath of water The four journies of gold are now carefully folded is given them. By this time a change has come

means they are very readily distinguished from the

ordinates. This being performed throughout the and placed in a butcher's tray, or a vehicle much over the spirit of their dream. No longer dull resembling that dangerous article, and transferred and spiritless pieces of very suspicious looking columns, we readily see that if we add together to the annealing-room. Here there are eight metal, they appear in their true colours—bright the results in each horizontal column, the sum ovens, each with an iron door fitted with chains and beautiful. The most sceptical would not now

when multiplied by one-third of the interval and counterpoise weights ; and there are in addi doubt their being gold—the brass buttons have semi-area of the corresponding transverse section.

between the horizontal sections will give the tion tables plated with iron, small carriages of apparently been doubiy gilt while in the copper; For example, in transverse section 8 the sum of the latter material, square shallow cast-iron pans They are, however, very wet after their repeated -05, 5:8, 5:7, 15-4, 13-5, 39-6, and 10.0, equal to with shifting covers, open wrought iron pans with baths, whilst it is necessary that, for stamping, 90 05, multiplied by # of 1'5, the common inout covers, copper tubes, pot clay, and other they should be perfectly dry. Provision has been paraphernalia for the carrying out of the baking made for this difficulty. In the next apartment, terval, or 5, gives 45.025 for the semi-area of that

section. business previously adverted to. The oven then, the drying-room, is a drying stove, a cast iron open

These sums of the results of the ordinates it may be imagined, is already heated by means of bed, about seven feet in length and four in widtha Jucke's patent furnace, and there is nothing at a guess-resting upon brickwork, and having a

multiplied by their respective numbers in each bnt to supply it with the rich batch to be acted fire and flue beneath it. This is covered with beechupon. Well, the four journies are now once more wood sawdust--found to answer the purpose the ordinates for the transverse sections ; and those in the

• The figures in the horizontal columus give respectively mixed, and they are placed this time in a maho. best--and has upon it sieves and other such like vertical columns the ordinates for the horizontal sections.

[ocr errors]

ܐ 12

{ baz+8az-a }

12

m

m

;

manner :

horizontal column are placed to the right in the respectively. and the sum of the results, 1832.0, Putting for A, B, and C their values, as given vertical column headed "areas." We must, carried to the left side of the table, will, when by the equations on page 104, the sum becomes however, bear in mind that these quantities are multiplied by 4:2 and 5, give the displacement in

mo

+ not the semi-areas of the several transverse sec. cubic feet for one side of the ship.

+

6 tions; in the present example they are numerically The quantity 1832.0 is the saine as that ob. the same as the complete areas of those sections, tained for the sum of the quantities in the vertical in consequence of one-third of the distance be column headed “ Multiples of Areas.” This shows tween the horizontal sections being d; for multi- that the displacement found by obtaining the areas

mr

54, +8az-az}; plying by this fraetion, the result is one-half the of the horizontal sections, regarding them as ordiarea of the section, and then multiplying by ? nates to a curve which forms the boundary of an which is the area of the part between P, N, and for both sides gives the same number as is found area representing the displacement, is the same P.N., (shaded in the figure). in the column. as that found by obtaining the areas of the vertical

To find the area of the portion contained beTo obtain the displacement from the column sections, regarding these as ordinates to a curve tween the ordinates PzN, and P,N,; we have headed “ areas,” these areas, or areas divided by which forins the boundary of an area also re- only to write a, for a, in the above equation and a constant number, might, as we have before presenting the displacement.

it becomes stated, be represented by the ordinates of a curve, The two results should therefore in all cases be

m 5 the line of abscissæ being the middle line of the identical, or the calculations are incorrect. 'half-breadth plan, and the ordinates placed at the

We have now explained all that is necessary to respeotive transverse sections, the areas of which obtain the displacement of a ship to the load tire curvilinear area is equal to

The sum of these two portions, that is, the en they represent.

water-line. 'i'he area of the figure thus formed will represent at the constructed load water-line, and their

Ships, however, very rarely swim the displacement divided by the constant number, draught of water is constantly altering by the

{ 4a +16a,+}

12 one-third of the distance between the horizontal sections. The quantities in this column must, tion to that variation which arises from altera. consumption and replenishing of stores, in addi.

az + 4a2 + az

3 therefore, be multiplied by the numbers for finding the area by the common rule, standing tions, such as in the equipment for a man-of-war, which is the second rule.

and in cargo for a merchant ship; it is, therefore, opposite to them respectively in the second ver

Rule.-To find the curvilinear area between two tical column, and the results placed opposite to for all draughts of water. This is done by means necessary to find the approximate displacement

equidistant ordinates, such as of the shaded por. them in the adjacent column headed" Multiples

of of a scale of displacement formed in the fòllowing tion of Fig: 15, in terms of three consecutive equi areas.” The sum of all these numbers, in the present case, equal to 1832.0, when multiplied by of zontal sections are found by methods already and the middle ordinate by 8, add the results

T:-The displacements to the several hori. distant ordinates. Multiply the outside ordinate

adjacent to the shaded portion of the figure by 5, the interval between the horizontal sections, or •5, and then by 4.2, one-third the interval between / given, and which will be described; a line is then together, and subtract the other extreme ordinate their vertical sections, giving for a result 3847:2; under side of the keel of the ship; from this point twelfth of the distance between the ordinates,

drawn, and a point in it taken to represent the from the sum; the remainder multiplied by onewill be the semi-displacement of the ship in cubic are set off according to scale the heights of the will give the area required. feet.

several horizontal sections above the under side This multiplied by 2 for both sides gives of the keel; at these heights lines are drawn per

We have already shown that the quantities 7694:4, the displacement in cubic feet for both sides from the L. W. line to upper part of the keel. pendicular to that line; these lines are then 3:6, 55-2, 103-95, 141.5, 171•4, 209-7,and 236-95,

or the sums of the vertical columns of large Were there any portions of the

ship outside the taken to represent tons, and their lengths are extreme sections, these should be calculated by proportionate to the number of tons displacement figures in the table page 299, are the areas

of the several horizontal sections divided by the ordinary rules of mensuration, and added to is then drawn through their extremities, from acertain number; in order, therefore, to find the above result to give the total displacement, which the displacement may be very accurately / the displacement to the 41 W.L. we have In the present example the only portions outside of the extreme sections, are the thin iron found for any draught of water when the plane of only to multiply 3-6 by 5, 55-2 by 8, the sum of

which is 459 6, and subtract 103.95 from it, flotation is parallel to the constructed load waterkeel and the rudder and post, all of which may be line. In order, however, to find the displacement leaving: 355-65 as a remainder; this quantity safely neglected as inappreciable. The cubic feet divided by 35—the number of cubic feet of sea

to the 4: W.L. it will be necessary to deduce a multiplied by one-twelfth of the distance (1.5 ft.) water in one ton-gives 219-84 as the total dis rule for finding a portion only of the curvilinear between the horizontal sections, and one-third the area P, P, N, N, when there are three equidis. 186.7162 for the displacement in cubic feet to the

distance between the vertical sections, gives placement in tons to the load water-line.

tant ordinates (i'ig. 15). To obtain the displacement by “horizontal sec

44 W.L., and the corresponding number of tons is tions," the ordinates in each horizontal column

5.3347. To obtain the displacement to the 4 W.L., are multiplied by the number opposite to it in the

3:6, 55.2, and 103.95 are regarded as the ordinates second vertical column from the left; and the

to a curve, and multiplied by 5, 2, and respecresults placed immediately to the right of the

tively, and then multiplying by the proper proporordinates, written in red ink, and as is shown in

tion of the distances between the horizontal and the table in large figures.

vertical sections, the displacement in cubic feet is Thus:-The ordinates in the horizontal column

found to be 689-535, and in tons 19.701. The 1 are multiplied by 1, those in column 1! by 2 ;

whole of which calculations will be readily made and so forth for all the horizontal columns.

out from the table. In obtaining the displace. When these are completed, the results will form

ment to the 3. W.L. the ordinates 3:6, 55.2, a series of vertical columns; and it will be seen N,

Ng 103.95, and 141:5, are multiplied by 1, 3, 8, and that the ordinates corresponding to any horizontal

1 respectively, in accordance with the third rule section, will have been multiplicd respectively by In our investigations on page 104 we obtained for finding a curvilinear aren; the sum of which the numbers opposite to them in the second ver- by the summation of a large number (2n) of very results or 622.55 when multiplied by the proper tical column from the left; the sum, therefore, of small trapeziums, the area of the entire figure proportions of the distance between the horizontal the results in the vertical columns, when multi- between P, N, and P, Nz; but it is clear that we and vertical sections, will give 1470-7743 for the plied by one-third the interval between the ver- could have obtained any portion of it, such as number of cubic feet displacement to that Line tical sections, give respectively the semi-area of that between the ordinates P, N, and P, N.. equal to 42.0221 tons. the corresponding horizontal sections. Thus, the

In this case we should have n trapeziums to To find the displacement to the 3rd W.L. The sum of these quantities in the vertical column sum, instead of 2n as before taken.

displacement between the L.W.L. and 3 W.L. is headed L. W.L., or the sum of .05, 1.8, 1.9, 5.8, 6:0, &c., 3:8, 4:0, and .05, altogether equal to

Referring to page 104 we find that the sum of found by multiplying 236.95 by 1, 209-7 by 4,

and 171.4 by 1, and adding the results together, 236.95, when multiplied by 4-2 will give the the n trapeziums will be equal to

giving 1247.15; then multiplying in the usual semi area of the load water-section.

A {

+ &c. to n terms } manner, there results 5238·03, which is the These sums for the several horizontal sections,

number of cubic feet displacement between the inserted at the foot of the respective columns, are

L.W.L, and the 3 W.L., and the number of tons 36, 55.2, 103.95, 141:5, 171.4, 209.7, and 236.95, {1+3+5+7+&c. to n terms

in the same is 149:658; this number subtracted and to proceed as before, instead of multiplying

from the total displacement, 219.84, leaves 70-182 each of these quantities by 42 to obtain the semi

Cm3

1° +2° +3*+&c.... + ma } for the displacement to the 3 W.L. area of the sections, we shall regard them as the

The same result would be obtained by making ordinates of a curve, the line of abscissæ of which

= A xm +

Bm?, Cms is the middle line of the body plan, and the posi.

the quantities 3:6, 55.2, 103.95, 141:5, and 171.4, 1+

the five equidistant ordinates of a curve, and find. tions of these ordinates, the intersections of this for all values of 1, and when n is infinitely large, / ing the curvilinear area in the usual way. line by the horizontal sections.

The displacement between the and the These quantities must, therefore, be multiplied it is equal to

2 W.L. is obtained in the same way as that be. by the numbers standing at the head of the ver.

Bm? Cm

1
Am +

since
Zero.

tween the upper part of keel and the 4! W.L.tical columns, viz., by 3, 2, 1, 2, 14, 4, and 1

viz., by multiplying 236.95 by 5, 209.7 by 8, add.

2 3 2n?

FIG.15.

[ocr errors]

N

m m

+
n2 n

m +

n

[ocr errors]

+

+

[ocr errors]

+

=

[ocr errors]
« EelmineJätka »