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IN TIN AND TINNED VESSELS.

Athens, who has obtained the pure metal by dis- here the comparative safety of the gun cotton with that he believed that the last transit of Mercury

ROYAL ASTRONOMICAL SOCIETY. PLAN OF RUSSIAN BUREAU.

LA

AST Friday evening, at a meeting of the Royal (For Description see previous Page.)

Astronomical Society, at Somerset House, Admiral R. H. Manners, President, occupied the chair. Among the members present were the Astronomer Royal, Professor Adams, Dr. Balfour Stewart, Dr. Warren De La Rue, Messrs. Babbage, W. Huggins, J. Norman Lockyer, C. Varley, J. Buckingham, E.J. Stone, and C. Carrington.

The President, in his opening address for the session, said that the late eclipse in India had been observed most satisfactorily, and that the gentlemen who had been despatched on the mission had fulfilled all expectations in every way, every expedition having been most successful. More especially have the efforts of Mr. Norman Lockyer and

Dr. Janssen been of public value. For many years SMALL OFFICE

past astronomers and physical philosophers have

been examining the constitution of the sun, such, LARCE OFFICE

for instance, as Messrs. De La Rue, Balfour Stewart, Miller, and Huggins; but the grand keystone of the arch has just been put in by Mr. Norman Lockyer and Dr. Janssen. The British Association gave opportunities to their members at Norwich to show what they had done, and many members of the Royal Astronomical Society " came out," including Mr. Burt and Mr. Glaisher, and others, helping in work relating to the moon. He

hoped that the Society would hereafter receive LOBBY

much reliable scientific information from distant parts of the globe. A gentleman told him a few days ago that he was going to establish an observatory at Nankin, in China, and promised to send in some results. Ho (Admiral Manners) thought that perhaps from observatories lying far to the east the Society would in future get interesting accounts of meteoric showers.

Mr. William Huggins, F.R.S. (secretary), then of the Royal Arsenal, Woolwich. As we have reguNOTES ON RECENT SCIENTIFIC DIS- larly laid before our readers the progress of dis- read two reports of observations of the eclipse made

COVERIES AND THEIR PRACTICAL AP-covery with this important explosive, we need only by captains in charge of ships belonging to the PLICATIONS.

recal the last stages—the preservation from decom- Peninsular and Oriental Steamship Company. PURE SILVER AND ITS PROPERTIES—A NEW DIS- position by the use of a weak alkali, and the employ: transit of Mercury across the disc of the sun, COVERY WITH GUN COTTON—THE USE OF LEAD ment of compressed charges. mentioned form, we have said that gun cotton,

which transit had a special value to astronomers, MET ETALS are rarely seen in a state of absolute lighted by an ordinary fuse, has about six times because an accurate timing of the contacts by good the destructive force of an equal weight of gun

observers gives data for more exact computations purity, and as very small amounts of conta- powder. Blessrs. Abel and Brown, however, after as to the real distance of the sun from the earth. minating substances considerably modify their experimenting with gun cotton saturated with Some future transits of Venus will be more valuphysical properties, and to some extent also their nitro-glycerino, igniting it necessarily with the able in this respect than transits of Mercury, but chemical behaviour, the characteristics of pure detonating fuse, tried the experiment of igniting the movements on such occasions of the latter metals are but little known. Our knowledge of gun cotton alone in the samo way. The results planot presents some peculiar phenomena, and its

transits help to get observers into practice for the silver has recently been considerably extended by haps, greater destructive force than nitro-glycerine. work they will have to do in a few years, when the experiments of Professor Christomanos, of This is a great and valuable discovery, for we have Venus crosses the diso of the sun.

* Professor G. B. Airy, the Astronomer Royal, said tillation. Silver was well known to be volatilo to cerine.

the tremendously destructive powers of nitro-gly

For mining and quarrying purposes it had been botter observed at Greenwich than anya a slight extent at very high temperatures, but the removes the only source of danger from the use of where else, for there six telescopes were brought to

bear upon the phenomenon. Mr. Stone was Professor, by the use of a sort of bullet mould made gun cotton, for no hard tamping is necessary. It of well-burnt lime, into which he could direct the is sufficient to fill up the bore with sand. Gun stationed at the great equatorial, a fine instrument,

cotton, as we have recently shown, may be carried driven by good clockwork, and furnished with an flamo of an oxyhydrogen blowpipe, was enabled to and stored with perfect safety from explosion. The object-glass 13in. in diameter. Moreover, it sup, obtain enough of the metal to experiment with. detonating fuse can be inserted in the charge when ports the observer in a comfortable position, and The puro metal he describes as of dazzling white- it is required for use. As with nitro-glycerine, the that is a very great thing. Mr. Stone did not ness. Its specific gravity is 10-575, which is a

explosion of one charge provokes the explosion of attend to time, that work being left to other obanother. Thus, if it were required to de

Just before the last contact he saw the trifle higher than that usually given. It is, of stroy a stoekade, it is only necessary to place phenomenon known as the “ black drop,” in appacourse, easily soluble in nitric acid, and in hot con- the charges at 'distances round the enclosure, direction of the limb of the sun. This phenomenon centrated sulphuric acid. In extremely thin layers and explode one. The osplosion of all follows

is probably caused by irradiation, and he thought it shows by transmitted light a bluish green colour ;

with instantaneous rapidity. Moreover, as said in somewhat thicker, from a yellow to a yellowish above, when the cotton is exploded by the might bo thus explained :—Let B B in the accom

panying drawing be the real brown colour. In the first case, it allows the che- detonating fuse, it is not necessary to confine it.

Bedge of the sun, and let A A be mical rays of light to pass, as the Professor proved Just as with its analogue, nitro-glycerine, the ex

the apparent limb of the sun as in an original way. Chemically pure silver he plosion is so instantaneous that the shattering

enlarged by irradiation. Again, finds is easily soluble in a hot solution of cyanide effects are just as great as when the chargo is

let the outer small circle F be of potassium. When in such a solution, heated to quito exposed. Large blocks of granito, and thick

the true disc of Mercury, and 60 or 70deg. C., a glass rod heated to a somewhat plates of iron have been shattered by exploding

the inner small circle E bo Verhigher temperature is immersed, an uniform layer open charges upon them. A detailed account of

cury as it appears to the eye of motallic silver is deposited, which becomes the experiments made by using gun cotton in this

when diminished in size by irrathicker the longer the rod is allowed to remain in the way is not yet made public; but the discoverers al 18

diation. Now, when the real solution. By filling a test tube with mercury heated will, no doubt, soon supply it.

edge of Mercury touches the real limb of the sun, to 110deg. C., and immersing it for a moment or two A report has been published on the tin and tinned there is not enough light left at that place to proin the solution, a dull white coating of silver was vessels used in the military hospitals in France. duce irradiation because of the cusp that is formed ; deposited on the outside, which on the inside was The metal used for tinning it was found contained consequently, there is an apparent elongation of seen as a brilliant'silver mirror. The tube was then from 25 to 50 per cont. of lead. In vessels re- the planet, as shown at H, and this is the true confilled with equal volumes of hydrogen and chlorine, putedly made of puro tin, the Commissioner found, tact. In past years, people were very much perand carried into (sunlight, whereupon combination in some cases, as much as 15 per cent. of lead. plexed by this phenomenon, and his own early idea and explosion took place. In the case of a tube left Such proportions are dangerous, he says, to on the point was that the observers used very bad in the solution for a longer time for a thicker the public health, and the Government is re- telescopes; but he soon had to give up that theory. layer of the metal, and filled with the same gases, commended to fix a standard allowing only Irradiation is probably a purely ocular phenomecombination only took place slowly and without ex- 5 or 6 per cent. of lead to be used with tin in non, having its seat in the eye itself, and will, plosion. It may be that the mode of silvering glass utensils intended for culinary purposes, or for therefore, be unavoidable to the end of time. In abovo described may be utilized for the silvering of drinking vessels. The author has probably over- 1874 and 1882 there will be transits of Venus, for glass globes and other ornamental objects, which stated the dangers from the use of utensils com- which transits all astronomers should prepare beare now silvered by the somewhat complicated re- posed as he has found ; but it would be well if forehand. It will be important to consider all duction processes.

cheap manufacturers in this country would bear in these things, and to lay down rules as to the chaA great discovery in connection with gun cotton mind that it is not altogether safe to use a large racter and quality of the instruments to be used, has been made by Professor Abel and Mr. Brown, proportion of lead.

and the instructions to be given to the observers.

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servers.

H

nencos.

seen.

sun.

He did not observe the transit of Mercury himself, He did not know whether there was anything of the sun itself was spread out into a nearly conbecause he knew that he had persons about him scientific value in the phenomenon.

tinuous spectrum. younger and better able to do the work. He did The President asked Mr. Lockyer to say a few Professor Adams agreed with the explanation look at the planet while it was on the sun. There words on his rocent discoveries.

given by Mr. De La Rue. is one thing which should be attended to very care Mr. J. Norman Lockyer, F.R.A.S., said that, in Mr. Lockyer said that two slices of light only, fully by astronomers, and that is that all observa- 1866, he communicatod a paper to the Royal one above the other, were admitted through the tions to determine the parallax of the sun must be Society, about the application of spectrum analysis slit of the star spectroscope. One of these, from made when the sun is low down towards the hori- to the determination of the physical constitution the limb of the sun, was spread out into a long zon, and the planet must appear to be on the high of tho solar spots. He succeeded to some extent, broad spectrum, but the other into three or four side of the sun to one observor, and on the low side and then thought that perhaps it was possible to bright lines only. Thus the relative brilliancy of to the other observer, otherwise the measurements esamine by this method the prominences on the the two lines was altered. will not be valuablo. Glass which gives a red tinge limb, without waiting for an eclipse. The means Mr. Stone.—Yes. You disperse one more than is bad in the telescope, because it gives a spectrum. at his disposal wore limited, and the results un- the other. The best thing to reduce the light of the sun he satisfactory. He told Mr. Stone so, who also was Mr. William Huggins said that he had often had thought to be a darkened glass, which gives a green trying the same thing. The Royal Society then a search after the prominences with his spectrotint, since this gives very little of the atmospheric gave him the means to construct a larger instru- scopic apparatus, but without success.

He now spectrum. Would it not be possible to introduce ment, with which, on the 20th of last month, he thought that his spectroscope gave too much disa prism into the eyepiece, and introduce dispersion obtained a sight of the lines of one of the promi- persion for the purpose, for he knew not where to opposite to the atmospheric dispersion ?

About two months before Dr. Jansson did look for the lines, and the apparatus would only The President said that it was a good thing the same in India. On the 5th of November he show a little bit of the spectrum at a time. Inthat Professor Airy came forward, as hitherto (Mr. Lockyer) made a more important observation. stead of using a prism, he once tried the interastronomers had been left much to their own ideas The instrument had then had some improvements position of media to cut off some of the surplus as to the real time of first contacts.

made in it by Mr. Browning, and upon turning it light, and shut out those parts of the spectrum not Mr. James Buckingham, F.R.A.S., said that dur- to th limb of the sun he was surprised to see, wanted. Now they knew where the lines were ing the transit of Mercury ho made fifteen double dire cy he looked through the eye-piece, a phono- situated, perhaps the plan might be of some use. measurements of the disc of the planet. He used me ich somewhat puzzled him. He saw not He found one specimen of dark ruby glass which two telescopes, one with a 9-inch and the other with a lon) ae, but a short one, which appeared to in- cuts off all the rays down to between D and C, and a 21-inch object glass. The planet was considerably dicate a mall prominence, or a loop of a large one which would be very likely to let the line o be smaller than described in the “ Nautical Almanac."

Yet thigh he swept the limb of the sun for some He timed his observations with a chronograph. time, fri a distance of, perhaps, 200,000 miles, he The Astronomer Royal said that he had con

Mr. William Huggins, F.R.S., said that he ob- could nd no large prominence, but still saw sidered Mr. Warren De La Rue's explanation, and served the transit of Mercury with an 8-inch tele- the shr: t lines. He concluded, therefore, that they now thought it quite satisfactory. scope. He saw a bright spot on the planet, which came irom a gaseous envelope of the sun altogether The proceedings then closed. disappeared when Mercury went off the disc of the new to science. He obtained the same results in

If Mercury be surrounded by an atmosphere every part of the limb of the sun, except where turning aside the beams of the sun, it might pro- there were prontinences. Thus is indicated a new duce the effect. Other observers than himself envelope five or seven or eight thousand miles in

MINERALS AND METALS. have seen the bright spot in past years. height, extending all round the sun. There is no

THE production of coal in the United Kingdom Mr. Huggins then read another paper upon old great difference in its thickness at the poles or at transits of Venus.

the equator. The reports from India give three United States is said to be estimated at about Mr. E. J. Stone, F.R.A.S., then made an elabo- lines as those most generally seen.

It was the same 25,000,000 tons. Nearly one-fourth of the coal rate defence to an attack upon a recent paper of with himself. But when the action is excessive he raised in the United Kingdom comes from the his own, wherein he had demonstrated that the sometimes saw a fourth line, near the c of the scale. Durham and Northumberland coal-fields. Thoro times had been made with considerable accuracy, the instrument at the same time as the spectrum duction of coal from them was only 65,394,707 tons. observations of the transits of Venus in former The spectrum of the sun itself is always visible in were 2,871 collieries in the United Kingdom in

1857, and 3,258 in 1867 ; in 1857 the entire probut that astronomers had made gravo errors in of the prominences. their calculations founded upon the observations. Mr. Babbage asked whether an artificial eclipse minerals raised in the United Kingdom in 1867 :

The following statement shows the value of the These errors in calculation were the causes of the of the sun could not be made at will by suspending Coal, £26,125,145; iron ore, £3,210,098 ; tin ore, mistake which had so long prevailed as to the real

some round opaque body in the telescope ? distance of the sun from the earth.

£624,734;copper ore, £699,693; lead ore, £1,158,066; Mr. Newall (who spoke from the midst of a

The Astronomer Royal said he could not under-zinc ore, £41,340; iron pyrites, £67,453 ; gold crowd of members standing in the doorway of the stand why the prominences could not be seen with quartz, 3,241 tons, £5,320 ; nickel ore, £14; arsenic, room), said that he and his neighbours were like out the aid of spectral dispersion. Some years ago, £4,112 ; gossans, &c., £5,808 ; wolfram, £62 ; manShadrach, Meshac, and Abednogo of old, for they when the prominences were a great deal under ganese, £3,232'; barytes, £7,807 ; coprolites, stood at the mouth of a burning fiory furnace. discussion, he told. Mr. Nasmyth his desire to ro- €70,300 ; salt, \£836,963; clays, fine and fire, Would the President act the part of Nebuchad-ceive an image of the sun, in a dark room, upon £589,650 ; earthy minerals estimated £650,000 nezzar and bid them 66

como forth?”

He was sur

a white card. This card was to have a round hole making a total of £34,169,797. The value of the prised that the Royal Astronomical Society could cut in its centre, through which the image of the metals obtained from these ores in 1867 was as not find a room big enough to hold its members.

sun was to pass in a black bag, and the promi- follows :-Iron, £11,902,557; tin, £799,293; copper The President asked Mr. Newall how many

nences, it was hoped, would be seen on the card. £831,761 ; lead, £1,337,509 ; zinc, £79,693 ; silver, members would attend at the next meeting of the Mr. Nasmyth then made him a ball and socket for 895,394oz., £215,400 ; gold, 1,520.z., £5,890 ; other Society? However, they would have a largerroom the telescope, and they fixed their apparatus in a metals, estimated, £15,000; making a total of in time, and near the platform there was plenty of very dark hut. They then let the sun go through £15,187,013. Adding £26,125,145, the value (at room for Mr. Newall and his friends.

the hole in the white cardboard, and he expected the place of production) of the coal raised, and Mr. Newall complained of the horrid ventila- to see red prominences without number upon the £2,167,933 for other minerals not smelted, salt, tion.

white rim to the hole, but could not see one. Yet clay, &c., the total value of the metals and coal and Mr. William Huggins said that there was plenty he could not understand how it is possible to see in 1867 is found to be £13,480,092. In 1866 tho

he thought the conditions were very favourable, and other minerals produced in the United Kingdom of ventilation, only it was not very apparent.

It was below, under the seats.

the prominences with spectroscopic apparatus amount was £41,712,330. A voice wanted to know whether the ventila

-it put him in a great puzzle. He did not say tion was all below, and none at the top ?

this to throw any doubt over Mr. Lockyer's discoThe Secretary then read reports of observations veries. Mr. Stone and himself had resolved to see of the transit of Mercury, as seen in several British to the thing again next summer.

It is reported that the Black Hole of Calcutta has observatories.

Mr. Warren De La Rue said that the difficulty been at length discovered. No one has hitherto Mr. Birt then read a paper on the lunar crater in seeing the prominences arises from the fact that been able to ascertain the exact position of the dun . Linné. astronomers do not throw out the illuminated geon where so many of our countrymen perished in

1756. Conjecture pointed to a spot in the southern The Astronomer Royal said he wished to call the atmosphere of the sun, so h. ve to try to alter the curtain of the old fort of Calcutta, which is now being attention of the Society to a new discovery of the relative brightness of the two lights. In the star pulled down ; and here a space, the exact counterconstitution of a comet by Mr. William Huggins. spectroscope the whole of the rays from the limb part of the Hole, has been discovered by Dr. Norman For the moment he forgot the name of the comet, of the sun are spread out over a large area, whilst Chevers, who has been on the look-out for the place which was a small one, but Mr. Huggins had the rays from the gases are brought together. He for some years. discovered by his spectroscopic researches that it thought that perhaps it might be possible to phocontains carbon in a state of ignition. When he tograph the solar prominences; that the light not

THE MANUFACTURE OF WATCHES AND CLOCKS.

-A most interesting and instructive little work, first heard the fact he thought it quite a new wanted may be sifted away, and the rest allowed thing, and that no meteorite containing carbon had to come through. During the eclipse in Spain the describing briefly, but with great clearness, the rise yet been found. Professor Miller had, however, photographic eye could see what tho human eye been published by Mr. J. W. Benson, of 25, Old told him of four meteoric stones which were found, could not see. Perhaps a thinly silvered glass Bond-street, 99, Westbourne-grove, and the City upon analysis, to contain carbon in vory sensible medium would do to cut off many of the luminous Steam Factory, 58 and 60, Ludgate-hill. The book, quantity. Here, then, is a little further connec- rays.

which is profusely illustrated, gives a full description between the formation of comets and meteors. The Astronomer Royal said that he could not tion of the various kinds of watches and clocks, Mr. Brayley said that many meteors contained

yet comprehend Mr. De la Rue's ex- with their prices, and no one should make a purchase carbon.

planation. If a line A were without visiting the above establishments or consultDr. Warren De La Rue said that he had in his

looked at through a spectrum it would ing. this truly valuable work. By its aid persons possession a piece of meteorite containing carbon.

give, say, for argument's sake, three residing in any part of the United Kingdom, India,

or the Colonies, are enabled to select for themselves Captain Noble, F.R.A.S., wished to call atten

fainter lines, B, In the same way, the watch best adapted for their use, and have it tion to a curious fact. That day was the 13th of

if they observed a flame or promi- sent to them with perfect safety. Mr. Benson, who November-a day on which great meteoric showers

nence, N, it would give, say, three holds the appointment to the Prince of Wales, sends often fell, also a day when a great barometric wave

fainter prominences, T. There- this pamphlet to any address on receipt of two runs up to its maximum. That day the barometer

fore he was still left in the dark.

postage stamps, and we cannot too strongly recomwas at its maximum pressure for the whole month. Mr. Warren De La Rue said that the light from I mend it to the notice of the intending purchaser.

B

000

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SIX-TON PORTABLE STEAM CRANE.

more than the crane deserves to state that during weighted to act as a counterpoise, and to enable

that time, notwithstanding its constant employ- the crane to take the same lift across with as the British Section of the Paris Exhibition ment, it never had the slightest mishap or acci- much safety as in the long way of the carriage. operation an exceedingly weli-arranged portable The crane is mounted on a strong wrought-iron bolted to the carriage ; to the centre of this solesteam crane, by Messrs. Shanks and Son, of Den's carriage with chilled wheels suitable for the plate is fixed a column, around which the crane Iron Works, Arbroath, N.B. This crane was for 4ft. 8fin. gauge. To the sides of the carriage are swings. The framing consists of two sides, beseveral months constantly at work unloading the bolted two strong wrought-iron brackets or wings, tween which are bolted heavy iron frames, which heavy goods in the British Dopartment. It is not between which a platform can be laid, and move round on the central pillar. The boiler,

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tank, &c., are also attached to this framework, and The change from the square to the octagonal shapo scale from the rolling mills at the works--it having. largely assist to counterbalance the load. The jib in the basement is made gradually by stepping boen, in the first place, ascertained that the supply consists of two strong oak boams bound together, tha brickwork at the corners.

of iron scale could be furnished to the contractor the radius of which is adjustable by a worm and It had proviously been ascertained by observa- with sufficient rapidity. The following are approxiwheel. The boiler is multitubular, with an in-vation of the success and failure of actual chimneys, mately the proportions of the ingredients of the ternal fire-box, and contains 162 square feet of and especially of those which respectively stood mortar by measure:heating surface. It is provided with two safety and fell during the violent storms of 1856, that in Lime

2 measures. valves, one of which is locked up; these valves are order that a round chimney in this country may Scale weighted to 60lb. per square inch. The chimney be sufficiently stable, its weight should be such Sand

5 is hinged to the smoke-box to facilitate the clean- that a pressure of wind of about 55lb. per square ing of the tubes. The engine has two cylinders foot of a plane surface directly facing tho wind,

Total Tin. diameter and 10in. stroke. It is fitted with or 27 lb. per square foot of the plane projection of It is scarcely necessary to state that the use of link motion. The valve rods are carried through a cylindrical surface--that is to say, a pressure iron scale for hardening mortar and making it the casing, the extreme ends of the rods working equivalent to the weight of a layer of brick work artificially hydraulic, is familiar to engineers, into brass bushes, which give them a much steadier 3in. deep, and of an area equal to the vertical sec- architects, and builders in Glasgow and its neighmotion when reversing quickly. The crane barrel tion of a round chimney-shall not cause the re- bourhood, but in many other parts of the country is driven by a spur wheel and pinion ; a powerful sultant pressure at any bed-joint to deviate from that process appears to be less known than it friction brake for lowering is also provided, and the axis of the chimnoy by more than one-quarter deserves. The principal constituents of the iron roversing, &c., are conveniently arranged, and of lating according to that principle the thicknesses its action upon lime, and the nature of the artieasy access.

The swinging motion is performed of brick work in the cone were determined to be ficial cement which it forms, have not hitherto, by steam, the arrangement being as follows:-A as follows:

so far as I know, been investigated by chemists. cast malleable worm-wheel is securely fixed to the Uppermost 80ft. of height...

13 brick.

Considering the benefits that have arisen from the bottom of the central pillar, which gears with a Next 80it.

2 bricks. chemical analysis of other comenting materials, worm shaft. This shaft is worked by two wheels, Next

88ft.

2, bricks. it is much to be wished that some chemist should has large bearings, and is otherwise of ample Lowest 2ft., increasing by stops from 21 undertake the examination of this material also. strength. The clutch on the barrel shaft, which to 4 bricks, in order to spread the pressure on the On the top of the chimney is a pitch-coated, is of cast iron, malleable where geared with the basement.

cast-iron curb, lin, thick, coming down 3in. on the spur wheel, makes the crane swing in either direc The bed-joint of least stability is 2ft. above the outside and inside. The lightning conductor is a tion, the motion being altered by the reversing ground line; and the deviation of the resultant copper wire rope, about fin. diameter. It termilever; all the bearings are brass. The pump is pressure from the axis of the chimney at that nates in a covered drain, in which there is always provided with a brass plunger, brass valves, brass joint which would be produced by such a wind a sufficient run of water. feed cock, and is supplied from a tank on the às has been mentioned would be 6ft. 4in., being In the construction of the internal scaffolding foot-plate, the lovol of the water in which is above a fraction of an inch less than one-fourth of the care was taken that the needles, or horizontal the pump, which invariably keeps the latter in outside diameter. The thickness of the arching beams, should be supported wholly by the brickgood working order. All the necessary details to in the openings for flues is three bricks. The work, and not by the upright posts; for great make the engine and boiler complete are pre- following are the intensities of the mean pressures danger has been known to arise from the brickvided. In our engraving, at page 433, separate due to the load on different bed-joints:-* work coming to bear upon the ends of the needles, drawings of many of the details are shown.

Tons on the and through them on the posts, owing to the settle

Square foot.
At 2ft. above the ground line....

ment of the lower part of the chimney. In order 8

that the concrete foundation might have time to In basement at the springing of the arches 3

bardon before being subjected to a heavy load, it CHIMNEY AT THE WEST CUMBERLAND On the upper surface of the concrete...... 2 HÆMATITE IRON WORKS.*

On the ground below

1.6

was made by the Iron Company themselves before By W. J. MACQUORN RANKINE, C.E., LL.D., &c. include the fire-brick lining, whose thicknesses hardening of concrete. The progress of the build

The thicknesses of brickwork already, stated known that intense pressure tends to retard the

the contract for tho chimney was let; for it is HE chimney now to be described presents are as follows:-In the uppermost 160ft. of the is not of any extraordinary size or figuro; but as it basement, and the flue archways, one brick. The not exceeding 6ft. of vertical height per day, the application of cor-fire-brick' lining is bonded with the common brick-builders in the north of England and in Scotland ;

Tenders were taken from a limited number of rect principles and good workmanship to a struc- work in the ordinary way—the only difference and the lowest offer was accepted, being that of ture of an useful and ordinary kind, the publica- being that the fire-bricks are laid in fire-clay and Messrs. William Wilson and Son, of Glasgow. The tion of an account of it may prove serviceable. It the common bricks in mortar. The reasons for work was executed by that firm in a manner that has now (April, 1868), been in operation for about adopting this mode of construction in preference left nothing to be desired. The following were tho eight months, and has withstood the gales of an unusually stormy season. The duty which this First, when the fire-bricks are bonded with the amounts of the estimated and actual cost respecgaseous products of combustion from four blast common bricks to the stability of the chimney; £1,560 ; being at the rate of almost exactly fourchimney has to perform is to carry off the common bricks, they contributo along with the tively:-Engineer's approximate estimate, £1,672 ; furnaces, and from various stoves and boilers that whereas if an internal fire-brick chimney had been are heated partly hy burning the inflammable gas used, an additional thickness of common brick-pence per cubic foot of the whole space occupied from the blast furnaces and partly by coal. The work would have been required in order to give by the building, which is 94,000 cubic feet nearly. total quantity of solid fuel consumed may be esti- sufficient stability to the outer cone); second, inside the chimney, when doing about three-fourths mated at about 104 tons per hour when all the unless the internal chimney is carried up to the of its full duty, is 490dog. Fal.; and the prossure furnaces are at work. of the chimney is the frustum of a cone with a through the explosion of inflammable gaseous mix- of the draught is l_in. of water, which agrees to straight batter.

Underground there is a plinth tures in the space between ; and, third, under the a very small fraction with the pressure as deduced or basement, octagonal outside at the ground line same circumstances there'is also a risk of the theoretically from the temperaturo and tho height and square at the bottom ; cylindrical inside, and cracking of the outer cone at and near tho upper

of the chimney. pierced with four circular openings for flues.' The end of the inner cone through unequal heating which has just been described are nearly tho same

The dimensions and stability of the chimney roason for adopting a straight batter, notwith- at that place. Vertical cracks in a chimney aro with those of the second highest chianney at standing that à carved batter enables certain the more dangerous the higher the level at which St. Rollox Chemical Works, built about ten years theoretical conditions to be more perfectly ful- they occur, bocause the safety of the higher part filled, is that the accuracy of building with a of a chimney depends more on cohesion and less previously, except that in the older chimney the straight batter can be tested at any moment by a glance of the eye without the aid of instruments. cracks take place near the ground, thoy, aro of from foundation to top, the greatest pressure of on weight than that of the lower part. When such joint of least stability is 100ft. above the ground.

In the great St. Rollox chimnoy, 445 ft. high The principal dimensions are as follows:

little or no consequence. The basement is paved wind which can safely be borne is almost exactly

inside with Gin. of fire-brick, rosting on Gin. of the same, viz., 55lb. per square foot of a plane Height above the ground line

250

common brick, which rests on the concrete. Depth of foundation below the ground

The ordinary brickwork is built of white bricks surface, or about 274lb. per square foot of the line (including a layer of concrete 3ft.

The deep)

of very good quality, supplied by the Iron Com- plano projection of a cylindrical surface. 17

pany. It is built in English bond: in the base-bed-joint of least stability is 210it. above the ment there is one course of headers to every two 468ft. high from foundation to top, the bed-joint

ground. In the great Port-Dundas chimney, Total height from foundation to top 267 courses of stretchers ; in the cone, one course of of least stability is 200ft. above the ground; and Insido diameter at top of cono......

headers to every three courses of stretchers. the greatest safe pressure of wind is 671b. per

13 0 at 2st. above bottom of

Strips of No. 15 hoop iron, tarred and sanded, are

laid in the bed-joints of the cone at intervals of 4ft square foot of a plane surface, or 33 lb. por squaro

21 10 of basement

in height, with their ends turned down into the foot of the plano projection of a cylindrical sur

18 10 of archways for flues... 7 6

sido joints. Care was taken to bed the hoop iron face, so that thero it may be considered that Oątside diameter at top of cone........

on the common brickwork, and not on the fire- there is an excess of stability. 15 3

brick lining. at 2ft. above bottom of

The length of hoop iron in oach bed-joint in which it is laid is twice the circum

25 7 Outside dimensions of square

ference of the chimney. In the concrete founda THE ,, Echo," the forthcoming evening paper, to basement

tion, the basement, and a small part of the cone, be published at one hulspenny, will be printed' by 30ft. x 30ft.

the mortar was made of hydraulic lime. Owing two of Marinoni's machines just erected at the Outside dimensions of foundation to an unexpected difficulty in obtaining such lime copies per hour. They are, we believe, the first of

"Echo" office, capable of producing 80,000 perfect on the spot, it had to be brought from a distanco their kind introduced into this country, although course

31 6 x 31 6 Outside dimensions of concreto

at considerable expense ; and, therefore, the mortar they have been used for some time to print - Le foundation

for the rest of the building was made of a very Petit Journal," the halfpenny evening paper of 34 6 X 34 6

pure lime from the immediate neighbourhood, Paris, which has a circulation of over 250,000 copies * Read before the Institution of Engineers in Scotland. / rendered artificially hydraulic by a mixture of iron I per day.

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