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STRENGTH OF LEADEN PIPES.

405 ship and elegance of design. It con- it is made widest at the abutments, sisted of three arches, elegantly light from which it contracts towards the in their construction, and was ad- centre. Percy Anecdotes of Industry. mired by all who saw it. Unfortunately a great flood which occurred drifted down a quantity of timber against the bridge. In consequence STRENGTH OF LEAD EN PIPES. of this obstruction to the flood, a thick and strong dam, as it were, was formed. The aggregate of so

[From the Caledonian Mercury.] many collected streams being unable to get any further, rose here to a Some curious and interesting expe. prodigious height, and with the force riments on this point have recently of its pressure carried the bridge en been made by Mr. Jardine, engitirely away before it. William Ed. neer, at the Water Company's Yard in wards had given security for the sta

Heriot's Green, Edinburgh, with the bility of the bridge for seven years;

view of determining accurately the it had stood only two years and a

proper strength or thickness of metal half. Of course he was obliged to

to be given to the pipes intended for

conveying water through different parts erect another; and he proceeded on of the city. This is an important subhis duty with all possible speed. The ject, and one regarding which pracsecond bridge was of one arch, for tical men have hitherto been much in the purpose of admitting freely under the dark. The observations, thereit whatever incumbrances the floods fore, set on foot by this distinguished might bring down. The span or engineer cannot fail to be of great utichord of this arch was 140 feet. its lity, and we hope the particulars of altitude 35 feet, the segment of a

them will be communicated to the circle whose diameter was 170 feet.

public ; for it happens in this, as well

as in many other branches of mechaThe arch was nnisned, but the para- nics, that a few judicious and careful pets not yet erected, when, such was experimeuts, in one or two particular the pressure of the unavoidably pon- instances, are sufficient to comprehend derous work over the launches, that a vast variety of cases which are conit sprung in the middle, and the key tinually occurring in practice. The stones were forced out. This was a strength of pipes, for example, even severe blow to a man who had his those of the same thickness of metal, therto met with nothing but misfor

varies greatly with the calibre of each. tune in an enterprise which was to

The pipe, in fact, becomes weaker ex

actly as its calibre, or internal diameestablish or ruin him in his pro- ter, is enlarged. Hence it is quite unfession. William Edwards, however, necessary to make trials of all the difpossessed a courage and a confidence ferent sizes of pipes, as one good obin his powers which never forsook servation of any particular diameter him; he engaged in the work a third and thickness of metal affords a rule time, and, by means of cylindrical for computing the comparative strength holes through the haunches. so re of pipes of any other dimensions whatduced their weight. that there was ever. The following are the results of

two of the above experiments. no longer any danger from it. The

The manner of making the trial is second bridge fell in 1751; the third,

this-the pipe to be tried is closed at which has stood ever since, was com one extremity, while the other commu. pleted in 1761. The present arch is nicates with a forcing pump, by means 140 feet in span, and 35 feet high, of which water is thrown into it and being the segment of a circle of 175 forced, until it presses the pipe on all feet in diaineter. In each haunch sides with a violent pressure, in the there are three cylindrical openings same manner as if the pipe were con

veying the water of a lofty spring, the running through from side to side;

effect of which is to press out the pipe the diameter of the lowest is nine

on all sides in proportion to the height feet; of the next, six feet ; and of of the fountai-head. But the pump the uppermost, three feet. The is also furnished with a valve or guage width of the bridge is about eleven which measures exactly the degree of feet. To strengthen it horizontally, pressure communicated to the pipe, so. 406

LIGHTING STEEPLE CLOCKS. that; in every experiment, we can com- the metal being much less ductile. putė the height of the reservoir which Such is the extreme pressure which would have caused a similar pressure these pipes will bear before bursting, by the water conveyed from it, and in but it would be unsafe in practice to this manner obtain a rule for adapt. subject them to more than one-third of ing the strength of each pipe to the this. Still, however, it appears that a pressure which its situation subjects it twu-inch pipe, with one-fifth of an inch to. When the water from the pump thickness of metal, will be sufficient first begins to press out the pipe, little for withstanding a pressure of 300 feet. or no alteration is observed on it for Many other examples might be given some time; as the operation of forcing of the applicatioil of these experiproceeds, however, and the pressure ments, did our limits permit.. We thereby becomes increased, the pipe shall just mention, however, an intergradually swells through its whole esting piece of antiquity, which was length, until at last a small protu- lately brought from Italy by Professor berance is observed rising in some weak Leslie; it is a Roman lead pipe, suppart, which coutinues increasing until posed to have been used in conveying the substance of the metal, becoming water to the haths of one of the Emgradually thinner and thinner, is at perors; it is not truly round, but of an last fairly rent asunder, when the pipe irregular oval or flattened shape, the bursts with a crash, and the water, metal appearing to have been turned issues with great violence. In the first over longitudinally, without any roller experiment the pipe was 14 inch bore, or njandrel, and then strongly soldered. aud the metal, which was remarkably It is, aš near as we recollect, about 24 soft and ductile, was one-fifth of an inches diameter one way, and 2 inches inch in thickness. This was forced, as the other, and the metal about threeabove described, until the pressure be- fourths of an inch thick. Now, it is came equivalent to that of a spring or evident from the above experimients, column of water 1000 feet high, which that the strength of this pipe is enoris equal to 30 atmospheres, or 420lbs. mously above what the occasion could on every square inch of the pipe. This require, and this shows the advantage it sustained without alteration, but with of having accurate experiments to a pressure equal to 1200 feet it began direct the construction of such works. to swell, and with 1400 feet, or 600lbs. on the inch, it burst. It appears surprising that the soft material of lead should sustain so enormous a pressure, LIGHTING STEEPLE CLOCKS. but this arises from its being equally

The face of a Steeple Clock, distributed through every part of the mass. There is no cross strain nor

illumined by gas, may be rendered unequal action in different parts of the equally readable by the inhabitants pipe, but a fair stretch throughout the in the night as in the, day; this has whole surface, which it is well-known now, for some years, been exemis by far the most favourable situation plified at the Tron Church, in the for strengih. On measuring the above City of Glasgow. A gas-lantern, pipe aster the experiment, it was found whose exterior (except on the side to have swelled out from 14 inch to 1), next the steenle where it is glazed) so that a part of the original pipe, which

tastefully represents the bird called had not been subjected to any pressure, could be inserted within the fractured

the phænir, is supported at several piece. The fracture of this piece pre

feet distant from and level with the sented a very striking appearance. The upper part of the clock-face, by two edges were no way ragged, but quite supports acting braceways to each smooth and sharp, like a knife, show other, and steadied, laterally, by two ing how the metal had been gradually chains proceeding from the corners distended and thioned out to nothing of the steeple : the main of these by the internal pressure, as if the pipe supports is the gas-pipe, which suphad consisted of soft clay or wax. In the second experiment, the pipe was

plies the lantern, and the other is two inches diameter and one-fifth of an

also a gas-pipe used for lighting the inch in thickness of metal : this sus

lantern. It effects this by means of tained a pressure of a column 800 feet numerous equidistant small holes, in height with hardly any swelling, but or narrow cross slits in its side, and with 1000 feet it burst. The fracture is called the flush-pipe. i At sun-set, here was not so fine as in the other, when the lantern is to be lighted, CALCULATION OF INTEREST.

407 the lamp - lighter, by means of day : one shilling :: 251, for 219 cocks fixed within his reach in the days : 15 shillings. street; turns the gas into both these I observed the trifling omission I pipes, and, after waiting a proper had made, in not stating the rale; time for the gas to ascend to the and in my letter, which I wrote, and lantern, he applies his flambeau to sent a few days after, containing the the jet of gas issuing from the low- 5 per cent. method (inserted p. 339, est of the holes in the flash-pipe, the vol. iv.), I requested that it might flame from which instantly commu- be noticed. nicates to the jet next above it, and

Yoir Correspondent has been so on, until in a few moments this chain of flame enters the lantern,

pleased in Number 105) to bring and lights the burner of the main

the fractional parts, named by me,

to a common denominator, and call it pipe, which being perceived by the

a solution of the question ! and in illumination on the clock-face, the the beginning of this letter, he makes flash-cock is then turned off, and no

an observation upon my remark of further attendance is needed until about sun-rise, when the other cock

reducing the answer from shillings is shut off, and this clock-lantern

and pence, to pounds, shillings, and

ern pence, by dividing by 20, there being extinguished, in its turn, with those

se a misprint of “or” pence for and in the adjacent street. The lantern

pence. is curiously glazed, convexly, in five panes; and a number of plane mir

As a preliminary step to iny solu. rors are, concavely, fixed behind the

tion of it, I will inform him, that it burner, to act as a reflector in throw

is easier to find the interest at 31. 13s. ing the light principally on the clock

per cent. than at any other rate.

Now, I believe it is well known, that face.

if any sum, the interest of which is

required at 5 per cent. for one day, CALCULATION OF INTEREST. be divided by 7300, the quotient will Sir,-In Number 105 of your va

be the answer; and at 4 per cent., luable Magazine, I observe a com

if by 925. And I find, upon the munication respecting the Calcula.

same principles, that interest at tion of Interest; and from it, it ap

31. 13s. per cent. is procured by dipears, that what was written by your

viding by 10,000. Correspondent, and published in

The difference between 5l. and Number 93, was to refute, and not

31. 13s. is 27 shillings, and between to support, the opinion, that if the 11. and 31. 135., 7 shillings. Let us product of pounds, multiplied by take the fractional parts of 73 shildays, be divided by 3651., the answer lings, which, when added, shall be would be given in shillings. The equal to 7 shillings. I shall take for idea, that it was a letter in refutation, instance (but, of course, many others never crossed my mind : because I may be chosen), 1-12th, 1-80th, and knew that the rule (though by no 1-17,500dth; and I find that, when means a short one) was quite correct; these parts are added to 31. 13s. the and, by consequence, I was misled. amount is 41. and a very sınall fracIn that part of his letter which is ex- tion. Thus, - 73 shillings. pressed thus:-365 days : 219 days

1-12th = 6.0833333 : : 251. : 151., I really imagined he 1-80th = .9125 was showing, that if 365 days were 1-17,500dth = .0011714, &c. used for a divisor, the quotient would be the ansiver in pounds, instead of . Shillings - 80.0000047 shillings; and which appeared to me. As 17,500 appears to be an 'awk- to be, what it really is, nonsense. ward sum to divide by, if it be quaInstead of his proving the fallacy of drupled, the sum will then he 70,000 the rule, as he has imagined, I will (which in dividing, &c. is the same, prove, and I hope to his satisfaction, as to trouble, as by 7); but care that his letter is fallacious; and that must be taken to quadruple its 100, very briefly, viz.-3651. for one quotient.

408 BURMESE CARRIAGE-GRAND BALLOON-VEGETABLE TALLOW.

Now it is evident that if any conceived, presenting one entire sum, x, shall be divided by these blaze of gold, silver, and precious fractions, and if the quotients added stones; of the latter 'the nuniber to x=y, the proportional ratio be- must amount to many thousands, tween x and y will be the saine as comprehending diamonds, rubies, between 73 and 80.

sapphires (white and blue), emeralds, The 5 per cent. method is founded amethysts, garnets, topaz, cats eyes, on the same principles as the fore- crystals, &c. The carving is of a going, and is, in my humble opinion, very superior description, the form the shortest and most correct that and construction of the vehicle excan be devised, viz.-Suppose the traordinary, and the general taste interest of 2191. for 25 days was displayed throughout the whole derequired :

sign is at once so grand and impos. 219 x 25 = 5475

ing, yet at the same time so chaste 1-3d - 1825

and refined, that we are told it may 1-30th - 1825

defy all rivalry even from European 1-300dth

1825 workmanship. The warlike power

and resources of this surprising 7500 | 75

people are at present exciting uni.1-10,000dth = 75

versal astonishment and attention :

this new object attests the fact that, 7500 1 00=155. in taste for design, and skill in exeIf any one choose to find the value cution of works of art, their talents of these fractions, he may satisfy have been equally hidden and unhimself of the correctness of the known to us. The carriage stands above. Thus, x +

between twenty and thirty feet in

x + 300 * height, and is drawn by elephants. 10000 of r + *, &c.= 100 shillings 369,863, &c. . , 27,000,000.

GRAND BALLOON. 27,000,000 "*. 369,863,&c.

Selim Ogal, of Smyrna, has just ; I remain, Sir,

finished one of the largest Air Bal. Your constant reader,

loons that has ever yet been made : G. U. A,

it is 140 feet in diameter, and the P.S.' I never give myself the trou. parachute 22 feet in circumference, ble to multiply by 20, 12, and 4, to and he intends shortly to make an reduce the decimals of a pound to ascension. Selim will be the first shillings, pence, and farthings; but, Turk who ever approached so near by inspection, I double the figure next the regions of their prophet in so the point for shilling's ; if the next frail a vessel. figure be 5, or upwards, take 5 from it, and add one to the shillings; there the second and third figures are far VEGETABLE TALLOW.' things, after deducting 1 for every

A Vegetable Tallow, extracted by 25 in them.

boiling from the fruit of the V'ateria

Indica tree, growing in Canara proBURMESE 'IMPERIAL STATE

• vince and others on the western coast

of the peninsula of India, which sells CARRIAGE

in Mangalore, at about 2 d. per lb., 7 The Burmese Imperial State Care has lately been brought to London, riage, which has been captured in in a very hard and tough cake, expethe present sanguinary Indian war, rimented upon by Dr. B. Babington. has reached this country, and is now It is easily made into mould candles,

preparing for public exhibition. , It' which afford as bright a light as the ! is said to be, without exception, one best animal tallow, and without any

of the most singular and splendid unpleasant sinell, even when blown works of art that can possibly be out.

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SIR,--In page 64, vol. 111. of your windows, valves of chimneys, or Magazine, à Subscriber wishes to Alues and steam-cocks, Mr. Kewley, have a description of an invention the inventor, uses a metal cylinder, for regulating the Heat of Hot F, from 7 to 14 inches in diameter,and houses; I shall be happy to give him from 18 inches to 2 feet in length, all the information in my power. with an accurately fitted piston, G.

AA are a glass tube, from two to This cylinder is placed in any conthree feet in length, hermetically venient situation, and a barres filled scaled at one end, and united at the with water is placed on an elevated other to a capillary tube, BB, with situation, with a pipe from it, H, to an intervening and also a terminating a point directly under the thermoball, C and D. The largest tube, meter, and not higher than the botand half the intervening ball, are filled tom of the cylinder; here it joins with spirits of wine ; and the smaller, the pipes I and K; 1, a waste pipe, and half of both the balls, with mer- and K, a pipe entering the cylinder cury. The tube is fixed by its cen- below the piston. At the point, L, tre in a brass frame, E, and nicely is a tripartite cock, the handle of balanced. It is evident, then, that which, M, turns only to the extent every change in the temperature of of one-fifth of a circle ; when turned the atinosphere will produce a change to the right, it opens a communicain the position of the centre of gra- tion between H and K, when the vity of the tubes. One degree of pressure of the water' raises the pisheat, by expanding the spirit, will ton, and opens the sashes, &c. by the

press on the mercury at C, and drive chain, N; when the cock is turned s part of it over to D, which end will, to the left, this communication is

in consequence, descend like the stopped, and one opened between I beam-of a pair of scales. ini and K, by which the water escaping

In order to apply it to opening the piston descends, and the sashes,

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