with its size; that is very inconsiderable, when you observe that the breast of the engine is so large; but I have not found it necessary to provide against sudden gusts; for the extreme velocity with which the smoke or sparks leave the chimney, as well as the velocity of the machine itself, will, without regard to whatever wind may be stirring, cause the sparks to go into the shield per force.

John Urpeth Rastrick, Esq., C.E., examined.

The principal danger to be apprehended from fire is from the coke being blown out of the top of the engine chimney, but that has been guarded against by the application of caps to it; and all the observations I have made in all the opportunities I have had, I have never seen sparks come out sufficiently large to produce fire from the top of the chimney. In fact, I have frequently rode in the Bolton waggons, which run between the Liverpool and Manchester Railway and Bolton, on the outside, and I have not otherwise been annoyed than by small particles of dust which came through the cap at the top of the chimney in one's face. Coke is a material that requires a very great degree of heat to consume it; in fact, it will not answer the purpose without a very strong blast. On board of steam-boats it would be very desirable to get quit of the smoke if possible; but sufficient draught cannot be got to produce that intensity of heat necessary for generating' steam without some other means to render the blast stronger than that of a mere chimney. I have been connected with the ironworks all my lifetime; and perhaps I might call the attention of noble lords to a circumstance of one particular operation in the manufacture of iron, which is the second process; that is done by putting a certain quantity of pig iron into a furnace called a finery; then it is blown upon with a very strong blast, and coke is the material that is used. There' the sparks come out at the top of the chimney to a most extraordinary extent; in the night it looks like a large firework. Now, I have always observed that these sparks, though they appear to be quite ignited when they come out in that great strength of the blast, the moment they come out they begin to die away immediately; in fact, in a great many buildings connected with ironworks, where there has been a long time of dry weather, these small particles of coke, which rise up into the atmosphere in an ignited state, fall, and fill up the spouts by the sides of the roof, and lie on the buildings till there is a shower of rain to wash it away. From that circumstance I conclude that the small particles of coke that are enabled to fly up into the air to any extent must be very soon completely cooled down, especially with loco,

motive engines, where a guard is put over the top of the chimney, more particularly if coke is ignited. At the time they come out they must be so remarkably small that before they have gone a few yards, they completely lose that degree of heat necessary to give them an appearance of sparks. (To be continued.)

NOTES AND NOTICES.

Glass Cloth.-Signor Olivi, of Venice, has recoutly succeeded in bringing to perfection a manufacture which may prove of great value, and may be applied to many purposes of usefulness and luxury. It is the art of weaving a tissue from threads made of glass. The process of which the Signor is the inventor differs from all the attempts of the same kind which have been previously made in other countries, as it is made to take every degree of shade, from the most perfect transpareney to the deepest opaque. The thread is also rendered so perfectly flexible as to allow ttself to be tied, or the tissue, when manufactured, to be folded like silk. Another great advantage attending it is, that it resists the action of fire. The specimens which have been exhibited have called forih the highest admiration, and the brilliancy of colour given to them is altogether surprising. Although the Institution of Arts at Venice has awarded medals to Signor Olivt for his invention, it is said that he does not meet with the encouragement from the Austrian Government which he expected its singularity and beauty would ensure.

Effect of a Comet's impinging on the Earth.-If a comet were to impinge on the earth, so as to destroy its centrifugal force, it would fall to sun in 64% days. What the earth's primitive velocity may have been it is impossible to say; therefore a comet may have given it a shock without changing the axis of rotation, but only destroying part of its tangential velocity, so as to diminish the size of the orbit, a thing by no means impossible, though highly improbable; at all events there is no proof

that such has been the case.-Mrs. Somerville.

The Supplement to Vol. XXV., containing Ti tle, Table of Contents, Index, and Plate of Specimens of English Medallic Engraving by Mr. Bate, was published on the 1st of December, price 6d.

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DESCRIPTION OF CHRIST CHURCH SPIRE, DONCASTER, AS STRUCK BY LIGHTNING, NOV. 3, 1836.

Sir, In several Numbers of your valuable Magazine, I have seen communications relating to electrical phenomena, which lead me to think the following account of the destruction of the spire of Christ Church, at Doncaster, by lightning, may not be unacceptable to you; nor altogether uninteresting in a scientific point of view, as it demonstrates more fully than any accident of the kind I have ever heard of, the efficacy and indispensableness of conducting-rods.

On Thursday, Nov. 3, a thunder-storm passed over the town of Doncaster, which in its commencement was not of such an awful character as to lead to the apprehension of any serious result. After a few peals of thunder, an interval of death-like stillness occurred when it appeared as if Nature was concentrating her powers for some mighty effort. I was standing at the time in the doorway of a building situated in a south-east direction from the church, about threequarters of a mile distant, and was looking towards the town, when a tremendous flash of vivid white lightning, that seemed to 66 set all ether in a blaze," was followed, or rather accompanied, by a long, slightly zigzag streak of a dingy-reddish colour, which originated apparently in a dense black cloud at some distance northeast from the church, and took a horizontal direction until near the spire, when it gradually curved downwards, and finally struck its summit. A bright corruscation appeared for an instant on the apex of the spire; at the same time a dense cloud of smoke arose round the fabric, and I saw the displaced fragments falling to the ground. This beautiful little church was erected in 1827-8. Its site is somewhat elevated, and the height of the spire was about 150 feet. When the building was finished, a mass of glass of a somewhat conical shape was placed upon its summit, which, being a nonconductor, it was supposed might prevent accidents from lightning, to which its great height, and pointed form, obviously rendered it extremely liable.

The accompanying ink-drawing is from a beautiful oil-painting now executing by Mr. Hepworth, of this town, and is a faithful representation of the appearance of the spire on the morning succeeding

the accident; the dotted lines show the original elevation.

From the present state of the spire, the following conclusions may be drawn:The electric fluid has first struck the apex of the spire, about 12 feet of which it has shivered and thrown down; several lines of fracture appear in the remaining portion of the spire. But the main body of the fluid seems to have taken a spiral direction downwards from a to the lancetwindow b, where the stone-work is dreadfully shattered. From this point it has turned again along a lead-gutter at d, and down a lead pipe inside one of the traceried windows below, which discharges the water between the slate composing the window; at the termination of this pipe it has again entered the stonework between the windows e, (where the tower is here fractured for above a yard) until opposite the bell, where it is lost; but most probably from this point it flew to the bell, and from thence down a copper wire to the clock-work in the chamber below; of this there is one very confirmatory circumstance, viz. the beam through which the wire passes is very much rent. From the clock it has made an easy transit to the gas-pipe which conveyed gas for supplying the illuminated dials, and has followed the course of this pipe down to the earth. The plate-glass of the illuminated dials has been shivered to atoms; and a very few fragments remain in the iron framework, which is not at all injured. The gas-pipe along which the fluid has passed enters the clock-chamber at a circular window corresponding with the three dials, a few feet above the roof of the body of the church. A few inches below this window about eight inches of the pipe was melted, and the gas ignited; and the pipe was again melted in the interior at perhaps two yards from thisevidently proving that this was the path pursued by the electric fluid in its course downwards to the earth. It is remarkable, that while the gas-pipe, which is of copper, and about half an inch in diameter, has been melted, the copper wire connecting the bell-hammer with the clock-work, which is of the size denominated by the manufacturers No. 16, remained entire and uninjured.

This occurrence is extremely interesting, inasmuch as it proves beyond a doub the total inefficacy of cones of glass, or

other non-conducting substances, placed on the summits of lofty buildings; and also as it demonstrates, in a most convincing manner, the importance of conducting-rods. There is no fracture any where in the walls below the pier at the side of the traceried window e; from this point the electric fluid has found a series of conducting bodies capable of carrying it off, and to this the preservation of the lower part of the structure is most probably owing. I am, Sir, yours, &c.

I. R. H.

HOUSE-BURNING SYSTEM.

Sir,-Will Mr. Baddeley, who may truly be termed the "Amateur Fireman," tell me

1st. Whether a more effective instrument than the fire-engine now in use is desired by the Fire-Insurance Companies? If not, as the lawyers have it, why not?

2d. Why Mr. Braithwaite's steam fireengine (which all admit to be an effective instrument) has not been adopted?

3d. Whether a return could be had of the number of fires for a given time (twelve months) distinguishing between insured and uninsured; stating, also, whether the fires began in the one class of property or the other; and what the relative loss of property in each case, compared to the other, is?

1 bethink me a negative will be the answer to my first-fear of " Othello's occupation being gone," to my second-and an exposure that would lead to public reprobation, to my third query. Mr. Baddeley is an extremely intelligent man, and clever writer; let him show himself honest and fearless also, by "nothing extenuating" in his reply, for he appears to know more of this matter than we of the commonalty do.

Your obedient servant,
FIRE-FURY.

STRICTURES ON THE ELECTRICIANS.

Sir, I trouble you with some observations on electricity, and also on a species of mania which has of late years possessed the greater number of the sta dents in the science; and in particular branches of it, so bewildered their under standings, that they seem to have quite

forgotten the advice of their great guides, Bacon and Newton, by following which so many great discoveries in this science have been made.

I suppose it is the greatness of these discoveries, added to the love of novelty, that has produced this unfortunate aberration of intellect, which I beg leave to name electrophobia. Its baneful effects have chiefly appeared in an almost total abandonment of the inquiry into the fundamental principles of this noblest of physical sciences, which it so much concerns the astronomer, the chemist, the geologist, and so many ers and ists besides, to be well instructed in; and without a more searching inquiry into which, I am inclined to think the subdivisions of the science, magnetism, galvanism, &c., will, in some of their more abstruse principles, remain long in their present obscurity.

Franklin framed a beautiful theory, considering the infancy of the science in his time; and in his principles (and assumptions, too) the English philosophers, who at first neglected him, have become quite fast set-so much so, that ever since they have scarcely dared to question them.

Though neither he nor they could untie the knot of negative recession, which he assumed to be repulsion, yet, with a truly Roman, undoubting, steadfastness they seem resolved, at all hazards, to persevere in that assumption Witness, amongst other instances, Dr Ritchie's and Professor Stevelly's observations in answer to Professor Hare, at Bristol last August.*

Mr. Du Fay (according to the French philosophers), Mr Eeles (according to the Irish), and Mr. Symmer (according to the English)-forgetting the simplicity of nature and Newton's consequent rule, not to admit more causes than a necessary to explain natural phenomena— created another electric fluid to untie the Gordian knot of negative recession, as Franklin had before created a new power. I am compelled to believe, as far as

* I should feel extremely obliged to any one who would refer me to any account of the experiments then mentioned by Dr. Ritchie, where the goldleaf electroscope diverged in vacuo. The Doctor's assertion seems directly in the teeth or similar experiments by Sir Humphrey Davy with the corkball electroscope, and which I m with somewhere in the Philosophical Transactions. In these on the gradual abstraction of an the electrified balls gradually diverged, and the converse on its gradual re-admission.

my present information of facts goes, that there is no such thing as repulsion in nature. Attraction alone (pursuing Newton's rule) seems to me sufficient to explain every thing that it concerns in or other sciences, far more

rehan with the assistance of

that hypothetical and unsocial force repulsion. I formed this opinion three or four years ago, as soon as I had acquired any thing like a comprehensive view of the subject; and I was still more confirmed in it by the fact of two friends, to whom I named it, having also come to the same conclusion.

Pursuing the consideration of the subject, additional arguments suggested themselves till I acquired a belief in homogeneous attraction of electricity also.

Magnetism and electro-magnetism furnish the greatest obstacle to the rejection of repulsion altogether; but let us go back from those more complicated subsciences in which the discovery of Oersted, and others, has given our philoso phers the above-mentioned phobia, and inquire whether we are right in sustaining Franklin's assumptions from the fewer facts then known, as well as his incontes'ible principles, if any such there be. Let us go back, I say, to the foundation of the science, to machine electricity, when our first inquiry will be whether electricity be in reality matter and a fluid. It is still much questioned, but I could perhaps demonstrate it from past experi ments of others (which have not been closely enough examined), without resorting to nearly 200 experiments I have noted down for trial on the particular point, and one or two of which I have made.

Under this first head, as necessarily connected with the experiments I shall propose to prove it, I intend to introduce some new considerations on the best mode of forming conductors, so as to produce the maximum effects depending on the tranference of electricity.

Under the same head, also, will perhaps not inappropriately come the consideration of a method of measuring the velocity of clectricity, which, I do not

*

Since I first wrote the text, I have found in a little anunal lent to me (called The Arcana of Science and Art), a short account of Professor Wheatstone's method by means of a revolving inirror. My method is intended to register the velocity, and the time also occupied in passing a particular point.

doubt, may be ascertained as accurately as the motion of any other fluid, as I think I perceive sources of fallacy in the principal attempts already made. At the same time will be considered a method of ascertaining the time taken by the fluid in passing a particular point in the circuit.

These latter topics will naturally lead to observations on the experiments of Dr. Watson and the Royal Society, tending to show a fallacy in their assumption, of the electricity in those experiments being in motion in a complete circuit from the inside to the outside of the phial, and to the suggestion of some experiments that must, I conceive, settle the question.

If electricity prove to be fluid matter,† the next thing will be to show it has an attraction for other bodies, a thing I suppose not doubted by any one who thinks it is material. After which, I think it will not be inappropriate to discuss a question that I have never seen glanced at even by those who deny repulsion. Has electricity homogeneous attraction? I think it has-I feel scarcely a shade of doubt of it. I think it might be satisfactorily established from recorded experiments, independently of 30 or 40 experiments that I have noted for trial on the point, and which I fancy must settle the question pro or con. If settled pro, aivay goes all the old rubbish about electrical repulsion; unless, indeed, its supporters will say that the particles of electricity have the paradoxical property of both attracting and repelling each other. As well might they say the parts of a sponge repel each other when they make way for the water their attraction forcibly brings into its pores.

If the experiments on homogeneous attraction of electricity should prove its non-existence, the question of repulsion still remains open, and I have numerous experiments noted for trial to negative

I have long thought it might be the undulations of this fluid, extending to the sun and pervading all things on earth, that caused light; but have little considered it. At present nothing has occurred to me that militates against that supposition. I have been the last few months doing what I have contemplated a year or two past, constructing a balloon to carry up a cord with brass thread in it, to ascertain the relative quantities and intensities of electricity at differeut heights; but this plan I have not yet had time to complete. If electricity do extend and increase in intensity to the greatest attainable height, why may it not extend to the Jun?