are understood to have resolved on, since they have made such considerable alterations at the Bow-street end of the line. The details, as they are given in this plan, are not of a very satisfactory character. As it is, the street from the bridge to Long Acre is remarkably crooked.

"A new street from Finsbury-square to the Commercial-road."

The great improvement wanted, with regard to the Commercial-road, is to continue it on to Aldgate High-street. The present plan has nothing whatever to recommend it.

"A new street from Holborn to the Strand, and taking down the houses on the north side of the Strand between the churches of St. Clement Danes and St. Mary-le-Strand."

The widening of the Strand in the part described might be desirable, but there is such a thing as making a street too wide, and in this case that fault would be particularly striking from the necessity, (unless St. Mary's Church be taken down, which will scarcely be proposed) of communicating after all by only a narrow isthmus with the other wide part of the Strand in front of Somerset House. With regard to the new street to Holborn, the plan here brought forward has more merit than most of its companions. It is to take the western side of Lincoln's-Innfields for part of the line, and at either end force a way into the main street nearest it. But the great advantage of selecting this side of Lincoln's-Inn-fields, instead of the eastern, seems to have escaped the projector. If the new way thus made into Holborn were continued across it for the length of 100 yards, it would enter King-street, and a direct communication, as straight as any street in London, would thus be effected between the Strand at Somerset House and the Hampsteadroad. This new road is more eligible in every point than the proposed more western one by Gower-street.

"The improvement of the thoroughfare from St. Katharine Docks to Eastcheap."

This consists in the widening of the Tower end of Tower-street, and the pulling down of some projecting houses on Tower-hill. It would, no doubt, be a useful improvement.

"The removal of Middle-row, Holborn." A scheme which hardly needed the assistance of a lithographic plan to make

it intelligible. A street, as was before remarked, may be too wide. Holborn in front of Furnival's Inn is assuredly in that predicament; and if Middle-row be removed, some other object—a statue or public monument of some kind-will certainly be required on its site to mark the distinction between a street and a common.

"County of Surrey.-A new street from St. George's, Southwark, to Blackfriars' Bridge."

This new road is to be a continuation of the well-known line of Stamfordstreet, which, suddenly starting from the river-side, is, for some reason or reasons unknown, to make a desperate rush at St. George's Church in the Borough. A union with Tooley-street would be more in consonance with its previous habits.

"A continuation of the proposed new street from St. George's Church, Southwark, to Blackfriars' Bridge, Waterloo Bridge, and Westminster Bridge, and to the proposed Foot Bridge at Lambeth."

This recommendation must have slipt in by some mistake. The continuation alluded to is, as shown by the plan already in existence (with the exception of a branch to the Foot Bridge), under the name of Stamford-street.

These, then, are the improvements proposed which the Committee calculate may, with the purchase of the interest of the proprietors of Waterloo and Southwark Bridges, be effected for a sum not exceeding 1,2000,00%, but which they, duly considering the uncertain nature of estimates, require 300,000l. more to begin with.

The reader who has followed us thus far will, we think, be unable to repress a feeling of disappointment at the results of the Committee on Metropolitan Improvements." A commonly attentive glance at a map of London might, one would think, have suggested proposals far superior to any they have recom mended. It is said that the central avenues of the City are choked up with too abundant traffic. Does not the map explain this? To the westward there are two great thoroughfares towards the centre-the Strand and Holborn; to the eastward there are also two-the Mile End and Commercial Roads; but in the centre itself these great roadways con

verge into one, and Cheapside is made to bear all the burden of all the commerce that traverses these grand avenues from east to west. The remedy is obvious; at least, one other line of way to the north of Cheapside is called for. The map will likewise show the great deficiency of lines of road from north to south, there not being one, with the exception of Bishopsgate-street and its continuations, that fairly traverses the metropolis. For one of these desiderated thoroughfares, an excellent line is pointed out in this evidence (by Samuel Mills, Esq., a Commissioner of Sewers), in a continuation of Old-street to Theobald's-road, and so on to Oxford-street; another was suggested

years ago by Mr. Nash in his proposed improvements of St. Martin's-lane, so as to communicate at one end with Charlotte-street, at the other with Whitehall. Had the Committee kept a few great ohjects like these in view, and carefully considered plans to effect them, not only consulting the utility which ought to form their chief feature, but the beauty which, under able management, they might be made to present, they would have done honour to themselves-rendered an essential service to the City and the citizens-and not have thrown away the public money by having plans en graved for new streets from Newgatestreet to the Post-office.

Sir,-In London, where fires are of very frequent occurrence, the experience of the firemen enables them to attain great skilfulness in their method of dealing with that destructive element. From constant practice they are enabled to approach so close to the burning materials, as to deliver their engine-streams pointblank upon the very heart of the fire, even in the midst of such quantities of heat and smoke, as would render it impossible for less practised persons to keep their ground for an instant.

It not unfrequently happens, however, that persons have the care of engines and are called upon to extinguish fires, whose opportunities of acquiring the needful experience in these matters is exceedingly limited, and they therefore seldom make the best use of the means at their command. A striking instance of this sort occurred about four months back at the

Bank of England. There are no less than seven excellent fire-engines kept within the walls of the Bank, which are inspect-ed by the maker every month, and there is in every department a good supply of leather fire-buckets. In each of the yards capacious tanks are judiciously placed and kept constantly filled with water. There is a nightly guard of thirty-twosoldiers sent from the Tower, besides which, a number of the porters, of the principal clerks and other officers of the establishment, constantly reside in the building. Notwithstanding all these admirable arrangements, and the presence of this considerable force, upon the occasion of the recent fire, they battled with it for nearly an hour, and finding themselves gaining no ground, they sent for the assistance of the London fire-estab.. lishment. When the firemen arrived they found the men belonging to the Bank

working their engine from the outside of the building, through an open window of the room at the further end of which the fire was at the time raging; much labour and a quantity of water was thus use. lessly expended, and falling upon some valuable machinery in the room did much injury.

The moment the firemen ascertained the nature of the danger, they seized the branch of the engine, dashed through the window into the room, and advancing close to the burning timbers, poured the full stream of water thereon, and soon extinguished, the fire. Instances of this kind are of constant occurrence, and it is rather surprising that some contrivance has not been adopted that would obviate some of the dangers and difficulties of the case. It appears to me, that there is an invention of long standing, though fallen into complete disuse, and at the present time almost entirely unknown, that is calculated to be eminently useful upon occasions such as I have referred to; it is the perforated boss or nose of Mr. Joseph Bramah, included in his patent "for several improvements and additions to fire-engines,” dated April 18th, 1793. It consists of a copper hemisphere, flat on the under side, and perforated on the upper surface, rather more than half way over; it screws on to the top of the branch-pipe the same as any other kind of nozzle, and throws the water in a great number of minute streams in every direction, as shown in the accompanying sketch. Mr. Bramah, in his specification says, "this boss or nozzle is meant to be used in such cases as will admit of a man approaching to the part where the fire is first begun, or at any other period when deemed useful.”

Were an engine furnished with one of these perforated nose-pipes, although the person in charge of it, from want of practice, was unable to remain in the apartment where the fire was raging furiously, yet he might run in, drop the branch thus equip ped, and then retire; the effect of working the engine would be to deluge all paris of the room, and most effectually in an incredibly short space of time, to extinguish the flames.

Even the bravest and most expert fireman might often use this apparatus with advantage, for it frequently happens that a fire has attained such a head in a par

ticular apartment, as to defy any living creature to remain many seconds therein. In such cases the fireman might boldly enter, and having placed his branch, withdraw; in a few minutes he would find the fire almost, if not wholly, extinguished the atmosphere of the room cooled down to a bearable temperature, and the greater portion of the smoke condensed or dissipated-and all this done with the smallest quantity of water.

: The firemen occasionally spread the water by putting their thumb on the orifice of the branch-pipe, but it is done very imperfectly in this manner, and can only be attempted upon occasions when the firemen can remain in the room. By means of a long pole, the branch, equipped with the perforated boss, may often be pushed along into places where it is utterly impossible for a man to enter, and in a very short space of time would make a position tenable, from which the fireman might follow up the advantage thus gained. I am quite of opinion that the general employment of Bramah's nozzles within buildings, would greatly expedite the suppression of fires, and very materially reduce the amount of damage done by water.

I am, Sir,
Your obedient servant,
W. BADDELEY.

London, Feb. 23, 1837.

MR. MACKINTOSH'S ELECTRICAL

THEORY.

Sir,-Mr. Mackintosh is not satisfied with the method I pointed out to him (No. 705) for obtaining information respecting the first question he put to me. (No. 693), namely, to give him a demonstration of what produced the first impulse ?" I referred him to his own Pastor for a solution of his own proposition. Indeed, it struck me at the time, that the question was not altogether a proper one for the Mechanics' Magazine; and farther, as Mr. Mackintosh has taken good care not to answer some questions I put to him on his Electrical Theory of the Universe, I conceived I had no right to answer his. But in consequence of some remarks he has thought proper to make in his last letter (No. 708), I beg leave to offer a few remarks on the first question, and also upon the second, as he

conceives them to be of such great im-. portance as to involve the truth or falsehood of the whole system: but whether he means his own mighty system, or that of poor Newton's, I cannot tell.

Question. What produced the first impulse?

In the way this question is put, Mr. Mackintosh assumes that matter must have existed before motion, or there must have been a time when all the matter in the universe was in a state of absolute rest; in that case, I should have no hesitation in saying (and his Parson would have told him the same, and saved me the trouble) since no change can take place in nature without a cause, the first impulse must have been produced through the agency of a supreme Being.

Had Mr. Mackintosh pondered sufficiently upon the above question, he never would have philosophised in the way he has done. Perhaps he meant to have said," Had matter and motion ever a beginning? If not, can their existence be or not be dated from the same period of time?" &c. Here I might have had something to grapple with, and not a mere shadow; but I have no right to put words in his mouth.

Mr. Mackintosh then proposes this second important question-" From what force is the motion of the heavenly bodies derived ?" That force which could impart motion in the first instance, can sustain that motion, and is required to do so, as otherwise the motion would be quickly annihilated by the action of gravity. Here, again, I am sorry to inform Mr. Mackintosh, that this second question has no great pretensions to absolute wisdom. I am afraid his perpetual motion wheel has so completely absorbed all his other faculties, that he has not only forgotten his knowledge of the Newtonian system, but that he is a little rusted in his own system. Well, I must endeavour to rouse him up a little.

The answer to the first part of Mr. Mackintosh's question is- Gravitation ; and with regard to the second part, Mr. Mackintosh surely has not forgotten that the heavenly bodies, belonging to the solar system, revolve round the centre of gravity of the said system. But let us simply consider the case of our own planet. When the earth is in that part of her orbit nearest to the sun, the gravitating power, or the attraction which the sun

has upon the earth, is a maximum; the consequence of which is, that the velocity (and consequently the momentum) at the said point is also a maximum. But when the earth is in that point of her orbit most remote from the sun, the ve locity and momentum become a mini. mum, that is, as the gravitating force of the sun acts more and more upon the earth, the centrifugal force of the earth is increased, and conversely; so that, far far from the motion of the heavenly bo dies being annihilated by gravitation, it is, in fact, gravity that regulates and preserves all their motions. Suppose the gravitating force of the sun were to be destroyed, then the angular motion of the planets would immediately cease, and what would be the result? The answer is easily given the whole race of inhabitants belonging to the solar system would be (not roasted, but) frozen to death. And all this is demonstrated by Newton, in his "Principles of Natural Philosophy," and has been amply confirmed by observations. I again repeat, that it was study and observations that led Newton to a knowledge of gravitation.

In conclusion, I beg to state that there is no such thing in nature as absolute rest; place a body as far as possible from any other body or bodies, still it will be within the influence of their gravitating powers, and without any impulse it will immediately commence mo

tion.

SOLUTION OF A TOWN-TEACHER'S MATHEMATICAL QUESTION. BY 0. N. Question." The late Dr. Hamilton, of Aberdeen, in his excellent System of Arithmetic,' asserts, that the interest of 1,000, at the rate of 5 per cent. per annum, on the principles of compound interest, for half a year, is only 247. 13s. 93d. How can this be, when the simple interest for the same sum, at the same rate and time, is 251.? Perhaps some of your algebraical correspondents will be so kind as to explain this (to me) seeming paradox."

Solution. The Town-Teacher remarks, that the interest of 1,000l., at 5 per cent. per annum, is 257. for half a year. I

deny this position, for the following reason:-Suppose A owes B 1,000l., and A agrees to pay B 5 per cent. per annum, that is, 50%. at the end of each year? Then, I say, B has no right to demand 257. from A at the end of six months; for on the supposition that A was to pay B 251. at the end of six months, he would løse the interest of 251. for half a year, therefore A ought only to pay B (if he chooses to accommodate B with half a year's interest six months before it is due) such a sum as improved at 5 per cent. per annum would amount to 257.-which sum, by rule of discount, will only be 941. 7s. 94d. So much for the simple interest case.

2d. In the case of compound interest, assume 1000P, R amount of 17. for 1 year, amount of 17. for half a year; then, by the principles of compound interest,

1:x:P:P amount of £P for half a year, and 1:x:: Px: Pæ2= amount of £P for one year; then, by the question,

P2 PR, or x=√R Leti interest due at the end of half a year, then

i=Px-P=P (x−1) = P(√√/R−1)

P. S.-I could not help admiring the dexterous way your correspondent, R. Evans, or rather his friend, the Actuary (Mr. Williams), extricated himself from the false solution he gave of the distance travelled by Mr. Green's balloon in his great Continental trip (see Nos. 695 and 704). His last corrected formula is tolerably exact for certain latitudes and longitudes; but many examples might be given where the true distance does not exceed 359 English miles-but if calcu lated by the principles of taking the middle latitude, would produce errors amounting to between 50 and 60 per cent.

MEDAL ENGRAVING BY MACHINERY THE ENGLISH AND FRENCH PROCESSES.

Sir, If it were not unhappily the case that the "fantastic tricks played by Committees of the House of Commons are but too often of an entirely inexplicable character, the very highest degree of surprise might naturally be excited at the method adopted by the British Museum Committee to dispose of the "Medal Engraving by Machinery" question.

or rather to avoid disposing of it at all. The evidence adduced is of such, a character, as to establish the superiority of the British process over that of Collas beyond the possibility of a doubt; while the other disadvantages attending the project set forth in the petition referred to the consideration of the Com. mittee, are so numerous, and so obvious, that they scarcely require more than to be barely stated to insure (at any rate when taken in connexion with the former fact) its instant condemnation. And yet, after all, the Committee contented themselves with reporting the Evidence alone, without giving any opinion on the matter! If this were the course usually pursued when the case was so plain that it might seem a work of supererogation for alparliamentary jury to deliver a verdict in full form upon it, every thing would be accounted for; but I believe it is not so that, when a Committee decline giving an opinion, it is to be inferred either that they have not sufficient grounds for coming to a decision, or that the members are so equally divided in sentiment, that any thing like unanimity is not to be looked for. Yet it is hard to believe that the Committee could be in any such predicament on the occasion in question. The balance of testimony is so enormously in favour of Mr. Bate's process, that nothing less could have been reasonably expected than that the Report should have strongly recommended him to the patronage of Parliament, (in case Parliament should think it fitting or necessary to extend its patronage to any scheme for engraving the medals in the Museum,) and advised his French rivals to return to the place from whence they came. It may be an uncharitable notion, but certainly, all things considered, it is not altogether an outrageously absurd one, to suspect that, had Mr. Vincent Nolte and his backers gone on to the end of the in