bucket, and the other at the bottom of the barrel; the latter of which is so ingeniously arranged, as to be accessible and removable at pleasure, by merely unscrewing the union joint which connects the pump with its feed-pipe. The action of this pump is remarkably pleasant and easy, and its compact form recommends it as peculiarly adapted for situations where saving of room is an object; while, by the addition of an airvessel, it is at once converted into an efficient fire pump.

Although shown as applied to a lifting pump, this motion is equally applicable to a forcing pump, by changing the lever from one of the first to one of the second order.

ON THE PROTECTION OF MANUFACTORIES, ETC. FROM FIRE.

Sir, I have perused with much gratification the Practical Suggestions for the Protection or Manufactories from Fire," at page 2 of your 960th number; if the same quantity of forethought and prudence exhibited by "A Manufacturer" were generally found to prevail, the entire character of London fires would be completely changed. His narrative clearly shows at how trifling expense an efficient safeguard against fire can be provided.

If the subject of fire were one more generally attended to, the present mass of ignorance respecting the best means of suppressing it, would soon give way to better notions. That water will extinguish fire, is admitted on all hands: but the necessity for providing water, or taking any measures towards its efficient application, seems to be a matter altogether beyond ordinary apprehension. Even the power of the one element to subdue the other, is very imfectly understood, and hence results incalculable mischief. Few persons have any idea of the small quantity of water that will suffice to stop the early progress of a fire. Let but the burning surface be covered with a film of water, no matter how thin, and combustion is at an end. By mechanical aids a single teacup-full of water may be made to cover upwards of six square feet, and therefore, to extinguish that quantity of burning material.

Mr. Loudon, in his Suburban Gar

dener, directs that "on the ground floor of a house, immediately within the outer door, one of Read's syringes (or some other equally efficacious) ought to be kept, and every male person in the house instructed how to use it. Precautions of this kind are useful as leading to habits of carefulness and forethought, which, after all, are the surest means of preventing accidents by fire." Many a fire that might on its first discovery have been extinguished by a single bucket of water, has been permitted to rage unchecked until more powerful means could be brought to bear, by which time it has become altogether beyond suppression. The recent destruction by fire of the Derby Town Hall, is a remarkable case in point.

Even firemen, from not having a clear perception of the subject, are continually doing more damage with water than is done by the fire itself, by using the former in quantities greatly beyond the requirements of the case. There are few rooms, the surface of which could not be covered by a few pints of water, and the effect of bringing an ordinary fire-engine to bear upon an apartment in the manner usually done, is to drown it and all beneath. An ordinary fire-engine throws about one gallon of water at every stroke, and makes from 60 to 70 strokes per minute, so that in the space of a very few minutes, several hundred gallons of water are needlessly thrown into the room, drenching the lower part of the building.

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We continually find that persons having large properties at stake, take no steps towards the protection of their premises, under the false impression, that this can only be accomplished by some powerful expedients provided at a great expense. The fact is, that, merely pail of water under each workman's bench," would in many cases have sufficed, and would in several instances, within my own knowledge, have been the means of saving thousands of pounds' worth of property. I have a model fireengine of a very small size, which has on more than one occasion stopped the spread of fire, and saved property to a large

amount.

A bucket, a syringe, or a pump of the sinallest calibre, with capacity on the part of some one to make a prompt application of them, would in nine cases

out of ten arrest the progress of incipient conflagrations, which, for want of such timely opposition soon extend far beyond the powers of human skill.

The late Mr. Russell took great pains to introduce the fire-pump, but he was neither the originator nor improver of it. The lifting force pump fitted with an airvessel had been used as a fire-engine nearly a century before Mr. Russell's time, and is an article that has been regularly supplied by all engine and pump makers for many years.

A mistake too often prevails in fixing these pumps; they should invariably be placed, with the handle at least, outside the premises, and not within. Astley's theatre was provided with a pump of this kind, which, if it had been placed externally, would most likely have saved it; but being placed within the building, no person had courage enough to stand amid the smoke to work it, and the fireman was forced to drop the branch and make a hasty retreat.

Where there is a well, or wherever a large tank can be sunk and connected with some certain supply of water, a firepump is invaluable. It should be enclosed within a strong casing to protect it from frost, from dust, and from wanton injury; one length of hose should always be attached to the nosel of the pump (unless the water is used for ordinary purposes,) and two or three lengths more of hose should be coiled on a hose-reel within the casing of the pump. Above all, the branch pipe should be provided with a spreader, in order to produce the film of water, of which I have before spoken, and by which so large a surface may be covered with the smallest quantity of water.

I propose at some convenient opportunity, to make a further practical application of some of the points herein alluded to, which time will not permit me to do at present, and remain,

Very respectfully, yours,

WM. BADDELEY.

29, Alfred-street, Islington, January 7, 1841.

PREVENTION OF FIRES.

Sir,-The observations of your indefatigable and sagacious correspondent, Mr. Baddeley, on the efficiency, or inefficiency of fire-engines, the supply of water, &c. &c., are very cogent, as is

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every thing he writes. But I would wish to draw his very valuable attention to the old axiom, that "prevention is far better than cure." Now, the "prevention" of houses taking fire was mainly and very effectually invented fifty years (?) ago, by the very intelligent Mr. Hartley, who, in conjunction with Sir Joseph Banks, constructed a house on Wimbledon-common, which still exists in perfect repair. The propinquity of this house has latterly been remarkable for several fatal duels. But to the purpose of prevention from fire. We have no word like the French "incendie," to signify the burning of a house, &c. Our word "fire" applies to the fire in the kitchen, parlour, &c.; but let that pass-to the purpose of this note. Mr. Hartley covered the ceilings of his rooms with very thin sheet iron, and in some cases the sides and floors. This is cheaper than lath and plaster, or handsome paper. The iron "Latine plate" can be painted any colour or pattern, and will resist all damp far better than plaster and paper. Pulled off one wall, it is as good as new to put on to another; in fact, if both sides of the plates be protected from the damp, by coal-tar or varnish, they must last to the end of the world." The best adjunct to this very excellent and perfect preventive from fire of Mr. Hartley's would be, the proposal I published, many years ago, in your invaluable Magazine, i. e. to construct the stairs of houses (when not of stone,) of iron. Sheet-iron for the steps; cast-iron for the balusters and supportings. But this, although at least as cheap as deal wood, will be opposed by the deal-mongers, who, of course, rejoice in the burning of deal houses and their inhabitants! the course of three years, the two houses of Parliament, six great mansions, and, I understand, the Royal Exchange and Tower armoury, have been consumed, owing to fire-flues being in contact with wood!! Now, a wise legislature would certainly inflict the very highest penalty of the law, whether death or transportation for life, on any architect or builder guilty of so stupid and reckless a conjunction! There is now a "Fire Preventive Company," of which I shall send you an account, when I can get at my papers. A patent for putting plaster on the walls of rooms! Ridiculous! Plaster". made of Roman cement and size! A

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combination I recommended in your Magazine in 1825. Are not 99 rooms out of 100 covered with plaster? The floors of our flimsily-built houses would not retain a coating of plaster, without its cracking to pieces in a week.

There is another point on the subject of prevention of house-burning which I will briefly mention. In the luminous, well-arranged, and comprehensive statistical account of the fires of London, yearly furnished to your Magazine by your benevolent Mr. Baddeley, it appears that the greater number of fires occur in the houses of licensed victuallers, i. e. public-houses. Now, our legislators are ever and anon exercising their legislative wisdom upon the publicans whom, it appears, they take to be the greatest

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sinners " in the community. I find that numerous fires occur from the contact of a candle with the bed-curtains, or window-curtains. Now, a good preventive law would be, to oblige all hotels and public-houses to have their curtains of any stuff, except cotton or linen. Wool and silk will not break out into a flame. It is useless saying that people should not read in bed, or place their candle on a dressing-table close to a curtain. They very often do so, and we see the consequences.

To those who cannot afford to change their cotton curtains for woollen or silk, I will suggest a sure preventive. After the curtains are washed, steep them in a solution of one pound of alum in one gallon, or rather more, of warm water; then hang them up to dry, after being wrung in the usual way. The same alum-water will do again-but alum is cheap.

Although my friend Mr. Hartley, the nephew of the inventor and the constructor of the fire-proof house on Wimbledoncommon, has lately published a comprehensive pamphlet on the conclusive experiments made in his uncle's house, such as piling faggots on the floors, six feet high, so as to cause a most intense fire, impinging on the ceilings, without either these, or the floors, or walls, being in the least injured, no attention has been paid by the public to so important an expedient. I will endeavour to send you a copy of this pamphlet, out of which you will, perhaps, be disposed to give some extracts to the public. I remember that, some years ago, Mr. Baddeley reiterated

the sheet-iron suggestion and practice of Mr. Hartley; but I was sorry to see that so sagacious a philosopher should have hinted that a ceiling of lath and plaster would resist fire nearly as well as the iron plates. I have repeatedly found, that beams of wood may be charred by fire, through iron plates; but it will not break into a flame, without the admission of a current of air.

"Prevention is better than cure" is, in the case of fires, the motto of, Sir, Your obedient servant,

MACERONI.

1, St. Martin's-place, Trafalgar-square. January 10, 1842.

MATTER AND SPACE.

Sir,-Permit me to make a few remarks, in reply to those of your correspondent "E.A.M.," on a paper of mine, inserted in the Mechanics' Magazine last December.

I can see nothing likely to appear "disputable" in the term medium of space it clearly designates locality and universality, and leaves its general utility inferable whereas, "firmamental fluid implies something of limited location and service. The firmament was made "to divide the waters from the waters"—" to divide the waters which were under the firmament from the waters which were above the firmament; and God called the firmament heaven." At present we know of nothing which agrees with the above description of firmament, but the atmosphere, which in no sense can be considered, like the medium of space, a universal cause.

I am much at a loss to understand what "E. A. M." means by a freezing principle. "Is not the medium of space the freezing principle, so long inquired about by philosophers?" A freezing element, or cause, is certainly more intelligible. The medium of space, by its pressure, expands water during congelation; it also expands water to overflowing of the vessel on a fire during ebullition. Its office is to move, expand, and to compress; and wherever these phenomena obtain, it is the cause. The material world has no other cause of action and effect. A freezing principle is as foreign to nature as a heating principle. Each phenomenon has its theory.

"E. A. M." asks, "Would it be pos

sible for motion to occur within the medium of space, if it did not itself undergo a chemical change?" Does this mean that a body cannot have motion in a fluid unless the fluid be acid or alkaline? A grain of shot descends, and a piece of cork ascends, through every kind of aqueous fluid; even through quicksilver, iron ascends. If density be implied, planetary motion would be maintained, as at present, were the medium of space liquid gold, and were impulse, as in all cases of motion, constant and greater than resistance. Besides, the medium of space is aeriform,-motion a mere mechanical effect; and chemical qualities and chemical change are but adopted expressions, conventional terms, which belong to the chemical art only. Mechanical nature knows nothing, includes nothing, needs nothing of chemical matter, chemical properties, or chemical qualities.

"The friction attendant on life," being capable of producing this chemical or physical change which would permit motion through the medium of space, is new, too new, indeed, to be comprehended at its origin. It may, however, be asked, did not the earth perform its motions as regularly before the creation of man, as now it does with 800,000,000 of human beings on its surface incessantly frictioning about; or, to be within the limits of history, were the earth's motions in the least affected when all mankind, but eight, were destroyed by the deluge? As I boast nothing of super-astronomical knowledge, I must beg information, how every movement of animal life tends to promote the circulation of the universe."

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"Heat and cold are, as every one knows, sensations: but are caused by different dispositions of matter." Then it were to be wished, the chemist would say, what it really is which boils, and what congeals, water, instead of misleading the world by attributing boiling to the sensation, heat-freezing to the sensation, cold; and otherwise, all modern philosophy sayeth not, as to how these phenomena are to take place. Different "dispositions of matter" causing heat and cold, is open to any kind of interpretion, so vague is the expression. However, “E. A. M." admits, that physical heat and physical cold are wholly out of the question. Still, I imagine, some consuming or corroding ability possessed by fire, some innate essential ability where

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by matter acts on matter is meant, but which cannot be correct. The atoms of matter and bodies are inert, therefore possess no self-acting ability whatever: they are unalterable, therefore are at this day the same in substance, size, shape, and essence, as the moment they were created; and bodies formed of them are as incapable of change from cold to hot, from hot to cold, from insipid to acidulous, as their inertia indicates, which includes unchangeability, and inertia is the zero of cause. Whatever is effected by fire, is effected only mechanically; nor is there in nature any but mechanical cause, mechanical effect, and mechanical result. The sensations which bodies promote seem to belong to those bodies; and thus is the simplicity of nature most strongly evinced in our being supplied, in sensations, with light, heat, cold, sound, acidity, and every thing our mind knows, without any thing similar belonging to the material world. Heat being admitted to be a sensation, what can "E. A. M." mean by "the sensation being caused by the motion of matter in the form of heat?" Shape and feeling are vastly different things.

The nervous fluid is the cerebral sense exciting cause in every instance, no matter what may be the resulting sensation. The medium of space is continuous from without through the nerves of sensation to the brain, and within the nerves it is the nervous fluid. As its pressure on the brain, promoted by external circumstances, increases, so is the sensation, heat, excited and increased; when the pressure is intense, the sensation is pain accompanied with rupture of blood-vessels; and as the pressure declines to the minimum, the sensation is cold, colder, and painfully cold. I would ask "E.A. M.," from having granted that heat and cold are but sensations, how "cold is caused by the presence of more of the medium of space than the vital energy can convert into heat?"-into the nonentity heat, or even the sensation, it being impossible, by all the energies of nature, to convert matter from what it is, to any state it is not, but as respects rest, motion, or locality.

All sensations are the mental result of the pressure, and degrees of pressure, of that portion of the medium of space which forms the contents of the nerves of sensation, on the respective organs of the

brain. "Recollection of a sensation," of pain, for instance, is not a sensation. "E. A. M." is perfectly correct, if, in saying, that, "a white leaf and a black dye might express all the wonders of creation," is to be understood, that the theory of nature is so simple, any single phenomenon comprehended fully makes known the general theory. For, however diversified are nature's mechanical performances, (made tenfold so, to us, by the sensations they promote,) how far from complex must be the theory of a procedure, however universal, which has for substance only inert homogeneous atoms; and for cause, only pressure emanating from the general construction. T. H. PASLEY.

Jersey, January 8, 1842.

ON MR. R. ARMSTRONG'S NEW THEORY OF DIFFUSION. BY C. W. WILLIAMS, ESQ.

Sir,-As you have given the publicity which your columns ever secure, to Mr. R. Armstrong's new and ingenious illustration of Dr. Dalton's theory of the peculiar manner in which gaseous bodies intermingle, termed, their "diffusion;" and as Mr. A. has demonstrated, (to his own satisfaction, at least,) in the working of Mr. R. Cheetham's smoke-burning patent, that Dr. Dalton's system of the diffusion of gases, inter se, means, in fact, their absolute separation from each other, it will be at least curious to know how this very original conception of the process of diffusion" is made out and applied.

I have said, this new theory of Mr. A. is ingenious; indeed, I can only compare it to the process by which the philosopher would explain to the Prince of Abyssinia how to extract sun-beams from cucumbers. All that was wanting to prove Mr. Armstrong's theory, (and which I have no doubt he will supply, suo more,) was, to have added an algebraic formula, thus to establish the fact, that it was "mathematically correct."

Mr. A. tells us, that "it was with peculiar pleasure he lately heard" (three years ago this patent was explained in Mr. A.'s own book,) "of a most interesting application of chemical laws, in the newly-discovered process for burning smoke and economizing fuel, by Mr. Cheetham, by which those two important objects are effected in a manner far su

perior to any thing of the kind that has ever been seen before." The "particular chemical laws thus applied" being those of Dr. Dalton, relating to the diffusion of gases! And now for the theory and its application. Mr. Cheetham's plan, Mr. A. tells us, "consists in the compelling all, or most, of the carburetted hydrogen and other combustible gases, which escape inflammation, when first generated from the crude coal in the furnace, to return again, and pass through the fire, where they are converted into flame."

I would here stop just to ask a simple question, whether it might not be as well to effect the combustion of these gases at once, and by a single operation, thus avoiding the second circuit of the furnace and flues? The only reason which suggests itself for this burning but one portion of those gases in the first instance, and then ingeniously bringing the other portion round again by the circulating process is, that if all had been burned at the first operation, then would there have been no need or application for the new theory; for theories, as well as candles, were not invented to be put under bushels.

Mr. A. then informs us, that this process is effected by a very simple apparatus, namely, by a "small rotary fan, in connexion with that part of the flue through which the smoke is passing off to the chimney, after having left the boiler." I would here again ask, why make this smoke at all? and why burthen the flues and the boiler with this second current of so bad a heat conductor as smoke or soot? Except, indeed, for the pleasure of illustrating the new theory.

We are then told that the fan "ezhausts the smoke from the smoke-flue, and propels it, by a return flue, to the inclosed ash-pit, whence it is forced through the fire-grate, where combustion (of this smoke) is effected, and the products of this second combustion (second combustion!) again passes under and around the boiler, and then up the chimney." A casual observer would here ask, how this smoke, so exhausted from the smoke-flue, after the first and second processes, and after having made this second circuit round the boiler, is prevented from making a third circuit along the same ground; and, in fact, making a sort of squirrel-cage move