Lapas attēli
PDF
ePub
[merged small][merged small][merged small][graphic][subsumed]

perforated to correspond, (the aperture being usually closed by a cushion); the pan slides under the bedstead, and the patient is gently placed (by the cylinder) on his side, and the cushion removedthis effects a direct opening to the pan, and the patient is replaced on his back.

The advantages of the bedstead are stated to be the following:

1st. By it a patient may be elevated at the shoulders to any pitch desired. 2nd. The knees may be raised to assist in sustaining the weight of the body. 3rd. The whole frame of the bedstead may be raised so as to assume a perfect chairform, when the apparatus for raising the knees becomes the seat of the chair. 4th. The trouble and evils attendant on the introduction of a bed-pan are obviated. 5th. Bed-ridden and weakly patients are turned from side to side, as may be wished; or on the face when operations and dressings on the back are necessary. And, lastly, an entire change of bedding

is effected in one minute; and above all things be it observed, that every one of these operations of raising and lowering, turning and changing, are made without so much as touching the patient, and with an ease and a readiness calculated to soothe pain, instead of annoying or irritating the sufferer. The sacking of the bedstead being stretched upon spring rollers, imparts a most agreeable elasticity of action at every motion of the patient; while the operations of reading and writing, and the adminis tering of food and medicine, are, by the various movements of which the bedstead is susceptible, greatly facilitated.

We understand that Mr. Cherry, the meritorious inventor, died soon after se curing the patent. We hope that his widow and children will reap the benefit of his ingenuity. A model, we are informed, may be seen at the Adelaide Gallery; and the bedstead itself, by application to Mr. W. C. Lewis, 23, Lei, cester-square.

3

388

MACKINTOSH'S ELECTRICAL THEORY OF THE UNIVERSE.

MACKINTOSH'S ELECTRICAL THEORY OF
THE UNIVERSE.

Sir, There is an old saying, that "there are none so blind as those who will not see." Kinclaven first infers from

upon the principles of universal gravita-
tion, but which may upon electrical prin-
ciples, then we are compelled to reject
gravitation, and to adopt the electrical
hypothesis, at least so far as respects those

the
passage
trical theory is asserted to be in accord-
ance with the laws of Kepler, and when
reminded that no statement has been
made with respect to its agreement or dis-
agreement with any law whatever, he be-
takes himself to the other alternative, and
infers that it is not in accordance with
those laws; and concludes his observations
on that head by saying, "if the electrical
theory is at variance with Kepler's laws,
it is equally so with the Newtonian sys-
tem." Perhaps Kinclaven will find in
the end that it is not at variance with
either the one or the other; that the elec-
trical theory is an extension of the prin-
ciple of universal gravitation; and that,
with some qualifications, it is in perfect
accordance with the laws of Kepler. The
statements which have been made are
general and indefinite, and, of course,
under such circumstances those who are
predisposed to cavil may draw inferences,
so as to make the theory agree or dis-
agree with any law whatever. If Kin
claven will not understand, we must at
least endeavour to put the matter in a
shape sufficiently plain that the general
reader may not be misled by his misre-
presentations. "From the most careful
analysis of the phenomena of electric at-
traction, it has been deduced that the
exact law of this force is the same as that
of gravitation, namely, that its intensity
is inversely as the square of the distance."

particular instances.
he has quoted that the elec-

"The mode in which the electricity imparted to a conducting body, or to a system of conductors, is distributed among its different parts is in exact conformity to the results of this law, as deduced by mathematical investigation." Now, if we find that the ordinary phenomena ascribed to gravitation may be referred with equal propriety to electrical attraction, then either hypothesis may be adopted indifferently. If we find particular instances in which the phenomena are better explained upon electrical principles, we are induced to give the preference to the electrical hypothesis in those ins nces, without perhaps rejecting gravitation altogether. But if we find, upon ex mining the phenomena more closely, some instances which cannot be explained

In all cases if both

forces follow the same law, the demonstrations cannot be affected by merely changing the terms. But if we adopt the electrical hypothesis, this includes the supposition that the earth is charged with electricity, and this brings us to another point in Kinclaven's letter.

It

He says, "I will ask Mr. M. is he cer tain of the existence of an electrical fluid." We are bound to suppose that Kinclaven is serious in asking this question. Bishop Berkeley denied the existence of matter; in doing which his seriousness has not been questioned, although some doubts have been entertained with respect to his sanity. However, let us not misrepresent Kinclaven; he has not denied the existence of an electric fluid, although we might draw that inference with quite as much propriety as has been done on his part with respect to the laws of Kepler agreeing or disagreeing with the electrical theory. Kinclaven having put the interrogative cautiously, brings forward Sir John Leslie with some "remarkable observations." This designation is quite appropriate. It must be allowed that the observations of Sir John are somewhat remarkable. is also remarkable and worthy of observation, that they happen to be published in a Number of the Mechanics' Magazine which contains their complete refutation by the able and, we may add, wonderful results (although they are not new) of the experiments of Messrs. Fox and Cross, as detailed at the Bristol meeting of the British Association. might Professor Sedgwick exclaim, that "the operations of electrical phenomena proved that the whole world, even darkness itself, was steeped in everlasting light, the first-born of Heaven." Whatever Kinclaven may think about the existence or non-existence of an electric fluid, he will not be hardy enough to deny that there are certain effects which have been ascribed to the action of an electric fluid, and which cannot be explained on any other hypothesis. Although Kinclaven is attacking the electrical theory with more asperity than to me appears needful, I hope he will never have the

Well

MACKINTOSH'S ELECTRICAL THEORY OF THE UNIVERSE.

existence of the fluid proved to him by the argumentum ad hominum from electricity itself. Kinclaven ought_to know, that putting interrogations is a dangerous mode of discussing a question, because the respondent sometimes lays claim to the same prerogative. Can Kinclaven give a definition of gravitation per se, excluding the idea of matter?

Kinclaven says, "La Place has demonstrated that gravity darts its influence more than fifty million times faster than light; and sets for ever at rest the va rious speculative attempts to explain the cause of attraction by the agency of certain mechanical intermedia, and proves it to be a primordial and ultimate principle, ordained by the wisdom of the Supreme Architect." Now, Kinclaven must know, that all this is nothing, more or less, than sublime nonsense. By what intuition has La Piace arrived at a knowledge sufficient to enable him to determine primordial and ultimate principles? Does Kinclaven imagine that the progress of inquiry in that direction is to be for ever arrested by the interposition of vague and pompous assertions signifying nothing? It might be much more safely asserted, that men will never arrive at primordial and ultimate principles; that there is no resting-place for the human mind.

An objection has been taken to the Newtonian philosophy, to which Kinclaven has deemed it expedient to make no reply:-That as the force of gravity acts against the momentum, the undiminishable must destroy the diminishable force within a given and not a very extended period of time. But we may take an objection on still higher grounds.

The Newtonian philosophy assumes that the motion of the planets is simply the continued effect of an original impulse imparted to them at the creation. Is this philosophy? Where is the demonstration? Where are the analogies? It is the philosophy of the trembling savage, who traces all physical effects to one unknown cause; the great connecting chain of cause and effect is almost wholly hid from his eyes. And because we have discovered a few of the inferior links (by far the larger portion being still obscured from our vision), it is confidently announced that we have arrived at a knowledge of primordial and ultimate principles. It is a natural tendency of the human mind thus to imagine. When

389

we have traced from the effects to the causes till we can trace them no further, we speculate for a time upon the probable cause, but finding the problem insoluble, we cut the Gordian knot, we break the chain of cause and effect, and at once connect the whole of these effects with one unknown cause-presumptuously imagining that we have arrived at a knowledge of primordial and ultimate principles. All the operations of the Supreme Architect are consummated by the interposition and agency of secondary causes, by certain properties which she has been pleased to impress upon the elements of the material creation. It is the province of philosophy to trace and discover those properties and secondary causes, and by thus extending our know ledge of the things of nature, we are enabled to make them subservient to the well-being of man. Thus far may phi losophy go, and no further. Whenever we advert to Divine Power for a solution of natural phenomena, we virtually confess that we have arrived at the limits of known causes-the boundary which se parates the known from the unknown. Therefore, the gratuitous assumption, that the motion of the planets is the continued effect of an original impulse, is a virtual confession of our ignorance of the cause of that motion.

It would be as well if Kinclaven would give satisfactory answers to these two objections before he proceeds to judgment upon the electrical theory; until be has done so, all his flourishes about rigid demonstration are mere bombast.

I perceive that the electrical theory has received an attack from an "Old Correspondent"-but as he has very candidly confessed that he is totally ignorant of the subject, of course he does not require to be answered. He should have informed himself, however, a little better before he ventured to give an opinion, "that it is all nonsense."

Your obedient servant,

T. S. MACKINTOSH.

P. S.-I intended to have made a few

remarks upon "the precession of the equinoxes being one of the perturbations that tend to give an eternal stability to the system," but perhaps it may be as well to let them stand over for the present; let us settle the point in hand first. In the mean time, I would recommend Kinclaven to take into his consideration

390

MESSRS. UPTON AND ROBERTS' SAFETY-LAMP.

the progressive motion of the apogee in connexion with the supposition of the earth's motion in a spiral orbit.-T. S. M.

MESSRS. UPTON AND ROBERTS' SAFETYLAMP.

[ocr errors]

Sir, While such a difference of opinion exists on so important a subject as the safety of the Davy-lamp, it would be well that those who have the opportu nity of proving it in practice, should communicate the result of their experiments to the public.

I am the more particularly induced to make this suggestion, from having remarked in Mr. Pereira's examination (vide Mechanics' Magazine, vol. xxiv. p. 338,) the following question and answer as referring to Messrs. Upton and Roberts' lamp:- "Have you made any experiments in coal mines with it? No, I have never been in a coal mine with it."

To this question, Mr. Editor, I am prepared to give a different answer, having since the publication of the evidence alluded to, had many opportunities of trying in practice the merits of the improved lamp, the safety of which I am enabled to confirm from repeated proofs of the unfailing property it possesses of destroying internal combustion before the wire becomes heated to a state of danger.

In my experiments with Messrs. Upton's lamp, I would beg to observe, that I have also usually had with me a common Davy lamp, by which I have proved the important fact that the latter is still safe after the improved lamp is extinguished, having proceeded several yards with the Davy lamp after the other was put out, the inflammable gas repeatedly exploding within the cylinder.

The advantages of Messrs. Upton's lamp in practice appear to be these: increased light, greater security of the gauze from external injury, steadiness of the flame while travelling rapidly, or in passing through currents of air, and lastly, the impossibility of internal combustion being continued so as to endanger the fusion of the wire. The disadvantages of this lamp (for these it undoubtedly possesses,) are its great weight 3lbs., and inconvenient height, 15 inches, both of which might, I think, be remedied in the construction without interfering with those principles which conduce to its safety. I think it will also be found that

in the critical examination of workings where a viewer has to determine the safety of introducing candles, the com mon Davy will be preferred, as the glass prevents that nice observation of the flame within the lamp, which guides the experienced miner in his vitally important decision.

These crude remarks will, I fear, ap pear unworthy of a place in your valuable Journal, and to obviate this in future, I would suggest that communications of this nature might be rendered more va luable were some of your scientific cor. respondents to propose such a list of questions as might appear most important to be answered from results obtained from inflammable gas as actually evolved in mines by the inscrutable operations of nature, and differing, as there is too much reason to suppose it does, from the most carefully manufactured approximations of our ablest chemists.

I am, Sir,

Your very humble servant, THE BLACK DIAMOND. Kilburne, near Derby, Aug. 31, 1836.

A SIMPLE METHOD FOR DRAWING ON BOTH SIDES OF A BOARD WITHOUT EITHER BEING RUBBED.

Sir, If the simplicity of any plan do not take away from its utility, perhaps the following contrivance (which occurred to me from reading one which bad the same object in view in your Magazine), may on that score be acceptable. It is not at all unusual for draftsmen to be working at two different drawings at the same time; and in this case it would be very convenient to make one drawing-board answer in the place of being obliged to have two.

To effect this, I think that two slips of wood of the same thickness, provided with pins, say two at each end, and these made to fit in corresponding holes in the drawing-board at top and bottom, would be sufficient for the purpose. By these means a sheet of paper could be laid on both sides the board, and he used at the same time by reversing the pieces of wood from one side to the other, as occasion may require. The holes should be near the edge of the board to allow as much room as possible for the paper.

I cannot vouch for the originality of the above, as being so plain it may have

EXTINCTION OF RIVER-SIDE FIRES.

occurred to, and even been adopted by, many; but it has not come under my observation.

August, 1836.

I remain, Sir, Very respectfully yours,

FREDERICK LUSH.

EXTINCTION OF RIVER-SIDE FIRES.

Sir, I have been much interested by the various contrivances published in your valuable Magazine for preventing the deplorable calamities attendant upon fires. The recent event at London Bridge has suggested to me a mode by which fires in the vicinity of the river may be more readily extinguished. It is simply this: Let one, two, or more floating steam fire-engines be moored at different stations on the river, each fitted up with paddle-wheels, and having every requisite, such as fire-escapes, &c., on board, and let them be always ready for use. The facility with which they might be brought to the scene of action at any state of the tide,* and the immense body of water which a small steam-engine would be enabled to throw upon a fire when its paddles were not at work, together with the frequent scarcity of water for the supply of land-engines, even near the river, induce me to believe they would be highly advantageous. The expense, either for first cost or keeping up a supply of steam, I do not think would be objected to, when we reflect on the loss of property which might probably have been prevented within no very distant period, near to or upon the river and the docks, if only one floating steam fireengine‡ had been regularly stationed at

The present floating-engine (by the report published in the Chronicle) did not reach the fire until two hours after it broke out; and although highly efficient on its arrival, it is awful to contemplate the amazing increase of a fire during such a period, and the relative difficulty of extinguishing it, in proportion to the length of time from its commencement.

The loss at London Bridge, by the report above referred to, is estimated at about half a million sterling.

Among other advantages likely to arise from the adoption of engines of this description, I think they might have a common fire-engine on board, with convenience for landing it in situations which could not be approached from the land side, where they could be effectively used; but I must beg to refer all details to the consideration of those more practically acquainted with the subject than myself.

391

[blocks in formation]

FIRE-PROOF STAIRCASES.

Sir,-Among the various schemes for preventing the sad havoc which is so frequently the consequence of fires (in two many instances attended with loss of life or mutilation of limb), that which to me appears the most simple and the most efficacious is scarcely ever noticed, and I much fear will never be acted upon generally without legislative interference-I mean the construction of incombustible staircases. I am a builder in a small way, and being an operative mason, have always, without reference to the size of the house, put stone, or stone and brick to the first floor; even in fourth-rate houses this is quite easy, and little more expensive than wood. Two courses of brick for riser, and a rubbed York tread with the nosing rounded; the bricks faced with cement, and when dry painted stone colour. This looks well, and is lasting. Nearly all fires originate in the lower part of the house; and a moment's reflection will convince every one of the difficulty of the flames reaching and burning through a ceiling eight or nine feet high, except by means of communication afforded by the wooden staircase. Above the first floor, stone staircases, unless geometrical, are more difficult, on account of the necessary support taking up too much room. My present object is, however, to point out the advantage of having the lower staircase fire-proof, which perhaps would, in 99 cases out of 100, prevent the fire reaching higher if it commenced on the ground-floor, or afford an easy mode of escape should the fire take place in an upper story.

I remain, Sir,
Yours, very truly,

Obelisk, Sept. 5, 1836.

P. RAYNER.

« iepriekšējāTurpināt »