THINGS TALKED OF IN LONDON.

_July 1852._

When we shall have a constant supply of pure water--a complete system

of efficient and innoxious sewers--a service of street hydrants--when

the Thames shall cease to be the _cloaca maxima_, are questions to

which, however seriously asked, it is not easy to get an answer. Add

to these grievances, the delay of proper regulations for abolishing

intramural interments, and the fact that Smithfield is not to be

removed further than Copenhagen Fields--a locality already surrounded

with houses--and it will occasion no surprise that the authorities are

treated with anything but compliments.

The laying down of an under-sea telegraph wire across the Irish

Channel, may be taken as a new instance of the indifference consequent

on familiarity. When the line was laid from Dover to Calais, the whole

land rang with the fact; but now the sinking of a wire three times the

length, in a channel three times the width, excites scarcely a remark,

and seems to be looked on as a matter of course. The wire, which is

eighty miles in length, is said to weigh eighty tons. It was payed out

and sunk from the deck of the _Britannia_, at the rate of from three

to five miles an hour, and was successfully laid, from Holyhead to

Howth, in from twelve to fifteen hours; and now a message may be

flashed from Trieste to Galway in a period brief enough to satisfy the

most impatient. The means of travel to the East, too, are becoming

tangible in the Egyptian railway, of which some thirty miles are in a

state of forwardness, besides which a hotel is to be built at Thebes;

so that travellers, no longer compelled to bivouac in the desert, will

find a teeming larder and well-aired beds in the land of the Sphinxes.

And, better still, among a host of beneficial reforms to take place in

our Customs' administration, there is one which provides that the

baggage of travellers arriving in the port of London shall be examined

as they come up the river, instead of being sent to the Custom-house.

By a report of the Astronomer-royal to the Board of Visitors, who have

lately made their annual inspection of the Greenwich Observatory, we

are informed, of a singular fact, that observations of the pole-star

shew that its position varies some three or four seconds on repeating

the observations at intervals of a few months, and this

notwithstanding the extreme accuracy of the transit circle. The only

explanation which can as yet be given for this phenomenon is, that the

earth, solid as it appears, is liable to slight occasional movements

or oscillations.

We shall know, in a few weeks, the result of the telegraphic

correspondence with the Observatory at Paris--one interesting point

being, as to whether the respective longitudes, as at present

determined, will be verified by the galvanic test. Besides which,

Greenwich time is to be sent every day to London, where a pole, with a

huge sliding-ball, has been fixed on the top of the Telegraph Office,

near Charing Cross. This ball is to be made to descend at one o'clock

simultaneously with the well-known ball which surmounts the

Observatory; and thus scientific inquirers--to say nothing of the

crowds who will daily throng the footways of the Strand to witness the

downcome--will be informed of the true time, while, by means of the

wires, it may be flashed to all parts of the kingdom.

The lecture with which Professor Faraday wound up the course at the

Royal Institution may be mentioned here, seeing that it adds somewhat

to our knowledge of the theory and phenomena of magnetism. As usual,

the lecture-room was crowded; and those who could not understand, had

at least the satisfaction of being able to say they were present. Mr

Faraday, who, enlarging upon his view, announced, a short time since,

that there are such things as magnetic lines of force, now contends

that these lines have a 'physical character'--a point most

satisfactorily proved by sundry experiments during the lecture. The

inquiry is one, as Mr Faraday observes, on the 'very edge of science,'

trenching on the bounds of speculation; but such as eminently to

provoke research. The phenomena, he says, 'lead on, by deduction and

correction, to the discovery of new phenomena; and so cause an

increase and advancement of real physical truth, which, unlike the

hypothesis that led to it, becomes fundamental knowledge, not subject

to change.' A chief point of discussion to which the investigations

have led is: Whether the phenomena of what we call gravity may not be

resolvable into those of magnetism--a force acting at a distance, or

by lines of power. 'There is one question,' continues Mr Faraday, 'in

relation to gravity, which, if we could ascertain or touch it, would

greatly enlighten us. It is, whether gravitation requires _time_. If

it did, it would shew undeniably that a physical agency existed in the

course of the line of force. It seems equally impossible to prove or

disprove this point; since there is no capability of suspending,

changing, or annihilating the power (gravity), or annihilating the

matter in which the power resides.' The lines of magnetic force may

have 'a separate existence,' but as yet we are unable to tell whether

these lines 'are analogous to those of gravitation, acting at a

distance; or whether, having a physical existence, they are more like

in their nature to those of electric induction or the electric

current.' Mr Faraday inclines at present to the latter view. He

'affirms' the lines of magnetic force from actual experiment, and

'advocates' their physical nature 'chiefly with a view of stating the

question of their existence; and though,' he adds, 'I should not have

raised the argument unless I had thought it both important and likely

to be answered ultimately in the affirmative, I still hold the opinion

with some hesitation, with as much, indeed, as accompanies any

conclusion I endeavour to draw respecting points in the very depths of

science--as, for instance, one, two, or no electric fluids; or the

real nature of a ray of light; or the nature of attraction, even that

of gravity itself; or the general nature of matter.' These are

profound views; but we may reasonably conclude, that, however obscure

they may at present appear, they will in time be cleared up and

further developed by the gifted philosopher from whom they emanate.

Of minor matters which have been more or less talked about, there is

the Library for the Working-Classes, just opened in the parish of St

Martin-in-the-Fields--a praiseworthy example for other parishes, but

not to be followed unless the readers actually exist, and manifest the

sort of want which books alone can satisfy. A suggestion has been

made, to use for books in hot climates, where paper is liable to rapid

decay, the sheet-iron exhibited at Breslau, which is as thin and

pliant as paper, and can be produced at the rate of more than 7000

feet to the hundredweight. This would be something new in the

application of metal. Metallurgy generally is being further

investigated by Leonhard of Heidelberg, who has just called on

manufacturers to aid him in his researches, by sending him specimens

of scoriæ, particularly of those which are crystallised. Then there is

Mr Hesketh's communication to the Institute of British Architects, 'On

the Admission of Daylight into Buildings, particularly in the Narrow

and Confined Localities of Towns;' in which, after shewing that the

proportion of light admitted to buildings is generally inadequate to

their cubical contents, and means for estimating the numerical value

of that which really does enter, he states that the defect may be

remedied by the use of reflectors, contrived so as to be 'neither

obstructive nor unsightly.' He explains, that 'a single reflector may

generally be placed on either the outside or inside of a window or

skylight, so as to throw the light from the (perhaps small) portion of

sky which remains unobscured overhead, to any part in which more light

is required.' Such difficulties of position or construction as present

themselves, 'may be overcome in almost every case, by, as it were,

cutting up the single reflector into strips, and arranging them one

above the other, either in the reveal of the window, or in some other

part where it will not interfere with ventilation, or the action of

the sashes.' This is adopting the principle on which improved

lighthouse reflectors are constructed; and we are told, that 'the

combinations may be arranged horizontally, vertically, or obliquely,

according to the positions of the centre of the unobscured portion of

sky, and of the part into which the light is to be thrown, and

according to the shape of the opening in which the combination is to

be placed.' As a case in point, it was mentioned that a reflector 'had

been fitted to a vault (at the Depôt Wharf, in the Borough) ninety-six

feet in depth from front to back. The area into which the window opens

is a semicircle, with a heavy iron-grating over it; and the result is,

that small print can be easily read at the far end of the vault.' It

is a fact worth knowing, that reflectors may be so constructed as to

throw all the available daylight into any required direction; and in

one instance the reflector may be made to serve at the same time as a

dwarf venetian window-blind. Instead of wooden splats or laths, flat

glass tubes or prisms are used, fitted into the usual framework, and

these being silvered on the inside, throw all the light that falls on

them into the room, when placed at the proper angle.

Again, the possibility of locomotion without the aid of steam is

talked about, and the New Yorkers are said to be about to send over a

large ship driven by Ericsson's caloric engine, which is to prove as

powerful as vapour at one-half of the cost--a fact of which we shall

be better able to judge when the vessel really arrives. Then, looking

across the Channel, we find the Abbé Moigno proposing to construct and

establish a relief model of Europe in the Bois de Boulogne at Paris,

of a size to cover several acres, and with the railways of iron, and

the rivers of water, by which means one of the most interesting and

instructive of sights would be produced, and the attractions of the

Trench capital greatly increased. A desirable project--but the cost!

The Montyon prize of 2000 francs has been awarded to M. Mosson, for

his method of drying and preserving vegetables for long sea voyages,

as published a few months ago. M. Naudin states, that a certain kind

of furze or thistle, of which cattle are very fond, may be made to

grow without thorns--an important consideration, seeing that at

present, before it can be used as food, it has to undergo a laborious

beating, to crush and break the prickles with which it is covered. As

the plant thrives best on poor soils, which might otherwise lie

useless, the saving of this labour will be a great benefit to the

French peasantry; and the more so, as it appears the plant will grow

in its new state from seed. M. Naudin believes, that the condition of

other vegetable productions may be varied at pleasure, and promises to

lay his views shortly before the Académie. M. Lecoq, director of the

Botanical Garden at Claremont, informs the same body of something

still more extraordinary, in a communication, entitled 'Two Hundred,

Five Hundred, or even a Thousand new Vegetables, created _ad

libitum_.' Having been struck by the fact, that the ass so often feeds

upon the thistle, he took some specimens of that plant, and, by

careful experiment, has succeeded in producing for the table 'a

savoury vegetable, with thorns of the most inoffensive and flexible

sort.' Whatever be the kind of thistle, however hard and sharp its

thorns, he has tamed and softened them all, his method of

transformation being, as he says, none other than exposing the plants

to different influences of light. Those which grew unsheltered, he

places in the dark, and _vice versâ_. Familiar examples are given in

the celery, of which the acrid qualities are removed by keeping off

the light; while the pungency of cress, parsley, &c., is increased by

exposure to the sun. M. Lecoq has not yet detailed all his

experiments; but he asserts that, before long, some of our commonest

weeds, owing to his modifications, will become as highly esteemed as

peas or asparagus. Let him shew that his process is one that admits of

being applied cheaply and on a large scale, and he will not fail of

his reward.

Chambers's Edinburgh Journal, No. 448 Volume 18, New Series, July 31, 1852 · 第 9 / 16 题