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KATER'S PENDULUM.'

285 then with the other, so that the times KATER'S PENDULUM.

of oscillation in both cases are equal, the distance between these two cen. tres will be the length of the equivalent simple pendulum, whatever be the irregularities of form or composition in the instrument. The manner in which this effect was producent was as follows:-A brass pendulum, CD, was furnished with two axles, from which it could be suspended, one passing through C, and the other through 0. Besides the principal weight, D, it was provided with a smaller sliding weight, F, which could be moved along the stem, CD; and this weight was to be moved till the number of oscillations, in a given time (as 24 hours), was the same whether the pendulum was suspended from C or from 0. F was placed in such a position, that, by moving it from O as to F, the number of oscillations about C, in twenty-fours, was increased; and by the same change the number of oscillations about O, in the same time, was still more increased. The adjustment was thus made :-Let the weight be at F, and let the number of oscillations in ten minutes, about C, be 606, and about O be 601 ; now let F be moved to f, and let the oscillations in ten minutes be 607 about C, and 609 about O (because the latter are more af. fected than the former); then the

proper position of the slider is some"SIR, -As many of your readers where between F and f. Let it be may be ignorant of the principle of placed atf, biseçting Ff, and let the this instrument, I send you the fol- oscillations in this case be 6061 and lowing extract from Whewell's Me- 606; then the proper position is chanics

between F and f, and so on.. Ob" In order to find the length of a serving always, that if the number second's pendulum, we must find the

of vibrations about C be greater, the distance between the centres of sus.

slider must move towards C; and if pension and oscillation of the oscil.

the contrary, it must move towards lating body. The difficulty is to de

0. By this means, continually halving termine the latter point, on account

the distance last moved, we may of irregularities of density and figure.

make the oscillations about C and

O approach within any required de" To avoid these sources of inac

gree of exactness; the distance becuracy, Captain Kater has employed tween C and O being then measured, the property of a compound pendu. will give the length of a pendulum lum, to prove that the centres of which makes a known number of suspension and" oscillation are re. oscillations in ten minutes.". ciprocal. It follows, from that pro

. I am, Sir, perty, that if a pendulum have two centres of suspension and oscillate on

Yours respectfully, them, first with one end uppermost,

. F. R. A.

286

PERPETUAL MOTION. A PLAN DESIGNED TO ACCELERATE to its practicability, it would be lookTHE DISCOVERY OF PERPETUAL

ed upon as an empty boast, were I to

assert that the discovery is already · MOTION.

made*; 1 will therefore only venture Sir,So much has of late been to propose the following plan, which said on this subject, that, in all pro- appears to me likely to expedite só bability, many of your readers are desirable an objeet. '* heartily tired of it, and will treat Let 'some well-known public-spiritwhat I am about to advance with the ed individuals commence a subscripgreatest contempt. However, since tion, and apply the produce to the all that has or can be said will not erection and furnishing of separate amount to a proof of its impossibi- work-shops, expressly for the use of lity, perhaps some of those who are those who do not possess the means in the habit of thinking for them of putting to the test of experiment selves may not yet be quite convinced any design they may conceive likely that it is such.

to produce the desired effect. Every To them I would say, let us for a model made in these shops will be moment reflect how much the long long to the Institution, and should be list of impossibilites has of late years preserved and properly arranged been reduced, and then ask ourselves, in a convenient place, appropriated if we have not reason to hope for a exclusively to their reception. I will still further reduction ? A few years not trespass on your valuable pages back, it was impossible to raise our by specifying the rules, &c., appliselves more than a few feet from the cable to such an Institution, or by earth, or to immerse ourselves with pointing out its advantages, further safety in the depths of the ocean; and than to observe, that if it were only it was equally impossible to traverse to produce a collection of unsuccessits surface to any extent, unless fa ful models, accessible to the public, it voured by wind or tide. We can now, would be highly beneficial, ás iti however, soar above the clouds, ex- would be the means of preventing plore the depths of the ocean, and any further waste of time and money skim over its surface, in spite of wind on what had already proved ineffecand tide. And be it for ever remember- tual. But it can scarcely be supposed ed, that we owe these and many other that it would fail to contribute mates! advantages to a few persevering rially to the progress of science; and individuals, who were, in all probabi- as the whole cominunity participate lity, stigmatized as chimerical vision in the advantages derived from sciaries by those who seem to have an ence, so every individual (however unconquerable propensity to con- deficient in original ideas) may, by demn every thing above the level of supporting this Institution, bave the their own understanding.,

gratification of contributing to its) If by perpetual motion nothing advancement: ,5 JA 934 of qiii more is meant than the putting in Such an Institution would be an motion some of the most durable honour to the country, and though it substances with which we are ac- may not produce the desired effect, quainted, in such a manner as to enit would doubtless be the means of sure a continuance of that motion as making many valuable additions to long as those substances will resist the our present stock of mechanical effects of time and friction, I do not knowledge, and we should not, as, despair of seeing it accomplished. was the case with the discovery of Our rapid advances in scientific the New World, have tlie mortifica.. knowledge, together with the advan- tion of seeing it achieved by means tages likely to be derived from the “ British Invention Company,” give

T

E 5 TO 771 us reasonable ground to hope, that * The person who can raise a weight the time is not far distant, whien even of six ounces to the height of thirteen

hot and a half inches, merely by the descent severing ingenuity. In the present to be allowed to assert that the discovery

of four ounces only twelve inches, ought state of public opinion with regard' is made.

SUSPENSION RAILWAY-ELECTRICAL EEL.

287 of the patronage and support ob- each other, varying in height accordtained from another nation, after it ing to the undulation of the ground, had in vain been solicited from us. so as to keep their upper extremities And here let me remind your reader, parallel with the necessary plane. that it was the outcry set up by the In a cleft on these are laid reverse Antivizionaries, Antichimericals, and wedges, on which rests a line of bearCo., those inveterate foes to every ers of wood, the upper surface of kind of discovery and improvement, which, covered with a plate of iron, that deprived us of the honour and forms the road for the passage of the emolument derived from that brilli- wheels. The average height of this ant discovery, and who still continue road above the ground is from two to to do more injury to society in one three feet. The carriage has two year, than has ever been done by the wheels, one placed before the other, visionaries in a whole century. I and two receptacles for goods, which cannot conclude without expressing are suspended, one on each side, the my unqualified approbation of the centre of gravity being below the Mechanics' Magazine. May it ever surface of the rail. A number of continue a vehicle of conflicting opi. these carriages are linked together by nions, until we arrive at truth on every chains, and a horse is connected with subject, is the sincere wish of, Sir, the whole by a towing-rope attached Your very obedient servant,

to the foremost machine. The most L'ins a "v? PERSEVERANTIA.

striking peculiarity of this plan is Worfield.

its extreme simplicity, considering the many obvious advantages it pre

sents beyond the ordinary double to

rail-road, particularly the great exSUSPENSION RAILWAY. pense it avoids in embankments, culSIR -As the subject of Railways verts, and drains; the trifling space has-lately been much agitated, and of ground it occupies; the increased the attention of the public turned to effect which can be produced upon it, them in no small degree, perhaps it from its reduced force of resistance; would not be amiss to give place, in its comparatively small cost ; its fayour valuable Magazine, to the fol. cilities of loading and unloading, &c. Sowing abridgment of a newspaper pa. Each carriage contains an oblong ragaph; it will be only a companion box (for passengers or goods), susto a late paper on the subject, to which pended on either side of the rail line, you have given place; and by its in and a quantity of bricks is stowed sertion you will not only oblige an beneath the seats for ballast; thus one old correspondent, but perhaps many horse drew forty passengers, besides more, who, having time and inclina- an immense weight of bricks. One on, would feel a pleasure in taking a carriage, which has been constructed trip to see it, the distance not being for the purpose of trying the applivery great."

cation of the plan to the conveyance of

passengers, differs from the others. “A line of railway on the suspen- Its boxes partake partly of the shape sion principle, invented by Mr. H, of a

of a gig, and partly that of a balloonR. Palmer, has been constructed for car: in

car; in each are two cushioned seats practical use, at Cheshunt, in Hert. vis-à-vis, with a little dickey behind, fordshire, hy Mr. Gibbs, of that place. the whole carriage being covered The line of railway runs from the with an awning.” high road at the lower end of the village, through Mr. Gibbs land, to the river Lea, and is nearly a inile long. It consists of a single elevated line

ELECTRICAL EEL.:. of surface, supported upon vertical A specimen of the gymnotus elecposts of wood, fixed in the ground tricus has lately been examined by in a peculiar mariner, to render their the Parisian suvuns. The greater position secure. These posts are at number were satisfied with a single the distance of about ten feet from touch, and consequent shock; but

288

ANSWERS TO INQUIRIES-CORRESPONDENCE. óne doctor, either urged by a greater

LONDON BRthe zeal for science, or governed by a Sir, I feel oblired for the insertion, more insatiable curiosity, resolved in the 97th Number of your valuable to try the utmost extent of the ani- little work, the Mechanics' Magazine, mal's powers, and seized it with both of my letter of the 13th June, giving his hands, but had quickly reason to my idea as to the plan to be adopted repent his temerity; for he immedi- at the new London Bridge, and which atély felt a rapidlý repeated series of I had oftimes before stated to the publie. the inost violent and successively in

Celiin but without effect. I find that my sug

gestion has now been attended to by creasing shocks, which forced him

the persons concerned in that building, to leap about in the most extraordi- and that a resolution is come to, on nary manner, and to utter the most the part of the City, to make the bridge piercing screams, from the agony four feet wider than the plan at first that he felt. He then fell into con- adopted. This will be a great accomvulsions, in consequence of which modation to the public, although I his muscles became violently con- could have wished it six or seven feet tracted, as, from some strange pro- w

on wider, instead of four. perty in the fish, it became impossi-i

I hear, from good authority, that

the additional expense is estimated at ble to detach the animal from his

25,8001., but surely this cannot be an grasp. In this situation he remained object in a work of such magnitude and a considerable time, and would in bepe it to the nation.

all probability have expired under the agony of bis sensations, if someo A PROMOTER OF IMPROVEMENTS, of the persons had not suggested the East. place, Lambeth, 18th July. plunging of the hands in water, when the eel immediately dropped off. The doctor has since been dangerously ill.

CORRESPONDENCE.

T.M.B. will please to send on Monday USE OF SUGAR AS AN ANTIDOTE TO to our publishers, for the explanation he

LEAD IN CASES OF POISONING: requires.

The following fact has been stated The communications of our friend by M. Reynard to the Société des . H. have been received; one has been Sciences of Lisle. During the cam- inserted, and the others will probably paign of Russia, several loaves of have a place very soon. sugar had been enclosed in a chest

We shall be glad to hear monthly from containing some flasks of extract of

Mr. Lean.. lead. One of these flasks having

A letter has been forwarded to Amicus been broken, the liquid escaped, and

Veritatis, as directed. the sugar became impregnated with Communications have been received it. During the distresses of the cam

from Philo-Montis-W.GxMr. Wm.

Spencer-N. H.-G. R. Mr. Farleypaign it was necessary to have re. A

A. B.-Clio-A Journeyman Carpenter course to this sugar; but far from at Royston-Caasi Llab-E.B. (Skipton) producing the fatal results which - Isaac B.-J. H.-C. N. B. Augustus were expected, the sugar formed a -Henry Jones-F. B. salutary article of nourishment to those who made use of it, and gave

** Advertisements for the Covers of them a degree of vigour and activity

our Monthly Parts must be sent in to which was of the greatest service in our Publishers before the 20th day of enabling them to support the fatigues each Month. of marching. Hence M. Reynard thinks that sugar might be adopted Communications (post paid) to be ndaressed to for preventing the effects of subace- the Editor, at the Publishers’, KNIGHT and tate of lead, instead of the sulphates LACEY, 55, Paternoster-row, London. of soda and of magnesia, which are Printed by Mills, Jowett, and Mills (late not always at hand.

Bensley), Bolt-court, Fleet-street.

Mechanics' Magazine, MUSEUM, REGISTER, JOURNAL, AND GAZETTE.

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" Even though strength should fail, stin boldness shall have its praise ; in great attempts it is enongb to dare."'--Propertius.

.:AN AIR BALLOON,
* INVENTED IN THE SEVENTEENTH CENTURY.

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