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ON THE AURORA BOREALIS AS A
WEATHER PROGNOSTIC.*

BY MR. MURRAY GLADSTONE.
T is upwards of thirty-six years since my
attention was directed to the aurora borealis
as a weather prognostic. I was then residing in
Cheshire, having frequently to cross the river
Mersey, and ride or drive several miles after
dusk, which gave much opportunity of observing
the aurora, and of remarking the nature of the
weather which accompanied and followed its ap-
pearance. I think it was generally seen when the
wind, if any, was light; and in winter inclined to
be northerly, with a tendency to frost; and when
the corruscations were vivid, and particularly if
extending towards the zenith, or showing much
motion, I remarked that the aurora was almost
invariably followed by a gale of wind, with rain,
from S.W.-within from forty-eight hours to four
days. The more brilliant and lively the appearance
and motion of the aurora, the earlier the gale
which followed took place, and the greater was its
severity. Slighter manifestations of the northern
lights were not followed by any appreciable change

of weather.

One of the most striking appearances of the aurora I ever witnessed was at Corrimony, on November 18, 1848. It was of a deep fiery red colour, and extended all over the heavens; even from the zenith down to the summits of the southern hills; and within two days it was succeeded by one of the most violent storms of wind and rain from the S.W., I ever witnessed in that part of the kingdom. I was only within the last four or five years that I met with an extract from a newspaper-published, at the time, in one of the midland counties of England-in which reference was made to the same appearance of the aurora borealis; on the same date, and about the same hour in the evening, eight or nine o'clock. It gave a similar description as to colour, extent over the visible horizon, &c., but added that it was not followed, "as usual," by westerly wind and rain. I would call attention to this fact, as it serves to illustrate a theory I would offer in explanation of the phenomenon generally.

I would only further notice an observation somewhat different in kind, and made during the day; it was mentioned by my grieve, soon after I went to reside in Elen Urquhart, 26 years ago; and he was one of the most observant and intelligent men of his class I ever met with. On a brilliant afternoon towards the end of summer, I happened to remark to him, how very fine the weather had been and was, when, shading his eyes from the sun, and looking up over head, he replied that notwithstanding, there would be rain in three days, "for he saw it in the sky;" adding, he found this almost always right. On inquiry, and looking up in a similar way, I discovered that what he saw was a faint streaky cloud, nearly in the zenith, with a shooting and sort of wavy motion towards its southern margin. This prediction was verified

back to the poles, in the higher regions of the
atmosphere. This general circulation is, no doubt,
much modified nearer the surface of the globe, by
large islands, chains of mountains, and more
especially by extensive continents, as they are
heated or cooled down by the comparative pre-
sence or absence of the sun's rays. But where not
influenced by such cases, and in those latitudes
where they have room to expand and find uninter-
rupted course over a wide and unbroken extent of
ocean, the unvarying direction and perennial
nature of the N.E. and S.E. trade winds appears to
prove the fact of a constant flow of air from the
poles towards the equator. On their approaching
the equator, these winds, as might be anticipated
enter a zone of frequent calms, and are lost. This
constant supply of air, poured from both poles
towards the equator, must find vent in some way;
and while running down the N.E. trade winds on
a voyage to India, I have repeatedly observed,
through the intervals of the lower clouds, detached
thin ones moving at a great elevation towards the
north, and directly against the course of the trade
winds and of the much lower but heavier stratum
of vapour carried along with them.

At the changes of monsoons, the opposite winds
are found charged, respectively, with negative and
positive electricity, and heavy storms of thunder
and lightning result on their meeting; and the
same is observed in a minor degree when easterly
and westerly winds meet. Magnetism, so powerful
in the higher latitudes, is weakened towards the
equator; and if it may be inferred that, in like
manner, the positive electricity brought by the
atmosphere from the poles is discharged on
approaching the equator and becomes negative, an
explanation would be afforded of the cause and
nature of the aurora borealis. This is distinctly
given as his opinion by the late Admiral Fitzroy,
in his report of 1864, on the Polar and Equatorial
Air Currents.*

whole line.

Sir John also speaks of the waving motion being accompanied by a very perceptibly audible sound. This may be aided by the known property of highly condensed air to transmit sound to unusual distances; and I have a strong impression of having myself heard a sound similar to that produced by the waving of a flag, when the aurora was playing actively.

As far as it is known, the identity of the light flickering clouds, above described as seen by day, and of the aurora as visible at night, is a new observation; and the following opinions, expressed by men of great eminence in meteorological science, while in no instance identical with the theory here proposed, may, it appears, be not unfairly adduced in its support. Beccaria, in the last century, offered a suggestion that there was a constant circulation of the electric fluid between north and south; but he gave an explanation different from the foregoing of the manner in which he conceived it might take place. Herschel states his idea, in general terms, that the northern lights are produced by the electric fluid; and Admiral Fitzroy, in his report referred to above, "On the Polar and Equatorial Air Currents," has the following passago:-"We find here that the main currents, polar and equatorial, have very different electrical characteristics-one, the polar being always plus, the other, always minus:-if pure, unmixed with the polar." There is, besides, the well-known experiment of passing an electric spark, in vacuo, through a glass tube, when it presents the appearance of the aurora borealis, even with its play.

I would only further advert to the fact, mentioned above, that the remarkable aurora in November, 1848, was not followed by rain, where seen in England; while within two days after its occurrence, there was a perfect deluge of rain, and almost a hurricane, in Invernesshire. If, on reaching a few degrees further north, the column of air from the south had come into contact with that from the north in sufficient force to drive it back on the surface of the earth; in other words, had proceeded so much farther downwards on its course to its ultimate depression near the pole, as thereby (in consequence of its necessary contact with the colder northern atmosphere) to condense and discharge the vapour with which it was itsel loaded, but which it was too high up to get rid of when seen in the centre of England; if this were the case with that remarkable aurora borealis, may it not likewise, without unfairness, be deemed a corroboration of the theory suggested?

BALLOON OBSERVATIONS.

a communication addressed to the Academy

Ia gives an account

When a larger body than usual of light air from the south begins to descend upon the upper surface of the stream from the north, as those opposite currents in the atmosphere come into close proximity, their negativo and positive electricities produce corruscations. The rarity of the atmosphere and the great elevation probably prevent (at least, for the most part), any sound or thunder being heard; and the former cause, joined with the manner in which the currents approach each other, may probably occasion the shooting, flickering movements of the aurora, and of the clouds formerly mentioned as being seen by day. The arches of boreal light frequently seen stretching from E. to W., may be produced by large masses of air, charged with opposite electricities, meeting each other and feeding the flame, quietly and continuously, on an extended front; while the movements of light occasionally occurring throughout of the phenomena he observed during a late scienthe length of these arches, may arise from the he states that its intensity is propagated to a contific ascent in an air-balloon. As regards sound, masses of vapour coming more actively into considerable height in the atmosphere. Thus, he heard tact at particular points, and lighting up a corruscation, which, like a running fire, passes along the the whistle of a steam-engine at an altitude of in the instance here referred to; and as often, 3,000 metres; the noise of a railway train passing, afterwards, as I happened to remark the same When the corruscations are more than usually at 2,500 metres; the barking of dogs, at 1,800 appearances, but my attention was never so much, vivid, or violent in their motion, it would indicate metres; the report of a gun, the same; the cries nor from its nature, so often directed to this as to a larger arrival than usual of negatively electric of a large crowd, the crowing of cocks, and the the nocturnal phenomenon; and I do not, from my air from S. or S. W., which, in a shorter or longer noise of bells, at 1,600 metres; the sound of drums own experience, speak of it with the same con- time, according to its strength, first checks, and and the music of an orchestra, at 1,400 metres; fidence-but I cannot resist the conclusion that it then overpowers the N. or N.E. wind generally 1,200 metres; the human voice, at 1,000 metres the rumbling of carriages on a stone pavement, at is the same meteor, only presenting a different blowing when the aurora is seen. appearance as seen at night, and in bright sun-perature of the atmosphere, cooled down by the (5-8ths of a mile); the croaking of frogs. 900; light. recent northerly wind, condenses the moisture and the chirping of a cricket, at 800 metres. It is not so in the case of a descending sound; for From the frequency with which the aurora was borne by that from the warm south, and precipiat one time brought before me, I was gradually led tates it in showers; or, in more extreme cases, in the voice of the aeronaut, at an altitude of 100 metres cannot make itself heard distinctly. The to form some theory explanatory of its nature, and storms of rain. If I do not mistake, Sir John Ross clouds offer no impediment to an ascending sound. of the weather changes I had observed to succeed describes the aurora in high northern latitudes, in The average velocity per second in the latter case it, which I here submit, with diffidence, for con- winter, as being frequent, almost constant, as well is about 340 metres. The quiet waters of a lake sideration. I would first notice a remark made, if as very near the earth. The cause of this seems I recollect aright, by Sir John Ross, the Arctic to be the opposing currents being then close to the echo the sound best upwards. While the balloon moves in obedience to the current, its shadow navigator, that the aurora was confined to the point where they must necessarily come into conlower (or lowest) regions of the atmosphere. That tact, and where even the smallest portion remain-sweeps either the earth or the clouds. It is genethis should be the case in very high northern lati-ing of the opposite electricity must be discharged. rally black, but it sometimes happens that, falling upon a darker spot than itself on the country, it tudes, would be quite in accordance with the "We have also found the telegraph wires much assumes rather a luminous appearance. In this theory I have formed. That the reverse is the case disturbed when these main (principal) currents were case, examined through a telescope, it is found to in our own country may be inferred from the ap- beginning to act positively in force. No great tempest-consist of a dark central nucleus surrounded by pearances in Invernesshire, and in England in no heavy polar or tropical gale has occurred here since luminous penumbra. 1860 without more or less wire disturbance' (as the teleNovember, 1848;-and, I believe, from many graphists say); and I am led by these, with other consimilar phenomena being observed, at the same comitant facts, and examination of numerous sea records, times, over wide ranges of the lower latitudes. as well as registers on land, to believe that such electric But this, if correct, is equally in accordance with magnetic storms, sedulously watched now at many effects are caused by atmospheric collision, and that the theory. observatories, are results of atmospheric storms, some where in one hemisphere or other, instantaneously felt through the air, however remote- or by conduction, or by middle of a deep ocean, even the South Pacific." vibration-as an earthquake is felt on board ship in the The Rev. P. Secchi. Director of the Roman observatory. in writing of magnetie currents in a wire in the magnetic meridian, states that disturbances in it indicate the approach of storms as well as the barometer.

In explanation, I will suppose it may be assumed that the air passes from the poles towards the equator; where, being rarefied, it rises, and, in considerable degree, at least, returns

*

Literary and Philosophical Society.

The lower tem

On the green trees of a forest it appears yellow. On the clouds, when they are white, and at the moment of issuing again into the pure sky with the sun shining, the air balloon is minutely depicted with all its details, and of a greyish hue. When it has reached an altitude of 3,000 metres, the sky appears dark and impenetrable, in proportion as there is a diminution of moisture. The light of the rising sun appears to penetrate through every terrestrial object, while that of the moon, which is always red, seems only to glide over them.

!

ON COMBUSTION UNDER PRESSURE.*
BY PROFESSOR FRANKLAND.

THE author commenced by stating that the
HE author commenced by stating that the
from observing the way in which candles burned
at the top of Mont Blanc, and the law deduced
therefrom was that the diminution of illuminating
power was exactly in proportion to the diminution
of atmospheric pressure. The professor stated that
some years ago, while he was on the summit of
Mont Blanc at night, he was struck with the want
of illuminating power in the candles burnt in the
tent in which they stopped for the night. He had
observed similar results in other elevated regions.
The diminution of the illuminating power was, in
all probability, due to the reduction of atmospheric

pressure.

If they took an ordinary gas flame, and placed a piece of paper with writing on it against the flame, looking steadily through it, they would be able to read the writing as well or nearly as well as if the

flame were not there at all.

into contact with a number of flames which emitted

manifestly impossible that this substance should
exist in the solid form at the temperature of the
phosphorus flame, which far transcends the melting
point of platinum.

when exploded in closed glass vessels, so as to
prevent their expansion at the moment of com-

bustion.

It is

temperature in this case is probably greatly inferior to that produced by the combustion of phosphorus in oxygen. We have not all the necessary data for calculating the temperature of these flames, but For these reasons, and for others which the according to Andrews, phosphorus burnt in oxygen speaker had stated in a course of lectures on coal gives 5,747 heat units, which divided by the weight gas, delivered in March, 1867, and printed in the of the product from one gram of phosphorus, gives "Journal of Gas Lighting," he considered that 2,500 units. When phosphorus burns in chlorine, incandescent particles of carbon are not the source it gives only, according to the same authority, of light in gas and candle flames, but that the 2,085 heat units, which, divided as before by the luminosity of these flames is due to radiations from weight of the product, gives 470 units. dense but transparent hydrocarbon vapours. As a therefore evident that the temperature in the latter further generalization from the above-mentioned case must be greatly below that produced in the experiments he was led to the conclusion that dense former, unless the specific heat of phosphoric gases and vapours become luminous at much lower anhydride be enormously higher than that of phoslow specific gravity; and that this result is to a found that if the temperature of the flame of phosThe speaker had, in fact, temperatures than æriform fluids of comparatively phorus trichloride. great extent, if not altogether, independent of the phorus, burning in chlorine, be raised about 500deg. nature of the gas or vapour, inasmuch as he found Cent. by previously heating both elements to that the gases of low density, which are not that extent, the flame emitted a brilliant white luminous at a given temperature when burnt under light. common atmospheric pressure, become so when To return to ordinary luminous flames, the they are simultaneously compressed. Thus, mix-argument of the necessity of solid particles to The commonly-received opinion was that we must have incandescent solid or liquid substances tures of hydrogen and carbonic oxide with hydrogen explain their luminosity obviously falls to the in order to produce a white light in gaseous flames.mit but little light when they are burnt or ground; and a closer examination into the evidence exploded in free air, but exhibit intense luminosity of the existence of these particles reveals its exIn following out this subject he had been brought treme weakness. Soot from a gas flame is not a considerable amount of light, but which did not elementary carbon; it always contains hydrogen. The perfect transparency of the luminous portion contain any solid matter whatever. One was In a communication just made to the Royal of flame also tends to negative the idea of the premetallic arsenic, burnt with oxygen gas. It emitted Society, the speaker had described the extension sence in it of solid particles. The continuous an intense and brilliant white light. Bisulphide of of these experiments to the combustion of jets of spectrum of gas and candle flames does not require, carbon also emitted a very intense light; indeed, so as is commonly supposed, the assumption of solid intense that it had been employed to take instan- hydrogen and carbonic oxide in oxygen under a taneous photographs. This was produced without pressure gradually increasing to twenty atmo- particles. The spectra of the flames of carbonic the possibility of a solid or liquid matter existing spheres. These experiments, which were conducted oxide in air, of carbonic disulphide, arsenic, and in the flame while the light was being evolved. If made in a strong wrought-iron vessel furnished we have seen, is that of hydrogen burning in in the laboratory of the Royal Institution, were phosphorus in oxygen, are continuous, and so, as oxygen and hydrogen were enclosed in a soap with a thick glass plate of sufficient size to permit oxygen under a pressure of ten atmospheres. It is bubble or other light envelope, and exploded, there of the optical examination of the flame. The to the behaviour of hydrocarbons under the inwas scarcely any light produced, but if they were enclosed in a strong vessel and exploded by means appearance of a jet of hydrogen burning in oxygen fluence of heat that we must look for the source under the ordinary atmospheric pressure was of luminosity in a gas flame. These gradually of an electric spark, at the moment of their comexhibited. On increasing the pressure to two lose hydrogen whilst their carbon atoms coalesce bustion the light would have an increased luminosity to the extent of ten times above that in the atmospheres, the previously feeble luminosity was to form compounds of greater complexity, and conshown to be very markedly augmented, whilst at sequently of greater vapour density. Thus marsh previous case. Ignited gas emitted light in pro- ten atmospheres' pressure, the light emitted by a gas, CH4, becomes acetylene, C2 H2, and the portion to its density. The increase of luminosity in flames the professor considered to be due to the jet about one inch long, was amply sufficient to density increases from 8 to 13. Again olefiant gas, enable the observer to read a newspaper at a dis- C 2 H 4, forms napthaline, C10 H presence of dense hydrocarbon vapours. One of the most interesting experiments shown was that tance of two feet from the flame, and this without density augments from 1 to 64. These are some of sending an electric spark first through air under any reflecting surface behind the flame. Examined of the dense hydrocarbons which are known to ordinary pressure, and then through air under by the spectroscope, the spectrum of this flame is exist in a gas flame, but there are doubtless others bright and perfectly continuous from red to violet. still more dense; pitch, for instance, must consist doubled pressure. The result was that the light With a higher initial luminosity the flame of of the condensed vapours of such heavy hydroof the spark due to combustion of the air was very carbonic oxide in oxygen becomes much more carbons, for it distils over from the retorts in tho much increased. The spark was sent also through luminous at a pressure of ten atmospheres than a process of gas making. Candle flames are similarly many other gaseous and vapourized substances, showing most conclusively that the greater the flame of hydrogen of the same size and burning constituted. The direct dependence of the luminosity under the same pressure. The spectrum of car- of gas and candle flames upon atmospheric pressure atomic weight of the bodies the greater was the bonic oxide burning in oxygen under a pressure of also strongly confirms the view that the light of luminosity of their flames when submitted to com- fourteen atmospheres is very brilliant and perfectly these flam s is due to incandescent dense vapours. bustion by the electric spark.

continuous.

dride.

8,

when the vapour

This inquiry cannot be confined to terrestrial objects. Science seeks alike for law in the meanest and grandest objects of creat on. From questioning a candle she addresses herself to suns, stars, nebulæ, and comets; the same considerations which have just been applied to gas and candle flames are equally pertinent to these great cosmical sources of light.

SHAW AND JUSTICE'S PATENT DEAD
STROKE POWER HAMMER. *

The speaker then proceeded to investigate a number of different flames. He showed that there If it be true that dense gases emit more light are many flames possessing a high degree of lumi- than rare ones when ignited, the passage of the nosity which cannot possibly contain solid particles. electric spark through different gases ought to Thus the flame of metallic arsenic burning in produce an amount of light varying with the oxygen emits a remarkably intense white light, density of the gas; and the speaker showed that and as metallic arsenic volatilizes at 180deg. Cent., electric sparks passed as nearly as possible, under and its products of combustion, arsenious anhydride, similar conditions, through hydrogen, oxygen, at 218deg. Cent., whilst the temperature of incan-chlorine, and sulphurous anhydride, emit light, the descence in solids is at least 500deg. Cent., it is intensity of which is very slight in the case of obviously impossible here to assume the presence hydrogen, considerable in that of oxygen, and very of ignited solid particles in the flame. Again, if great in the case of chlorine and sulphurous anhycarbonic disulphide vapour be made to burn in On passing a stream of induction sparks BY MR. JAMES FLETCHER, JUN., OF MANCHESTER. oxygen, or oxygen in carbonic disulphide vapour, through the gas standing over liquefied sulphurous N introducing improved an almost insupportably brilliant light is the result; anhydride in a strong tube at the ordinary tempera-ritor think it would vot power hammer, the now fuliginous matter is never present in any partture, when a pressure of about three atmospheres observe that many and varied attempts have been of this flame, and the boiling point of sulphur was exerted by the gas, a very brilliant light was made at different times to produce a power hamA stream of induction sparks was passed mer that can be driven by a strap from a line shaft; (440deg. Cont.) is below the temperature of incan- obtained. descence, so that the assumption of solid particles through air confined in a glass tube connected with and still possess all the essential qualities of a in the flame is here also inadmissible. If the last a condensing syringe, and the pressure of the air steam hammer, viz., to strike light or heavy blows experiment be varied by the substitution of nitric being then augmented to two or three atmospheres, (one or more at a time), to run quick or slow, to oxide gas for oxygen, the result is still the same; a very marked increase in the luminosity of the be perfectly under control, and capable of being and the dazzling light produced by the combustion sparks was observed, whilst on allowing the con- stopped instantaneously. of these compounds is also so rich in the more re-densed air to escape, the same phenomena were frangible rays that it has been employed in taking observed in the reverse order. instantaneous photographs and for exhibiting the Way's mercurial light was also exhibited as an phenomena of fluorescence. Lastly, amongst the chemical reactions celebrated for the production of dazzling light, there are few which surpass the active combustion of phosphorus in oxygen. Now phosphoric anhydride, the product of this combustion, is volatile at a red heat, † and it is therefore

* Read before the British Association.

Davy mentions this fact in connection with his view of the source of luminosity in flames, and endeavours to explain the (to him) anomalous phenomenon. He says:"Since this paper has been written, I have found that phosphoric acid volatilizes slowly at a strong red heat, but under moderate pressure it bears a white heat, and in a flame so intense as that of phosphorus the elastic force must produce the effect of compression."-"Davy's Works," vol. vi., p. 48.

instance of intense light produced by the ignition
of the heavy vapour of mercury.

The gas and vapours just mentioned have the
following relative densities:- Hydrogen, 1; air,
145; oxygen, 16; sulphurous anhydride, 32;
chlorine, 355; mercury, 100; phosphoric anhy-
dride, 71 or 142.

The oldest form of power hammers, the helve and tilt, have proved themselves, and are still considered, extremely useful for a variety of purposes, especially for shingling, forging blooms, round shafting, railway axles, and tilting steel; but as their speed, or weight of blow, cannot be altered, they are ill adapted for heavy forgings, or general smithwork, and consequently for these purposes have been superseded by the steam hammer. Many spring and atmospheric hammers have been made mostly with a cam motion to compress the spring or air contained in the cylinder, but as these arrangements absorbed a great amount of power, the steam hammer being much more manageable, and having as few or less working parts to get out of order, has been used in preference, even when it

The feeble light emitted by phosphorus when burning in chlorine seems, at first sight, to be an exception to the law just indicated, for the density of the product of combustion (phosphorus trichloride) 68-7, would lead us to anticipate the evolution of considerable light. But it must be borne in mind that the luminosity of a flame depends also upon its temperature, and it can be shown that the * Read before the Manchester Institution of Engineers.

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has been necessary to place it in a very inconvenient locality, on account of being near a boiler. The hammer of which the writer is about to give a description is the invention of Messrs. Shaw and Justice, of Philadelphia, and is one of those peculiar and simple inventions, so many of which have emanated from our cousins across the Atlantic. Its principal feature is the application of a semicircular spring between the crank pin and the tup or upper moving hammer, to which it is attached by a leather band. Diagrams 1 and 2 are front and side elevations of the hammer. A is the driving pulley, driven from any line or countershaft most convenient; B is the shaft; C is a circular friction disc, or plate of iron truly turned on its face, and supported by brackets projecting from the main casting of the hammer; D is a friction pulley covered with leather, upon which the disc C is pressed when the hammer is in action; E is the shaft carrying the fly crank wheel F, and also revolves in bearings cast in the main frame; G is the crank pin, which raises and lowers the tup; H is a connecting rod made in two parts, and capable of being lengthened and shortened by means of the tube I and set screw K. The lower part of the connecting rod H is attached to the spring by means of the cramp plate L, and two bolts which grip the centre or thickest part of the spring M. This spring is of semicircular form, and consists of a number of steel plates put together in the same manner as a coach spring. The ends of the outside or upper plate, projecting a little below the other plates of the spring, are formed in the shape of a hook, and fitted with brass bushes N, through which the pin O passes, connecting the links P to the brass bushes Q, round which the strap R is stretched.

The tup S is composed of Bessemer steel, having a slot in the upper end, through which the leather band R passes. In the bottom there is a dovetailed slot, so that different shapes or forms of swages or dies may be introduced. The anvil block T is keyed in a groove planed in the main frame, the bottom or front part of which is cast solid, forming an anvil block to resist the action of the hammer. The levers W X (the latter having brass clips at the upper ends working in a groove turned in the boss of the friction pulley D) are for the purpose of bringing it nearer or further from the centre of the friction disc C, so as to alter the maximum speed of the hammer. The lever

W is provided with a quadrant and lock handle Y to fix it in any desired position.

A A is a lever for starting, stopping, or varying the speed, and has a cam B B forged upon its boss which, when the lever A A is depresse d, raises the brake C C against the fly-wheel F. This lever is keyed on the shaft D D which passes through the frame, and has on its other end a cam EE, which is for the purpose of raising or lowering the lever F F and weight G G, which is fixed upon the stud H H, having a steel tail pin on a joint at its upper end, and is for the purpose of pressing the friction disc C against the friction pulley D. The two cams being keyed on the shaft DD are simultaneous in their action. Thus, when the lever A A is raised the cam B B relieves the brake C C from the fly-wheel F; at the same time the cam E E lets the lever F F and weight G G down, the tail-pin pressing upon the hardened steel end of the shaft B, thus putting the hammer in motion by the contact of the friction wheels; and when the lever A A is depressed the cam B B puts on the brake, whilst the cam E E raises the lever F F and the weight G G, and releases the pressure from the friction disc or pulleys, allowing the brake to arrest the motion of the hammer instantaneously when in any position. The cam EE is made flat on its upper end, as shown on diagram 1, fig. 2, so that the action of the lever F F and weight G G holds the lever A A up when the hammer is not in action, and dispenses with a quadrant and catch or other fastenings. By only partially raising the lever A A the weight upon the friction disc can be regulated so as to run at any speed required or give the requisite weight of blow."

Another method of varying the speed and blow has been extensively used in America with much success. In this case it is necessary that the driving pulley should be immediately over that on the hammer, making it sometimes necessary to employ a countershaft. The pulley is made with a flange on each side to prevent the strap, which is left so long and slack that when the hammer is not in motion it runs loosely between the flanges without touching the body of the pulley. The same brake motion and stopping and starting lever are employed as previously described, but instead of friction pulleys and the weight, lever, and cam motion a lever is fixed on the back of the frame, carrying a guide or pressure pulley. When the

lever is lowered it relieves the cam from the brake and presses the pulley against the strap, thus tightening it upon the driving pulley and setting the hammer in motion, the pressure put upon the strap by the pulley regulating the speed of the hammer by allowing the strap to slip when running slowly, and tightening it as the speed is to be increased.

The writer will now draw your attention to the principal features of this hammer, namely, the action of the spring. When the hammer is at rest, and the crank pin on the bottom centre, it will be observed from the model and diagrams 1 and 2 exhibited, that the face of the upper hammer does not touch the anvil block. In the model, the tup of which is only 2lb. weight, there is a clear space of nearly gin., and in one of 14cwt. there is 3in. to 3in. When the hammer is running the moment the crank pin passes the bottom centre it plucks or snatches at the tup through the spring and leather band, but the tup being in a state of rest cannot necessarily be so suddenly raised as it would were it directly attached by a connecting rod to the crank pin; but the spring giving way, as will be understood, it moves slowly at first, and gradually increases its upward speed by the combined action of the spring and crank pin, the former of which is endeavouring to stretch or pull the leather band in a straight line. By the time the crank pin has arrived at the top centre the spring has extended itself, but the tup having gathered so much impetus declines to stop, and still going upwards it is met by the downward action of the crank pin, which again collapses the spring, when the tup, assisted by the spring, crank pin, and its own weight, comes down with great force. The tup, when going at full speed, traverses about double the throw of the crank. In consequence of the spring being placed between the crank pin and the hammer the weight comes gently upon the crank pin, causing very little strain. The connecting rod H being in two parts, through which all the strain passes, is held together by only one steel screw. The weight of the blow is entirely dependent upon the speed at which the hammer runs, striking a light blow when running slowly and a heavy one when running quickly.

This hammer possesses a great many advantages over all others. It can be fixed in any desired situation wherever there is a driving shaft, and is

independent of boilers. It takes less power than any other hammer. The writer has no doubt that the same amount of steam which it takes to work a steam hammer would drive, by means of an engine, at least three of these hammers, each doing the same amount of work. It has very few working parts, is not at all liable to get out of order, and the cost in repairs is merely nominal. There are no cylinder, valve rods, or joints; no packing required, or any attention after working hours; the bearings are brass, and made very long. It is so simple to work and easy to control that no instructions are necessary, and any boy in the smithy can manage it. It is self-contained, and requires but little foundation. For tilting steel it will be found an excellent substitute for ordinary tilt hammers with wooden shafts, which are constantly breaking. In this case it may be further simplified by being driven by a pair of cone pulleys, and thrown out of gear by means of a clutch box or friction clutch. By driving it this way, the speed can be varied according to the size of steel required to be tilted, and the hammer would run at a regular speed. The diagrams 1 and 2 represent a 1cwt. hammer which the writer has had at work for some

time with the most gratifying results. It is quite adequate to work 4in. steel, round or square, and its maximum speed is 200 blows per minute.

THE DUTCH MONITOR "DE STIER."

WE

E have from time to time noticed in our columns the several ironclad rams and monitors which

the Dutch Government has been building in this country for the defence of their coasts and harbours. The last of these, "De Stier," has just been completed by Messrs. Laird Brothers, at Birkenhead.

Her

Captain Hugenholtz, of the Dutch Royal Navy, who
has come round in the "Buffel," another armour-plated
turret vessel, with the officers and crew, to navigate
the "Stier" to Holland, Lieutenant Bogearts being in
Stier" outside the harbour to try the guns, slides, &c.,
charge. Afterwards, Captain Hugenholtz took the
and the turret gear, all of which were in charge of,
and worked by, the officers and crew of the ship, and
several rounds were fired, first from each gun singly,
and afterwards both guns simultaneously, they being
loaded with the full charge of 431b. of powder, and
filled shell weighing 300lb. The turret was worked
entirely by the steam gear whilst the firing was
going on, and it was found thoroughly under control,
a complete revolution being made in thirty-five
seconds; and all the gun gear worked very satis-
factorily. Captain C. P. Coles, R.N., C.B., was on
the arrangements of the ship. After the trial of her
board, and expressed himself well pleased with all
guns, the "Stier" returned to Birkenhead dock to
complete her coaling, &c., and will leave for Holland
in a few days.

The more we see of these Dutch monitors the more
convinced are we that sooner or later our Govern-
ment will be compelled to adopt similar ones for
coast defence purposes in preference to forts. They
are small and difficult to hit, require few men, are
of time are able to concentrate on any given point a
easily manoeuvred, and in the briefest possible space
most destructive fire, remaining themselves nearly
impervious to shot and shell. The gunners in the
turrets suffer no inconvenience whatever from the
explosion, and what little smoke there is rapidly
clears off through the gratings. Such a vessel as the
"De Stier" might, despite our forts, steam up the
Mersey, and with impunity do millions worth of
damage in a very short time." Liverpool Albion."

A NOVEL RAILWAY.

Wash

current.

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CRYSTAL PALACE SPECIAL EXHIBITION. HE laudable intention of the managers of the THE Crystal Palace in arranging these exhibitions only from no shortcoming on their part. The inhas been only partially carried out, but partially tention was to afford space for a display of the articles-English products, manufactures, and others-which had been exhibited at the Paris Exposition of last year. The chief difficulty in carrying out this intention has arisen from the fact that the articles exhibited, and especially those which took prizes, have been disposed of, and the owners are indisposed to incur the trouble and cost of producing duplicates. The series of exhibitions, notwithstanding this hindrance, has been be expected to be very attractive, if well supplied very interesting, and the two that still remain may by exhibitors. The first of these, which commences on the 26th current, will include agricultural, chemical, and farinaceous products; perfumery, condiments, vegetables, and fruits. The exhibition following, which will be the last of the series, ought to be the best, including, as it promises to do, apparatus connected with heating agriculture, chemistry, mining and metallurgy, civil engineerand lighting, sewing, telegraphy, ing, and "machines and apparatus in general "very wide designation. The exhibition now on foot is of "portable weapons," and, although the exhibitors are not numerous, is interesting in the variety of breech-loading rifles exhibited. A single firm, Messrs. E. M. Reilly and Co., show almost adopted by the English Government, the French every variety known, including the Snider patent Chassepot, the Belgian Albini, the Austrian Sedehl, the patents of Reeves, Sharp, Prince, dimensions are as follows:-Length, 205ft.; breadth, A Raton, t.. is the summit of Mount Wishley Richards, Green Brothers, Spencer Repeater, RAILWAY to the summit of Restell, Terry, Gilby, Mont Storm, Grainger, West38ft.; depth 19ft.; tonnage, 1,326 tons. She is The station at the starting point is 2,700ft. above the Fosbery, and others. There are also specimens of armour-plated with 6in. plates from 3ft. below the level of the sea, and the road when complete will be the revolving breech, self-capping, and circularwater-line up to the gunwale, for the greater part of two miles and 260 rods long, rising in that distance hammer breech-loaders, of the Reilly-Comblain her length, the plates tapering slightly towards the 3,600ft. to the Tip-Top-house, which is 6,300ft. an improvement on the rifles of the various ends. The armour rests on a backing of 10in. teak, above the level of the sea. and this again on an inner skin of lin. supported by track is 1,280ft. to the mile, but in some parts of the elephants, tigers, deer, wild fowl, rooks, and rabThe average grade of the governments-and of rifles and guns for shooting the framing of the ship. Her turret, which is cylin-line the grade is increased to 1,760ft. to the mile, or bits; with air guns, walking-stick guns, revolvers, drical, and constructed on Captain Cowper Coles' one foot in every three. On this portion of the road, and divers other instruments for offence and deprinciple, is protected all round by armour-plating, workmen, notwithstanding the sharp spikes in their which in no place is in thickness less than 8in., in- shoes to prevent them from falling, could only build fence. This exhibition remains open till the 23rd creased to 11in. round the ports, the plates resting 25ft. per day. The track consists of three raits, the upon a teak backing of 13 inches, with an inner iron one in the middle being of wrought iron, with cogs skin of lin. The turret carries two 300-pounder rifle or pins corresponding to cogs in the driving wheel. COMPOUND ENGINE AT THE LONDON guns, having a range of fire from 10deg. of the line The train consists of the locomotive with a tender of keel forward and 6deg. aft, so that she can in and one passenger car. The locomotive of 35-horse JUTE WORKS. rapid succession deliver her fire at almost all points; power is built with its boiler suspended, so that it is HE engine which forms the subject of our while the facility with which her twin screws enable always level; it weighs four tons, and pushes up the her to turn will make her very handy in action. Her train before it. The driving wheel is 18in. in dia- points worthy of notice. large engravings this week presents many port sills are arranged at a height of 6ft. 6in. above meter. There is a similar cog wheel on the tender, Canal Basin Foundry Company, Glasgow, for the It was made by the water. The turret, in addition to the usual apparatus and another on the passenger car, each strong for working by hand, is fitted with steam gear, which enough to hold the entire train. Friction rollers, London Jute Company, Ponder's End. is under the control of the captain of the turret, the running under the edges of the middle rail, hold the gine, taken as a whole, has four cylinders, or, starting gear being led up to the sighting platform. train down upon the track. The central rail pro- more strictly speaking, will have fou when comOn the main deck is a shot-proof pilot tower, and a jects about lin. on each side beyond the beam on pleted, two being found sufficient for the prepoop and forecastle fitted with supplementary cabins, which it is laid. To the locomotive there are attached sent to drive the mill, although the complete bedin addition to excellent accommodation for officers and one steam brake and one hand brake, either of which plate has been put down. crew below the main deck, under the protection of can stop the train in a moment, and, in ascending, a As the engines are the armour. By the arrangement of hatchways, strong wrought-iron dog works into the cogs of the will suffice to speak of a single pair of cylinders exact duplicates of each other in every respect, it which are carried above the main deck, excellent driving wheel to prevent "back sliding." In descendlight and ventilation for the below-deck cabins are ing, the steam is shut off, and the engine is eased secured; and ample accommodation is reserved below down by using compressed air. An experimental Each engine consists, then, of a high and lowthe water-line for magazines, store-rooms, coal-trip was recently made on the part of the road already pressure cylinder; the diameter of the former is bunkers, &c. The ram-stem is of iron and of great completed, and the locomotive is described as work- 24in., of the latter 36in., the stroke of both being strength, projecting about five feet at such a depth ing with a steady motion. There was no jarring or 5ft. The cylinders, throttle-valve chest, and under the water as to enable her to strike an enemy's rocking, but merely a slight trembling, like that of jackets, are cast in one piece, and, from personal ship below her armour-plating. This formidable a steamer under the stroke of its engines. The inspection, we can pronounce them a thoroughly weapon of offence is built solid into her framework, good job. The cylinder covers are also jacketed, and is so constructed as to resist the shock of the all the spaces being supplied with steam direct collision. Her machinery, which has been made at from the boiler by a distinct pipe. There is but the same works, consists of two pairs of surface-condensing direct-acting engines, each of 175-horse forked at the tail so as to grasp the crosshead as one connecting rod for each pair of pistons, widely power, giving 350-horse power collectively, and are so arranged as to work to a very high indicated near the rods as possible, in order to avoid the power, each pair of engines driving a screw under chance of side strain. The valve chests are arthe counter of about 12ft. diameter. Her boilers are ranged on the upper sides of the cylinders, and the fitted with super-heaters, and the machinery generally valves driven by a single eccentric through the is made in accordance with the new Admiralty spemedium of a rocking shaft, as will be seen at a cifications for engines of this class. The "Stier" made for princiher official trial trip about ten days since, the Dutch Messrs. Merry weather and Sons, of London, a me- pally takes place in a horizontal enlargement of Government being represented by Mr. H. G. Jansen. dium size steamfire-engine, of the same pattern as the waste pipe on its way to the air pump, the The vessel was complete in every respect, having her guns and ammunition and full amount of coals the "L'Imperatrice," one of the engines for which injection water entering just at the elbow and and stores on board; her mean draft of water was this firm was awarded the first prize and gold flowing with the uncondensed vapour to the con15ft. 0 in., the displacement on this draft being 2,025 medal at the Paris Exhibition of last year, with a denser, which is not immersed in a tank. Tho tons. The speed was tested at the measured mile large quantity of hose and reels, so as to enable air pump is actuated by a rocking shaft beneath at the entrance to the Mersey, and six runs at full- the engine to draw water from the river. The the floor of the engine-room; an arm from this boiler power gave a mean speed of 12-458 knots, the engine has a horizontal steam cylinder 8in. dia- shaft also drives the feed pump. The remaining engines making 92 revolutions, and the indicated meter, with 18in. stroke of pistons. It was re- details will be easily gathered from our engraving. horse power being 2,257. Two runs at half boiler power gave a mean speed of 10-778 knots, with 77 cently tried in the presence of the engineer of the We may state that the fly-wheel drives the mill revolutions and 1,234 indicated H.P. The turning Steam of 100lb. pressure was raised from cold lying about the same level as the crank shaft outand gave very satisfactory results. through the medium of a spur wheel on a shaft powers of the vessel were then tried, and she was found to make a complete circle, at full speed, in 44 water in nine minutes, the engines playing a side the wall of the engine-room, through an aperminutes, the diameter of the circle being very small; 14in. stream 170ft. high, and two in. streams the ture in which the spur wheel comes. the rudder, which is fitted on the balance principle, same height, and a 1ğin. stream 160ft. high. The have omitted the wheel in our engraving from can be put hard over at full speed by three men. steam pressure was easily maintained with the want of space. The engine runs at a speed of 400ft. Since this trial the "Stier" has been handed over to fire-door open. per minute.

ascent from the starting point to the second station,
5,500ft. above the level of the sea, was accomplished
in 1 hour and 20 minutes, including two stoppages for
water. The descent occupied 38 minutes. A passen-
ger car holding fifty persons now runs up to the
second station.

STEAM FIRE-ENGINE FOR BUENOS

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HE Western Railway Company of Buenos

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HORIZONTAL COMBINED ENGINE AT THE LONDON

JUTE WORKS, PONDERS END.

THE CANAL BASIN FOUNDRY COMPANY, GLASGOW, ENGINEERS.

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At the first glance it might be assumed that, owing to the arrangement of the cylinders, an injurious twisting strain would be brought on the crossheads, but this is not the case. Steam from the small cylinder exhausts directly into the valvebox of the large cylinder by the shortest possible route; and although the pressure in the small cylinder is much higher than in the large cylinder,

it must be borne in mind, first, that a back pres-
sure equal to the positive pressure on the large
piston has to be deducted from the strain on the
small piston end of the crosshead, while the much
larger area of the low-pressure piston tends still
further to bring about an equality. If steam is
cut off at about one-third of the stroke of the
high-pressure piston the strain is about the same

at each end of the crosshead. It is quite certain that no cvilence of twisting strain is perceptible while the engine is in motion, and engines similar in every respect have been running for five years without requiring one farthing of outlay for repair. It is difficult to see by what other arrangement of compound engine as much power can be provided in a limited space and at a moderate cost,

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