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feeble light. The movement of the air past the flame is also well shown. The ascending current drags the flame out to a pointed figure, and, whilst rushing past the candle, keeps the outside of the cup containing the melted wax or tallow cool. The air that rushes by so quickly burns up the carbon and hydrogen of the outer part of the flame, but does not affect so materially the next structure, where the hydrogen is chiefly burnt and the carbon deposited. Here the flame is the brightest, because of the ignition of the precipitated carbon, and hence the reason that the shadow of this portion should appear so dark. In the inner layer the unburned gas is found waiting its turn to pass to the exterior, to go through the phases of partial combustion and precipitation of the carbon, ending with complete combustion at the exterior. That the interior of a candle flame does consist of unburnt gas may be shown by placing a narrow glass tube in the inner cone of the flame. The tube must be inclined, and if nicely managed the hot gas passing upwards may be inflamed at the top. The same fact is shown by holding a slip of card across the flame. The interior of the cone does not scorch the card, which is blacked at the two points or opposite sides of the centre. The tube may be adjusted so as to draw away the finelydivided carbon deposited in the luminous portion of the flame, and if this is conducted into a separate small hydrogen flame, the latter.becomes luminous in consequence of the incandescence of the carbon derived from the candle. A hydrogen flame affords little or no light, but if a small bit of tow, saturated with benzole or ether, is placed in the bottle containing the materials for generating hydrogen, and the tube or jet fitted into the neck of the bottle, on lighting the hydrogen it is now very luminous, in consequence of the carbon, the solid matter derived from the benzole or ether, being precipitated, ignited, and burnt. To distinguish the bright from the almost unluminous part of the flame, the latter is sometimes called the mantle, because it is the outermost cone. The best method of showing the structure of flame is to place some ether in a tin dish.three inches in diameter and half an inch high. On setting fire to the ether a very large flame is produced, and into its centre may be introduced a cup containing phosphorus, which only sublimes, but does not burn. By very careful manipulation, and when the air is still and not disturbed by open doors or windows, gunpowder may be dropped down a tube held across the hot stratum, and will fall unburnt into a porcelain or other cup, placed in the centre of the flame. A very few grains of powder should be used until the operator has sufficient confidence to perform the experiment steadily. The structure of flame being understood, it is easy to see how the illuminating power of an ordinary flame may be increased by admitting the right proportion of air to the interior. The argand burner furnishes the best illustration of this wellknown principle: if the central tube is corked and the chimney removed, the flame is smoky and unsteady; on replacing the chimney, the current of air rushes with increased velocity past the exterior, and more light is obtained; but the maximum of light is only procured when the cork is removed, and air allowed to pass to the interior as well as the exterior of the flame. When the supply of air is too great, the luminosity of the argand burner is seriously affected, especially if the gas is not rich in hydro-carbons, because the carbon is burnt up at once, and no time is allowed for its precipitation; hence it is now usual to adjust the central or internal tube of the argand burner to the quality of the gas. The diameter of the internal aperture should be less than half an inch—viz., 0.42 of an inch for elevencandle gas, and half an inch for fifteen-candle gas, if used with a glass chimney seven inches long, and burning at the rate of five feet an hour. If coal-gas is mixed with a considerable quantity of air before it is burnt, as in a smokeless burner, or the gauze-burner, the flame is no longer brilliant, because the carbon is burnt with the hydrogen. When the combustible oil, such as turpentine or camphine, contains a very large proportion of carbon, the chimneys are increased in length, and have a peculiar construction, because more air must be supplied to burn the excess of carbon, and to prevent the skame smoking. The Bade light consists of a small argand lamp, burning colza oil; and instead of supplying air to the interior tube, a jet,

is attached; the smoky flame immediately burns most brilliantly, and if the wick is very thick and the oil good, it will afford a considerable amount of light. It is a curious fact that when the pressure of the air is re. duced the luminosity of a burning candle is materially affected. Messrs. Tyndall and Frankland burnt some candles on the summit of Mont Blanc, and although just as much stearine was consumed at that altitude in a given time as at Chamouni, the aspect of the flames was completely altered. They seemed, to use their language, to be the mere ghosts of the flames “which the same candles were competent to produce—pale, feeble, and suggesting a greatly diminished energy of combustion.” The cause of the diminution of the light is not due to any reduction of the rate of burning, but to a more perfect diffusive effect; the oxygen of the air penetrates the flame more perfectly, and the matter of the flame passes more rapidly into the air; and thus, by the mutual interpenetration of the one into the other, the carbon is more rapidly burnt out. Dr. Frankland also discovered the interesting fact, that by compressing the air round the flame of alcohol, which burns with a smokeless flame, it became as bright as coal gas, and at a higher pressure could even be made to smoke. The intensity of any given flameis reduced 5 per cent. for every fall of one inch in the barometer, or increased in the same proportion with each rise of one inch. Dr. Frankland has also shown that the comparative cost of light equal to that obtained from twenty sperm candles, each burning ten hours at the rate of 120 grains per hour, would be as follows:—Wax, 7s. 24.d.; spermaceti, 6s. 8d.; tallow, 2s. 8d.: sperm oil, 1s. 10d. ; coal gas, 44d. ; cannel gas, 3d.; paraffin candles, 3s. 10d. ; paraffin oil, 6d. ; rock oil, 7}d. Consequently paraffin and rock oils are the best sources of light for domestic purposes. They are the cheapest, give the greatest amount of light, and, what is of still greater importance, they do this with the least development of heat. The extraordinary light-giving agents, with the exception of the combustion of magnesium in air or of phosphorus in oxygen, require more elaborate apparatus than the beginner in science is likely to be able to afford. The oxy-calcium light is one of the most simple, and is obtained by forcing a jet of oxygen through

ball of lime. photographs on a small screen in a moderate-sized apartment.

If a more brilliant light is required, the lime or oxy-hydrogen light may be used. It is, of course, easy to place two volumes of hydrogen and one of oxygen in a large bladder furnished with a stop-cock, and then to burn the mixed gases from a Hem. ming's jet. This is undoubtedly the cheapest, but not the safest method, especially if the bladder is squeezed by the hands. A steady pressure is absolutely necessary, and this can only be obtained by using pressure boards. Indeed, it is far better not to attempt either the oxy-calcium or the oxy-hydrogen lights without proper caoutchouc bags, pressure boards, and jets, all of which may now be obtained at a very moderate price of the instrument-makers. The cost of an accident to person of property by the explosion of a large bladder full of the mixed gases in a dwelling-room is very likely to be greater than the purchase of the proper appliances.

Although the electric light is the most brilliant artificial light that can be procured, it is only effective on a proper scale. A . battery on Grove's principle, of forty cells and a good electri

arrangement is continually flickering, and the constant move ment of the charcoal points become tiresome, and fatigues the

again, a good apparatus is the cheapest in the end. The magneto-electric machine will also give a continuous and brilliant electric light, but as the armature must revolve many

used only by a rich body such as the Trinity House brethren. who have employed Professor Holmes' magneto-electric light for many years at the North Foreland lighthouse. The lighted candle in the cottage window has guided many a weary husband over fell and moor to his home, but this magneto. electric light is so large in amount that, with proper optio arrangements, such as Fresnel's lamp, it will flash its friendly rays twenty-five miles across the ocean, and almost rival

conveying oxygen gas from a bladder or small india-rubber bag,

“Those gold candles fix'd in heaven's air.”

the flame of a spirit-lamp, and directing the resulting fire onto a | This light will do very nicely for the exhibition of

lamp, will give excellent results, whilst a smaller

eyes of those who may be invited to see the experiments. Here,

hundred fimes in a minute, and can only be worked effectively with the aid of a steam-engine, such a light is a luxury to be

ELECTRICITY.-III.

the conductor to the knuckle or any other body held to it; or

if bent wires with balls at the end be inserted in the two conCYLINDER ELECTRICAL MACHINE-PLATE MACHINE-ARM

ductors, as shown at D and E, a series of sparks will pass between STRONG'S HYDRO-ELECTRIC MACHINE.

them. It is necessary, if positive electricity is to be used, that It is now time for us to pass on to consider the mode in which the rubber should be connected with the ground, and this is we can obtain electricity in large quantities. This is done by usually done by means of a chain or a piece of wire. In the means of an eleetrical machine, which consists essentially of three same way, if negative electricity is required, the conductor must parts: firstly, the substance to be rubbed, usually a cylinder or be uninsulated. sheet of glass ; secondly, the rubber; and, lastly, the con. As we hope that a great many of our readers will set to work ductor or reservoir to hold the electricity.

and make one of these machines for themselves, we will give Originally a globe of sulphur was employed as the substance rather fuller instructions as to the mode of proceeding. Be to be rubbed, but it was soon discovered that a globe of glass I assured of one thing at starting, and that is that you can easily would answer better, and this

succeed if you only persevere, was accordingly substituted.

B

and are not disheartened by At present, however, a cylin

apparent failure at first. der is usually employed (Fig.

We should recommend you 6). These are made specially

to procure a proper cylinder for the purpose, and can be

if possible; one nine or ten obtained for a moderate

inches long by six or seven amount at glass-works, or

inches in diameter is a very at philosophical instrument

good size, and should not cost makers'. In shape they resem

more than about five shillings; ble a square-shouldered bottle

considerable power may even with a neck at each end. Caps

be obtained from a smaller are turned out of some hard

one. Failing this, a large round

M

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wood to receive these, and should be so shaped that their ends / bottle will answer, but not so well, nor is it nearly so conmay serve as bearings for the cylinder. The winch is fixed to venient. Some people recommend, when a bottle is used, that the squared end of one of the caps.

a hole should be punched through the bottom, but there is conAt one side of the cylinder is placed the rubber, c, which siderable difficulty and risk in doing this. The better plan is to consists of a cushion of wash-leather stuffed with horse-hair or procure a disc of wood a little larger than the bottom of tho tow, and a piece of black silk (not represented in the figure) bottle, and

fix it on by means

of electrical cement. This passes from the under side of this over the cylinder nearly to cement is used for many purposes, and may be easily made. the points on the other side. A conductor, A, is sometimes fired It consists of resin, plaster of Paris, bees’-wax, oil, and red behind the rubber, and serves to collect the negative electricity. lead. The resin is first melted in an earthen pipkin, a small On the other side of the cylinder is the prime conductor, B, lump of bees'-wax and a little oil being added to render it more with a row of points along one side to receive the electricity tough. When fully melted, the

plaster is stirred well in, Holes are bored at different parts of this, in order that brass together with some red lead, to impart a better colour to it. balls and rods or other pieces of apparatus may be inserted The bottle and disc of wood should

then be well warmed, and

the

cement poured upon the former, and if the disc be kept from On turning the cylinder, if the machine has been carefully slipping until it gets cold, the cement will hold firmly. The warmed and dried, and a little amalgam spread upon the larger the proportion of plaster used the harder will be the rubber, vivid sparks, several inches in length, will pass from cement. The winch is put on an axle affixed to this disc, and

92

when required.

VOL. IY

a plug of wood inserted in the mouth of the bottle serves for room, flashes of blue light, accompanied by the peculiar smell a bearing at the other end.

of electricity, and by a faint crackling noise, will be observed When a cylinder is used, caps should be turned of mahogany, passing round the cylinder and issuing from the edge of the or some hard wood, so as to fit loosely on the ends of the cylinder; silk flap. Now bring the conductor so that the points of the these are then fixed on by the cement above referred to, and fork may nearly touch the cylinder, the electricity will then be great care must be taken to ensure the cylinder being mounted collected, and sparks several inches in length may be obtained so as to run perfectly true. If the framework of the machine by holding the knuckle or any conducting substance near it. be made first, it can be put in before the cement is fully set, and If the rubber were insulated, similar sparks might be drawn carefully watched while it is being turned round; it must not, from it, but they would be of negative electricity. The great however, be left in its bearings to set. As the machine is usually point to be remembered in using all electrical apparatus is to warmed before use, an aperture must be left for the escape of have every part of it perfectly dry and free from dust. the air; a hole is therefore drilled through the cap at the ond This form of machine is by far the most common. In it, 19 away from the winch, and, while the cement is being poured we have seen, friction is the exciting cause; hence the power will into the cap, this is filled by a greased wire, which may be be found to depend upon the extent of rubbing surface. With removed as soon as the cement becomes hard,

a view to increase this, two rubbers opposite to one another A better plan of mounting the cylinder has, however, lately have sometimes been affixed to the same machine, and two conbeen tried. The inside is first rendered perfectly clean, and ductors placed between them ; this, however, adds so greatly to then thoroughly dried by exhausting the air, and allowing a fresh the complication of the machine, that the plan is nearly dissupply to enter through a drying tube. When it is thus pre-carded. pared, the caps are put on so as hermetically to seal it. The sur If we remove the chain or wire connecting the rubber with face of the cylinder is rubbed before nse with a rag wetted with the ground, and place one so as to make a communication turpentine, so as to remove all grease, lumps of amalgam, etc., and between the rubber and conductor, we shall find that no spark it is then polished with prepared chalk. This imparts a greatly can be obtained from either, showing that the quantities of increased power to the machine, for sparks of a much greater positive and negative electricity are exactly equal, and therefore length can be in this way obtained, and there is little need of neutralise each other. warming the cylinder before use. Another advantage is that Though the cylinder machine is that most generally used, its the damp does not condense so readily upon it, and thus place is sometimes taken by the plate machine (Fig. 7), especially it can be used at a lecture-table or in a room filled with when great size and power are required. By some this form is prepeople.

ferred as being more compact and ornamental, and the power is The frame-work of the machine can easily be made. It should usually supposed to be about equal for an equal rubbing sur be formed of thoroughly dry wood, baked for a little time; and face; but when the cylinder is mounted on the plan mentioned in making it, great care must be taken to avoid all points and above, the advantage in point of power is on its side. sharp edges which draw off much of the electricity. The support A plate of thick glass has its edges carefully smoothed and at the winch end should be made with a cap, so that the cylinder a hole drilled through its centre for the axle to pass through. may be removed when necessary, and the under side of the This is made of brass, with flanges to press against each side cylinder should be five or six inches above the board.

of the plate and hold it firmly; but as brass is a conductor of It is simpler, too, to make the rubber in a way rather different electricity, a part of the winch is usually made of glass, to from that shown in the figure. As it is not often required to prevent the electricity being conducted away. Two rubbers, obtain negative electricity, the support may be of baked wood, F, F, are employed in the machine, and they are made double, so and the whole should then be shaped like the letter T, the as to grip the plate between them, and thus cause friction on lower end being hinged to the edge of the board, and a hole each side of it." Quadrants of silk are also affixed to the rabber made about two inches up, through which a thumb-screw may to prevent the escape of the electricity before it reaches the pass into a wooden block placed a little way from it, so that conductor, just as a flap of silk was used for the same purpose by means of the screw the rubber may be pressed firmly against in the cylinder machine, and the power will be much augmented the cylinder. Care should be taken in the construction of the if this be covered with varnish. The main disadvantage in this rubber, as much of the power of the machine depends upon it. machine is the difficulty of insulating the rubber so as to draw It should be about one and a half inches wide, and rather negative electricity from it. shorter than the cylinder. Wash-leather answers well for its The conductor is sometimes made in two pieces, as shown at covering, and the horse-hair or tow in it should be so arranged C, c, and the further ends are then connected by a brass rod, but as to give a uniform pressure. The silk flap is fixed to the more frequently it is semicircular, and supported by a single glass under side, and passes up in front of the rubber. At the back upright. The fork should be bent round so as to collect the is a small hook, to which a piece of chain may be attached, and electricity from both sides of the plate, instead of from one only, a wire should come from this to the under part of the rubber, as is frequently the case. Great care is required in warming and there be connected with a piece of tin-foil running the this machine, lest the plate should become unequally hented and whole length of it. This is often omitted, but as the materials, crack. The best plan is to lay some silk handkerchiefs over of the rubber are not good conductors, this simple addition it, and let it stand a little way from the fire. greatly increases the power. The chain from the hook should Ebonite or vulcanite is now sometimes used in place of glass be allowed to touch the ground, or, better still, be connected for the plate, and possesses many advantages over it. A larger with a gas pipe, as thus a plentiful supply of electricity will be amount of electricity may be obtained from it, and it is not obtained from the earth, which is the great reservoir of it. The liable to crack as a glass plate is, nor does the damp condense conductor of the machine may be made as shown in Fig. 6, on it so readily. Still, it is much softer, and therefore will but is rather more convenient, if mounted on a separate stand not wear quite so long. For an ebonite plate, hareskin is one The points, too, instead of being placed along the side, may be of the best materials for use in the construction of the rubber

. fixed on a separate piece fitting into one end of the conductor. It must be thoroughly cleansed from grease, and the amalgami A very good fork may be made by rounding the ends of a piece used must be softer than that used with glass. of wood about the size of a small ruler, covering it with tin Plate machines have occasionally been constructed with two foil, and inserting a row of needles along one side. The prime or more plates fixed parallel to one another on the same axis

. conductor, also, may be made of wood covered with tin-foil, A much greater increase of power is, however, obtained by the and should have its end somewhat bulging, as shown in the use of a very large plate. At the London Polytechnic there is engraving.

one with a plate about seven feet in diameter, and driven by a When the machine is wanted for use, every part should be care- small steam-engine, from which sparks of great length and fully

rubbed dry and clean with warm cloths. The rubber screw power may be obtained ; and even this size has been exceeded, should be loosened, and the rubber turned back, so as to allow for some time ago there was one at the Panopticon with a tenof the old amalgam being scraped off, and a fresh supply placed feet plate. Machines of this size require, of course, great care on the cashion under the silk flap. It may then be replaced in their use, as a spark from one of them would be nearly sufand pressed firmly against the cylinder by means of the screw, ficient to knock a man down, and injurious effects might posor by the pressure of the hand on it.

sibly be produced Now turn the cylinder, and if the machine be in a darkened Several other machines for producing electricity, or modified

tions of the preceding, have been tried with varying degrees was learned and studied from him alone. He threw all his of success, but scarcely any of them are enough used to call for predecessors into the shade, and nearly all subsequent historians our attention here. The only one we shall refer to is that confined themselves to abridging his work." known as Armstrong's hydro-electric machine (Fig. 8). Some According to the early legends, the original inhabitants of years ago it was noticed that when steam was issuing rapidly from Rome were almost entirely men, and being mostly criminals and a boiler, sparks were at times given off from it. Sir William runaway slaves, they found it impossible to obtain any of the Armstrong investigated the phenomenon, and was thus led to women of the neighbouring states in marriage. In this difficulty, devise the machine we are now about to explain.

Romulus, the king and founder of the city, had recourse to an The body of it consists of an ordinary steam-boiler, complete artifice. He invited the Sabines to a festival at Rome, and they with furnace, tubes, etc. A water-gauge, to show the level of came without suspicion, bringing their wives and daughters; the water, is seen at the side, and a safety-valve is fitted to but in the midst of the festivities the Romans rushed on them it above. When the steam has acquired sufficient pressure, the with drawn swords, and carried off a great number of the women tap, c, is turned on, and the stearn then escapes through the (the rape of the Sabines). War ensued, and a battle was fought jets at A. These jets are formed of box-wood, as shown in which seemed likely to have ended in the total destruction of section at M, so that the steam is not allowed to escape in an the Sabine army. At this crisis our first extract comes in :uninterrupted way, but is caused, by means of a bent piece of

LIVY, I. 13. metal, to strike against the sides of the mouth-piece. The box, B, is filled with cold water, which partially condenses the steam

Tum Sabinæ mulieres, quarum ex injuria' bellam ortum erat, before it issues. When the steam is allowed to issue in this crinibus passis, scissaque veste, victo malis muliebri pavare, way from the jets, it will be found to be highly charged with ausæ se inter tela volantia inferre, ex transverso impetu facto positive electricity, which may be collected by a number of dirimere infestas acies, dirimere iras, hinc patres, hinc virogt points or a bundle of wires, P, supported on an insulating stand orantes, ne sanguine se nefando soceri generique respergerent, and connected with a prime conductor, D.

ne parricidio macularent partus suos, nepotum illi, hi liberum The boiler itself is supported on stout glass legs, and be progeniem. “Si affinitatis inter vos, si connubii piget, in nos comes very highly charged with negative electricity--so much vertite iras: nos cansa belli, nos vulnerum ao cædium viris ac so that sparks nearly two feet in length have been obtained parentibus sumus, melius& peribimus quam sine alteris vestrum from a machine of this kind.

viduæ aut orbæ vivemus.” Movet res quum multitudinem, tumo If acid or a salt be added to the water in the boiler, all duces ; silentium et repentina fit quies : inde ad fædus faciendum evolution of electricity will cease ; if oil be added, the boiler duces prodeant, nec pacem modo sed civitatem unam ex duabus will become positively charged, and the steam negatively.

faciunt, regnum consociant, imperium omne conferunt Romam.10 In this machine, as in the others we have considered, the Ita geminata urbe ut Sabinis tamen aliquid daretur, Quirites a real cause of the electricity is friction. The steam becomes

Curibus appellati. partially condensed, and therefore contains a number of minute

NOTES. globules of water. These, being carried along with the steam, 1. Quarum ex injuria. The genitive of the object : from the injury strike violently against the tongue, and, by their friction done to whom. against it and the sides, evolve the electricity. If perfectly

2. Victo, abl. absolute, agreeing with pavore: the fear natural to their dry steam be used, or if the jets allow a free passzge, no elec. sex being overcome by the horrors of the scene.

3. Impetu facto, rushing across, between the combatants., tricity will be produced.

4. Patres—viros, their fathers, who were Sabines; their husbands, the Romans, who had forcibly married them.

5. Ne sanguine, etc., not to stain themselves with impious blood; these READINGS IN LATIN.-V.

of their fathers-in-law, the others of their sons-in-law.

6. Nepotum-liberum, grandsons to their fathers, the Sabines ; sons LIVY.

to their husbands, the Romans. TITUS LIVIUS, the greatest of the Roman historians, was born

7. Si affinitatis, “If,they say. The construction changes from the at Patavium, the modern Padua, about 60 B.C., and died in the ratio obliqua to the oratio recta, in which the actual words of the year 20 A.D. From the name of his birthplace he is called speakers are reported.

8. Melius, it will be better for us to die. Patavinus, and the occasional provincial expressions which some

9. Quum-tum, first one, then the other, and so both, and. critics have affected to detect in his style have been called, from 10. Conferunt Romam, lit., they bring together to Rome; they conthe same cause, Patavinitas. He is said, in his earlier years, to centrate at Rome. Romam, accusative of motion to a place. have published some works on rhetoric, but the recollection of these has been eclipsed by the magnificence and colossal pro- that is no doubt well known to most of our readers, the defence of

Our second extract is part of the account of a deed of bravery portions of his history of Rome from the earliest period down to the bridge by Horatias Cocles, which forms the subject of the best his own days. Of this work comparatively a small portion has of Macaulay's " Lays of Ancient Rome.” The last of the kings reached us. It is believed that he intended completing it in 150 of Rome, Tarquinias Superbus, who had been driven from the books, divided into fifteen decads or sets of ten books each, and state for his great cruelties, made several vigorous efforts to reof these he wrote 142. All that are extant in their entirety are gain the crown he had lost. He summoned to his aid Porsenna, the first, third, and fourth decads—in other words, Books I.-X. lord of the neighbouring state of Clusiam, who came with a and XX.-XL. The only other remains are abstracts of the conand CXXXVII., and a few isolated fragments. Though con- ing the entrance of Porsenna's army, but the enemy were close tents of all the 142 books, with the exception of Books CXXXVI. strong army to attack Rome. The only hope for the Romans

lay in breaking down the bridge over the Tiber, and so preventtaining occasional obscurities, the style of Livy's writing is, as upon them before they accomplished their object. In this 2 whole, remarkably pure and elegant, and his descriptions are junctare a brave Roman, named Horatius, volunteered to keep always forcible and picturesque. As a statement of facts his the passage of the bridge, with two of his friends, until the account of the early period of Roman history is not to be Romans should be able to cut it down :depended upon, though for a long time it was accepted as true; and it was reserved for Niebuhr, one of the greatest of German

LIVY, II. 10, 5. scholars, to show that Livy had, in the absence of more reliable Vadit inde (Horatius) in primum aditum pontis, insignisque authorities, merely taken for granted and repeated the stories of inter conspecta cedentium pugnæ terga obversis comminus ad the old annalists, which were in point of fact little

better than ineundum prælium armis ipso miraculo audaciæ obstupefecit fabulous, without taking the trouble to examine them critically; hostes. Duos tamen cum eo pudor tenuit Sp. Lartium ac T. but as the work proceeds it increases in historical value. Herminium ambos claros genere factisque. Cum his primam Niebuhr says of him, "Few authors have exercised an influ- periculi procellam, et quod tumultuosissimum pugna erat, ence like that of Livy; he forms an era in Roman literature; parumper sustinuit: deinde eos quoque ipsos exigua parte and after him, no attempt was made to write Roman annals

. pontis relicta, revocantibus: qui rescindebant, cedere in tutum His reputation was extraordinary. It is well known that one coegit

. Circumferens inde truces minaciter oculos ad proceres man came from Cadiz to Rome merely to see Livy; and this re- Etruscorum,“ nunc singulos provocare, nunc increpares omnes, putation was not ephemeral; it lasted and became firmly esta- servitia” regum superborum suæ libertatis immemores, alienam blished. Livy was regarded as the historian, and Roman history oppugnatum venire. Cunctati aliquamdia sunt, dum alius alium,

OF HERSCHEL.

ut prælium incipiant, circumspectant. Pudor deinde commovit

Plain in thy neatness? Oh how oft shall be aciem, et clamore sublato indigne in unum hostem tela conji

On faith and changed gods complain, and seas ciunt. Qua quum in objecto cuncta scuto hæsissent, neque ille

Rough with black winds and storms minus obstinatus ingenti pontem obtineret gradu, jam impetu

Unwonted shall admire. conabantur detrudere virum, quum simul fragor rupti pontis, Who now enjoys thee credulous, all gold, simul clamor Romanorum alacritate perfecti operis sublatus,

Who always vacant, always amiable pavore subito impetum sustinuit. Tum Cocles, “Tiberine

Hopes thee, of flattering gales pater," inquit, “te sancte precor, hæc arma et hunc militem

Unmindful, Hapless they propitio flumine accipias." Ita sic armatus in Tiberim desiluit,

To whom thon untried seem'st fair. Me in my vowed multisque super incidentibus telis incolumis ad suos tranavit,

Picture the sacred wall declares to have hung rem ausus plas famæ habituram ad posteros quam fidei. Grata

My dank and dropping weeds erga tantam virtutem civitas fuit; statua in comitio posita,

To the stera god of sea.-Millon. agri quantum uno die circumaravit datum.

NOTES. 1. Cedentium pugnæ, retreating ; lit., yielding to the battle.

LESSONS IN ASTRONOMY.-IV. 2. Et quod, etc., the most tumultuous part of the fray. 3: Revocantibusc, etc., while they who were cutting down the bridge vere RESULTS OF NEWTON'S LAWS-FOUNDATION OF THE ROYAL calling them to come back.

OBSERVATORY - FLAMSTEED-HALLEY -CALCULATION OF 4. Etruscorum, Clusium, from whence Porsenna came, was a city

ORBIT OF COMET-BRADLEY-BODE'S LAW-DISCOVERIES of Etruria. 5. Provocare-increpare, historical infinitives.

THE grand discovery of Newton seems to have completed our 6. Servitia, put for servos, the abstract for the concrete. So knowledge of the fundamental laws of motion of the worlds we find militia for milites ; juventus for juvenes. To agree with it Live around us, and has afforded to us another most conrincing puts immemores, a constructio kara güveGW (according to the sense).

7. Suæ libertatis, etc. The infin. venire depends upon the verb proof of the wisdom and power of Him who created all things. increpare; taunting them for coming, slaves of a proud king as they To make and sustain these bodies requires the power of Omni. were, and careless of their own freedom, to attack the freedom of others. potence; but when we find that all their motions depend on the

8. Oppugnatum ; supine in um; after venire, a verb of motion. two simple laws of inertia and mutual attraction, and that all 9. In unum hostem, on their solitary foe.

their variations and movements can be fully explained by these; 10. Conabantur, etc., hostes, when the darts had stuck fast the enemy and further, when deeper investigation shows us that though (who hnd thrown them) endeavoured. 11. Plus famæ, etc., destined to gain among posterity more fame than through fixed and certain cycles, so that their very fluctuations

all the stars are in ceaseless motion, yet these motions run credit, 12. Comitio. The comitium, the place of meetiug of the comitia, or

ensure the stability of the entire system, we are lost in admirapublic assemblage, was a part of the Forum.

tion at the wisdom of the great and omnipotent Architect of the

Universe. In the course of a war (B.c. 319) with the Samnites, a people who inhabited the country north of Campania, the Roman army his task. He discovered the mutual attractions of the heavenly

Great as Newton's work was, he did not live to complete all were entrapped in a narrow defile called the Furculæ Caudinæ, bodies for one another, but left it to succeeding astronomers to or Caudine Forks, and were obliged to surrender. The following calculate the effects this attraction would produce on the move extract is remarkable as being one of the few descriptions of ments of each. That this was a work involving no slight scenery found in the Latin authors :

difficulty will easily be seen if we consider the case of only LIVY, IX. 2, 4.

a single planet. For illustration, we will take Venus. Suppose Duæ ad Luceriam ferebant viæ altera præter oram superi now for an instant that only this planet and the Sun existed, maris' patens apertaque sed quanto tutior tanto fere longior, we could then easily mark out the exact position of the planet altera per Furculas Caudinas brevior. Sed ita natuslocus est: for every moment if we know its mean distance and the eccensaltus duo alti angusti silvosique sunt montibus circa perpetuis tricity of its orbit. Now add the Earth to the system, and wa inter se juncti : jacet inter eos satis patens clausus in medio shall find that a disturbing influence is at once introduced by campus herbidus aquosusque, per quem medium iter est : sed its attraction. As Venus comes in the part of its course nearest ante quam venias ad eum, intrandæ primæ angustiæ sunt, et the Earth, it is attracted by it, and thus drawn out of its path; ant eadem, qua te insinuaveris, retro via repetenda, aut si ire its motion is likewise accelerated as it approaches the Earth

, porro pergas, per alium saltum arctiorem impeditioremque and retarded as it recedes from it; and the calculation of the evadendum. In eum campum via alia per cavam rupem Romani amount of this disturbance is rendered more difficult by the remisso agmine, quoniam ad alias angustias protinus pergerent,? fact that the Earth is itself moving at a rate different from septas dejectu arborum saxorumque ingentium objacentem that of Venus. molem invenere. Quum fraus hostilis apparuisset, præsidium

When we have made allowance for this disturbance, we etiam in summo saltu conspicitur:S citati inde retro, qua vene- have to consider the effects produced by each of the other rant, pergunt repetere viam: cam quoque clausam sua' obice planets in turn, remembering that they too are all in motion. armisque inveniunt.

We thus get some idea of the complication of the problem. NOTES.

It has, however, been completely worked out by modern astrono1. Superi maris, the Adriatic, which lies to the north-east of Italy, mers, the due allowance being made for each of these disturbing and so above it, as opposed to the mare inferum, or Tyrrhenum, which forces; and, as we shall learn by and by, this has been done lies to the south-west.

2. Quanto tutior, etc. In a comparison of two qualities which are with such astounding accuracy that when certain minute irregu. found in the same thing in an unequal degree, the one varying

with the larities were discovered in the motions of one of the planeta other, the Latins use two comparatives; we use the positive. Lit., as which could not be accounted for by the influence of any of the long as it was secure, its length being proportionate to its security.

known ones, it was conjectured that another planet must exist 3. Ita natus, the nature of the spot is as follows.

beyond them. Two astronomers, accordingly, quite indepen. 4. Satis patens, of tolerably wide extent.

dently of each other, set about the calculation, and determined 5. Venias-.e., you, the reader.

the very spot in which such a planet ought to be, if it existed 6. Cavam rupem, through a rocky gorge.

at all; and on turning a telescope to that spot, the planet 7. Protinns pergerent, had got right through to the defile at the other end. (Neptune) was found, though at no portion of its orbit could it 8. Dejectu arborum, put for dejectis arboribus.

2. Conspicitur, the change to the present adds vividness and force come within 130,000,000 miles of the planet whose course had to the description,

been disturbed by its attraction. 10. Sua, with its barrier, just like the other.

One fact we particularly notice as the result of these investi.

gations, and that is the absolute stability of the system, it being Poetical Translation of HORACE, "ODES,” I. v., in last Reading. so beautifully balanced that all these perturbations exactly What slender youth, bedewed with liquid odours,

compensate one for another, and after an infinite cycle all Courts thee on roses in some pleasant cave,

return to their original places. Pyrrha ? For whom bind'st thou

Flamsteed was another celebrated astronomer, almost cotIn wreaths thy golden hair,

temporary with Newton, and was the first Astronomer Royal,

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