heartbroken, and spent in brain. She falls into a death in life, and remains to all appearance as one dead. When consciousness confusedly returns, she finds herself unable to move as to her body, which is laid in the chapel, and in a dim dream state as to the mind. Opposite the bier is a window like a great eye; it is dark, but time for moonrise.

And then as there I lay a-swoon,

All gradually the air wax'd white With some strange pallor of affright, And through the heavens the witch-pale

moon

Slid slowly up into the night.

A fearful fire enters the limbs, old instincts seem burnt out, and fiendish hungers effect an entrance. The churchyard opens to the sight, and the intense will strains out to reach the rill of blood that seems to run red from the veins of the buried folk. When first light of morning comes the awful sight vanishes, and a horrible sleep creeps on again. A new experience, however follows:

But gradually within my dream,

Another dream was born in me :
Methought God's sunshine set me free
From doom of dark; and it did seem
One knelt anigh on bended knee.
And gazed full sadly on my face,

With eyes starsoft, eyes that I knew, Fill'd with full peace of heaven's hue; Wherein big tears did stand and chase

Each other from their deeps of blue.

It is the knight returned safe and sound, and the spell slides off, the glad eyes open, and with a cry of the people, the dead comes to life again, only to swoon in her lover's arms. The days pass in blank swiftness to the girl until the wedding with her recovered knight. The next scene is of Lautrec asleep, with his wife with proud love gazing on his form. And more especially my sight

Sate on the glory of his throat :
With fondling fingers did I note
The part where it was left milk white,
And that whereon the full sun smote

And burnt its pallor golden brown.
Then as my toying hand withdrew
The coverlet of gold and blue
From off his breast, and creeping down,
Did nestle in his bosom true,

I saw whereas the royal line

Of his fair throat met with the snow Of the broad breast, and curling slow, Blended-a crescent purpurine,

That on the milky flesh did glow

Like angry birth of harvest moon:
'Twas where some cruel sword had let
Well nigh the life out. But I set
My lips unto it, half a-swoon,

For thinking of the cruel fret

Of pain that there had throbb'd whilere.
And as I kissed the scarce heal'd scar,
A dim foreboding, faint and far,
Rose through my rapture, seeing there
The image of the midnight star.

Alas! the star was but the ominous forerunner of the moon, who comes to gloat upon her prey, and brings on again the old nerve madness felt before in the chapel on the bier. The awful vampire visions flood space anew, and the end needs scarce the telling. The scar that was kissed before becomes the horrible temptation of the vampire thirst. Lautrec's blood gives birth to a surge of fiend life in the body that had reverted to its leaden swoon. Lautrec's life slowly ebbs, and he dies. When morn comes and breaks the sorcery, the woman dies forthright at sense of what is done; but the curse remains of her subjection as a corpse to the "cold hermetic fire" that makes the nightly raven in her veins, and the hapless girl is vampire complete.

A story to curdle the blood, and to urge one to give one's nerves as much as possible of pure air and wholesome sunlight, and as little as possible of passionate abandonment, selfish isolation, and moonlight. The subject is so powerfully treated by Mr. Payne, that we cannot but regret that he has not devoted his fine energies to something better.

THE panic which, within a few weeks, reduced the selling value of gas stock by some 30 per cent. has not been the less mischievous for being unreasonable. Such is is usually the case with any sudden burst, either of alarm or of confidence. In nine cases out of ten, whether we regard an alarm of fire in a church or a theatre, a run on a bank, or a sudden and heavy fall in market quotations, the panic is iin itself a more serious evil than its cause. And, as general counsel "not to be frightened" is rarely of much use, it may be important to many a doubting holder, or worse, non-holder, of a property that is generally paying some 10 per cent. on the expended capital, to inquire a little closely into the character of the electric light, and into the mode in which it is likely to come into competition with the light obtained from gas.

One of the earliest phenomena observed in connection with voltaic electricity was the production of the bright spark, resembling that obtained from the conductor of an electric machine, which occurs on making and breaking the circuit of the battery. Sir Humphrey Davy, in 1813, made experiments with a

very powerful battery to determine the length of spark which could thus be obtained, using two pieces of carbon as the terminus points of the conducting wires. Despretz, in 1850, made a series of further experiments, from which most of the scientific information attainable on the subject, down to very recent times, has been derived.

"If we approach," M. Fontaine remarks, "the two conductors of a sufficiently strong electric current to one another until they touch, and then gradually separate them, an extremely brilliant arc appears, which remains so long as the distance between the conductors is not too great." This luminous current has received the name of the Voltaic arc. It is also very generally known that if a portion of very fine wire be interposed in a circuit, of adequate intensity, carried through conductors of much greater diameter, the interposed portion becomes heated to a red, or even a white, heat. By this method the explosion of charges of gunpowder in mines (and more recently in electric torpedoes) has been effected for nearly forty years, the first practical application of

the method having been made in 1839, by the late General Pasley for blowing up the wreck of the Royal George at Spithead.

The various inventions now in course of development for utilising the light producible by the electric current, are all based on either one or the other of these two longknown phenomena. A wide range of conditions may be added to the production of either the luminous are or the incandescent wire. The phenomena may be produced in vacuo, or in nitrogen or other gas. Various metals may be employed, among which iridium is said to have produced the most striking results. The form as well as the material of the electrodes or approaching points may vary.

But the main improvement which underlies any practical effort to apply the light of electricity to industrial use has been the substitution of a magneto-electric machine for a pile or battery as the generator of the electric current. The Jablochkoff candle depends on the production of a voltaic arc, or rather of a constantly succeeding series of arcs produced in opposite directions. The Edison light depends on the production of incandescence in a strip of platinum.

The intimate nature of the relation existing between electric and magnetic phenomena was discovered by Erstedt, a Dane, in 1820. Volta's first arrangement, the pile, consisting of alternate plates of silver and zinc separated by moistened cloth, was invented in 1800. Galvani, of Bologna, was before this, the first observer of the phenomena attending on the contact of two different metals with an organic body. Davy constructed a magnificent battery of 2000 double plates of copper and zinc, each having a surface of thirty-two square inches. Daniel, in 1836, produced the first per

manent battery, as it was called comparatively, composed of zinc and copper plates, each immersed in a separate saline solution divided by porous diaphragms. Grove substituted platinum for copper, and Smee, when the process of electric metallurgy had sufficiently advanced to render it possible, substituted platinised silver for platinum. With all the improvements made, however, the galvanic battery, though a wonderful instrument in the hands of the physical philosopher, is a very inconvenient as well as a costly source for the steady supply of power which is to be available at any moment, as the chemical changes which occur in the elements of the battery while in action require constant attention and

correction.

The observation of Erstedt was the first discovery that led to the adoption of a more manageable form of electricity. He remarked that a magnetised needle was deflected from its direction when it was brought near a closed electric circuit, in the same way that it was deflected by the approach of a magnet. In the same year (Erstedt's experiment was repeated before the Academy of Sciences at Paris by M. de la Rive; and within a few days Ampere discovered the mutual action of magnets on each other, and Arago discovered that magnetic properties were imparted to iron by the elec tric current. Finally, in 1830, Faraday demonstrated that an electric current could be caused by a magnet.

Faraday showed that if a bar magnet were introduced into the centre of a coil or bobbin of insulated wire it produced an elec tric current through the coil. Con versely, when a bar of soft iron is placed in the centre of such a coil or bobbin, through which an elec

tric current is passed, the bar becomes magnetic so long as the current continues. Again, if two insulated coils or bobbins be made of such sizes that one can be freely passed into the interior of the other, the passing of an electric current through the one produces a current in the opposite direction through the other. This is called the induced current. It is in this phenomenon of induction, or the production in parallel layers, or concentric shells, of opposite tension or motion, without direct contact, that the main distinction between electric or magnetic phenomena and those of other physical agencies may be said chiefly to consist.

In 1832 Pixii, a philosophical instrument maker at Paris, constructed a machine to illustrate the experiments of Faraday, in which a horse-shoe magnet was made to revolve rapidly in face of two electro magnets, with the result of producing successive currents in opposite directions on each revolution. In Clarke's machine, the magnet, which is the most ponderous part of the arrangement, was fixed, and the electro-magnets were made to revolve. For the different purposes of electro-metallurgy, electro-blasting, decomposition of water, telegraphy, and production of light, a number of ingenious combinations have successively been produced. Finally, M. Gramme invented a machine, for which he received a gold medal and a prize of 3000 francs from the Société d'Encouragement, the construction of which has been the event that has turned the attention of so many ingenious men to the subject of lighting by electricity.

It will simplify any inquiry into the production of light by electricity to remember that there are four distinct operations necessary for that pur

pose. First is the electric source, of which we have to describe that which at the present moment is the most economical, namely, the magneto-electric machine of M. Gramme. Second may be considered the motor power requisite to drive the Gramme or other machine, and thus to excite the electric current. This has generally been a steam-engine. For small machines, where gas is readily attainable, a gas engine is usually found to be the cheapest and most convenient motor. Water power, again, is the cheapest mode, under certain circumstances, of producing, or rather of communicating, mechanical motion. Sir W. Armstrong has recently utilised the force of a waterfall, situated more than a mile from his house, as the motor power which drives an electromagnetic machine. If the difficulties attendant on the transmission of power be overcome, there is no doubt whatever that the enormous amount of tidal force exerted on our coasts (and even in London itself), and now almost wholly neglected as an economical agent, is ample to supply not only all the light, but all the heat, and all the motive power of any description that can be demanded by the inhabitants of our island. The question of the cost of such an application, however, is one of serious magnitude.

The third point of inquiry is as to the lamp, candle, regulator, or whatever be the name of that portion of the apparatus which allows the electric current to produce the phenomenon of light. And the fourth question regards the means of transmitting the current from the electric source to the illumina

tive apparatus, including not only the insulation of the carriers, but the division, regulation, or commutation of the current.

It is well here to remark that the

But

expression which has been used with reference to the operation of the Gramme machines, that it converts motion into electricity, is one that is as erroneous as if we were to say of a Cornish pumping engine that it converted motion, or fuel, into water. The electro-motor engine provides a supply of electricity at a given point, as the pump provides a supply of water. while we can form certain definite ideas of the latter element as to constitution and physical properties, we are far from being able to say as much as to electricity. That most patient and most brilliant of English physicists, Faraday, towards the close of his career, said that when he began to investigate electricity he thought that he understood the subject, but that as he learnt more he found that it was utterly beyond his power so to do. Heat is now generally regarded as a mode of motion. A definite unit of heat is commensurate with a definite unit of motion, and these units are reciprocally convertible. Such cannot be said to be the case with electricity. That influence, indeed, may be directed to the production of heat, as well as of light and of motion, and thermic changes have an electric effect. But whether electricity be called an element, or a current, or by whatever other name we may veil our ignorance of the great synthesis of phenomena called by that name, we cannot conceive of a motion apart from a something that moves. We can trace the path by which heat, or vibrations of different natures, pass through, over, and otherwise affect, different objects. But the phenomena of conduction and induction are so unmeasured, and the apparently unlimited amount to which the combinations of permanent magnets and electromagnets can be made to develop electric phenomena are so far

beyond the grasp of even the boldest hypothesis, that those writers on the subject are the wisest who most closely imitate the modesty of Faraday.

Returning now to the magnetoelectric machine of Gramme, which at the moment of writing is, all things considered, the best and most readily available of the numerous ingenious appliances known to be invented for the same purpose, we will endeavour to give a general idea of its principle and mode of action.

We have seen that if a helix or coil of wire be made part of an electric circuit, a bar of soft iron introduced within the helix becomes a temporary magnet; and that, conversely, if a bar magnet be introduced within a coil of wire, an electric current is set up in the wire by the introduction of the bar. M. Fontaine, to whose valuable treatise on electric lighting we have before referred, has illustrated this portion of the preliminary investigation of the subject by simple and intelligible dia

grams.

If the helix of which we speak be passed over the magnetic bar, or rather, if we consider the bar as being moved through the helix as a needle is pushed through a piece of cloth, a double action ensues. As the bar enters, a current is induced in the helix. But when the bar has passed half way, the neutral axis is reached. The opposite pole of the magnet is then approached, and the induced current that passes through the helix is reversed in its direction. Thus during the first half of the passage of the bar the induced current is direct, and during the second part it is inverted.

If two bar magnets are placed end to end, in a line, so that the similar poles are together, and the movement of a helix be made as