and Seneca affirms that money has been fused in a purse without the latter being burnt.

The preceding are examples of the mechanical effects of lightning. It works chemically as well. It has the power of developing a peculiar odour, somewhat like the fumes of burning sulphur. Wafer mentions a storm on the Isthmus of Darien, which diffused such a sulphureous stench throughout the atmosphere, that he and his companions could scarcely draw their breath, particularly when the party plunged into the woods. Nitric acid, too, is formed in the atmosphere by lightning. Liebig, having collected seventyseven samples of rain water, found that seventeen which had fallen during thunder-storms contained nitric acid in greater or smaller quantities, while the remaining sixty, drawn from the clouds in times of peace, exhibited no traces of this virulent liquid. Arago suggests that further investigations on this point may lead to some inferences respecting the supply of those natural deposits of nitre, the existence of which, in certain localities where no animal matter is to be found, is so difficult to explain. "There would be something particularly curious," he adds, "in showing that thunderbolts prepare, in the upper regions of the atmosphere, the principal element of that other thunderbolt of which men make such prodigious use for mutual destruction.”

Lightning can also produce magnetic effects, as common electricity is well known to do. A shoemaker in Swabia had his tools thus magnetized, to his indescribable annoyance. He had to be constantly freeing his hammer, pincers, and knife, from the nails, needles, and awls, which were getting caught by them as they lay together on the bench. The poor fellow, who was of course no philosopher, was compelled to relinquish the use of his bewitched implements. If lightning gets into a clock or chronometer, it will so magnetize the works as to vitiate their operations completely. Still more dangerous is the power which it possesses of altering, or even destroying magnetism where it already exists. Nearly two centuries ago, a couple of English ships were sailing from London to Barbadoes. On the voyage, a flash of lightning fell upon one of the vessels,

but inflicted no damage on the other. Suddenly the captain of the suffering ship was observed to alter his course, and turn his prow, as if making for England again. His consort inquired the reason, and found that the whole crew believed they were still proceeding to Barbadoes. A careful inspection of the compasses proved that the poles had been completely reversed by the lightning. Had this event happened to a solitary ship, what would the captain have thought when the shores of the Old World rose up before him, while engaged in a fruitless hunt for those of the New! Many other effects have been attributed to electrical commotions, for which it would be hazardous to vouch; and divers small charges also are often brought against the thundering Jove. Says the dairyman, "You have curdled my milk!" "And soured my beer!" continues the brewer. "And tainted my fresh meat!" cries the irritated butcher. For these accusations, however-whimsical as they seemit would be difficult to say that there is no foundation, when we remember that nitric acid is formed during thunder, and that the electric fluid develops a peculiar effluvium.

The mischievous propensities of lightning have compelled men to inquire whether something may not be done to avert or disarm this devastating meteor. And happily, after many abortive plans and projects, science has at length taught us how Jove's darts may be blunted. The principle adopted is not that of repelling the enemy; for if the lightning is prepared to strike, it is idle to think of arresting the stroke. It is found to be the safest policy to treat with the enemy, and to receive his advances courteously. Let him be provided with an easy route, and he may be prevailed upon to make a mild journey from the skies, instead of darting explosively to the earth. A plain copper rod, with its top peering above the roof of a house, and its other extremity sunk in the ground, may seem to be a contrivance little fitted to persuade the lightning to leave the house untouched, and to walk off by the rod into the earth. But the philosophy embodied in this simple apparatus is the result of many years of research; and experience proves that the research has not been expended in vain. What is

wanted is a conductor, in traversing which the lightning will meet with the least resistance. And as copper is found to be of all substances the best transmitter of electricity, soin order to drain off the dangerous fluid from the cloud to the earth, and to prevent it from making your house, or ship, or steeple, its pathway-you have only to provide a copper rod, considerably elevated above the object to be protected, of sufficient diameter to carry a good cargo of lightning without melting under its fiery load, continuous in its structure from end to end, and pointed at its upper extremity. All honour to an invention which can shield the gallant ship at sea and the stately building on shore with equal effect from the deadly bolt-which can guide the hissing shaft from the sky, and bury it deep in the soil, a powerless and extinguished thing—and which, plucking the fiery sting from the spirit of the storm, can leave him to pursue his course, muttering a few empty menaces, or dissipating his wrath in harmless fulminations!

Abridged from the BRITISH QUARTERLY REVIEW.

SHIPWRECK IN A CALM.

THE Moon is sunk, and a clouded gray
Declares that her course is run;
And like a god who brings the day,

Up mounts the glorious Sun.

Soon as the light has warmed the seas,

From the parting cloud fresh blows the breeze;
And that is the spirit whose well-known song
Makes the Vessel to sail in joy along.
No fears hath she;-her giant-form,
O'er wrathful surge, through blackening storm,
Majestically calm would go,

'Mid the deep darkness white as snow!
But gently now the small waves glide,
Like playful lambs o'er a mountain's side.
So stately her bearing, so proud her array,
The Main she will traverse for ever and aye.
Many ports will exult at the gleam of her mast—

Hush! hush! thou vain dreamer! this hour is her last.

Five hundred souls in one instant of dread

Are hurried o'er the deck;

And fast the miserable Ship

Becomes a lifeless wreck.

Her keel hath struck on a hidden rock,

Her planks are torn asunder,

And down come her masts with a reeling shock,

And a hideous crash like thunder.

Her sails are draggled in the brine,
That gladdened late the skies,

And her pendant that kissed the fair moonshine
Down many a fathom lies.

Oh! many a dream was in the Ship,

An hour before her death;

And sights of home with sighs disturbed
The sleeper's long-drawn breath.
Instead of the murmur of the sea,
The sailor heard the humming tree
Alive through all its leaves,
The hum of the spreading sycamore
That grows before his cottage-door,
And the swallow's song in the eaves;
His arms enclosed a blooming boy,
Who listened with tears of sorrow and joy
To the dangers his father had passed;
And his wife-by turns she wept and smiled,
As she looked on the father of her child

Returned to her at last :

-He wakes at the Vessel's sudden roll,
And the rush of waters is in his soul;
Astounded the reeling deck he paces,
'Mid hurrying forms and ghastly faces-
The whole Ship's crew are there!
Wailings around and overhead,
Brave spirits stupified or dead,
And madness and despair.

Now is the Ocean's bosom bare,
Unbroken as the floating air;
The Ship hath melted quite away,
Like a struggling dream at break of day.
No image meets iny wandering eye

But the new-risen sun, and the sunny sky.

Though the night-shades are gone, yet a vapour dull
Bedims the waves so beautiful;

While a low and melancholy moan
Mourns for the glory that hath flown.

WILSON.

THE ELECTRIC TELEGRAPH.

As the etymology of the word implies (Gr. tele, distant, and grapho, I write), a telegraphic instrument is used for the conveyance of messages or signals to a distance. Various methods are employed for this purpose, but none has been so widely applied, or has proved so beneficial in its use, as the electric telegraph. This method of telegraphing is accomplished by setting up a current of electricity between. the places from and to which messages are intended to be sent, and employing it in the production of visible or audible signals representing letters and words. The apparatus employed consists essentially of three distinct portions, viz., the voltaic battery, by which electricity is generated; the wires, by means of which the electric force is transmitted; and the instruments, which regulate its transmission for the conveyance of messages.

If a plate of zinc and a plate of copper be placed side by side, but without touching, in a vessel containing water to which a small proportion of sulphuric acid has been added, no electric action will be manifested. If, however, the plates be made to touch at a point outside the liquid, or if, as in the annexed figure, a metal wire be attached to each, and the two wires be brought into contact, an electric current is immediately set in action. The direction of this current is always from the zinc plate Z through the liquid, to the copper plate C, and thence along the

B

wires A B, by their junction at D, to the zinc plate again. This the simplest form of a voltaic cell produces only a feeble current. Those generally used for telegraphic purposes, though the same in principle, differ from it more