ordinary fact of the kind we have met with is to be found in the Encyclopædia Britannica, article London, where we are told that the illumination of the atmosphere by the great fire of London was visible at Jedburgh, in Scotland, three hundred and seventy-three miles distant!

ROCKING STONES.

Rocking stones, or stones of prodigious size so exactly poised that they will rock or shake with the smallest force, were known to ancient as well as modern topography. Pliny tells us that at Harpasa, a town of Asia, there was a rock of such a wonderful nature that if touched with the finger it would shake, but could not be moved from its place with the whole force of the body. Ptolemy Hephestion mentions a stone near the ocean, which was agitated when struck by the stalk of an asphodel, but could not be removed by a great exertion of force.

In Britain there are many stones of this description. In the parish of St. Leven, Cornwall, there is a promontory called Castle Treryn. On the western side of the middle group, near the top, lies a very large stone, so evenly poised that any hand may move it from one side to another; yet it is so fixed on its base that no lever, nor any mechanical force, can remove it from its present situation. It is called the Logan (Logging) Stone, and is at such a height from the ground that no person can believe that it was raised to its present position by art.

Other rocking stones are so shaped, and so situated, that there can be no doubt they were erected by human strength. Of this kind Borlase thinks the great Quoit, or Karn-lehau, in the parish of Tywidnek, to be. It is thirty-nine feet in circumference, and four feet thick at a medium, and stands on a single pedestal. There is also a remarkable stone of the same kind in the island of St. Agnes, in Scilly. It is poised on a mass of rock ten feet six inches high, forty-seven feet round the middle, and touching the ground with no more than half its base. From this the rocking stone rises on one

point only, and is so nicely balanced that two or three men with a pole can move it. It is eight feet six inches high, and forty-seven feet in circumference. On the top there is a basin, hollowed out, three feet eleven inches in diameter at a medium, but wider at the brim, and three feet deep. From the globular shape of this upper stone, it seems highly probable that it was rounded by human art, and perhaps even placed on its pedestal by human strength.

In Sithney parish, near Helston, in Cornwall, stood the famous Logan, or rocking stone, commonly called Men Amber, Men-au-bar, or the top stone. It was eleven feet by six, and four high, and so nicely poised on another stone that a little child could move it; and all travellers who passed that way desired to see it. But Shrubsall, Cromwell's governor of Pendennis, with much ado, caused it to be undermined, to the great grief of the parish. There are some marks of the tool upon it; and, by its quadrangular shape, it was probably dedicated to Mercury.

In the parish of Kirkmichael, in Scotland, there is a very remarkable stone of this description. It stands on a flat-topped eminence, surrounded at some distance by steep, rocky hills. It rests on the plain surface of a rock, level with the ground. Its shape is quadrangular, approaching the figure of a rhombus, of which the greater diagonal is seven feet and the lesser five. Its medium thickness is about two feet and a half: its solid contents are, therefore, about 51,075 cubical feet. As it is of very hard and solid whinstone, its weight, estimating the cubic foot at one hundred and fifteen pounds, may be reckoned to be five thousand eight hundred and fifty-seven pounds, or nearly three tons. It touches the rock on which it rests only in one line, which is in the same plane with the lesser diagonal, and its lower surface is convex towards the extremities of the greater diagonal. By pressing down either of the extreme corners and withdrawing the pressure alternately, a rocking motion is produced, which may be increased so much that the distance between the lowest depression and the highest

elevation is a full foot. When the pressure is wholly withdrawn, the stone will continue to rock till it has made twenty-six or more vibrations, from one side to the other, before it settles in its natural horizontal position. Both the lower side of the stone, and the surface of the rock on which it rests, appear to be worn smooth by mutual friction.

It seems generally agreed that the rocking stones of Britain were monuments erected by the Druids; but tradition has not informed us for what purpose they were intended. Mr. Toland thinks that the Druids made the people believe that they alone could move them, and that by a miracle; and that by this pretended miracle they condemned or acquitted the accused, and brought criminals to confess what could not otherwise be extorted from them. This idea is thus beautifully alluded to by Mason:

Behold yon huge

And unhewn sphere of living adamant,

Which, poised by magic, rests its central weight
On yonder pointed rock. Firm as it seems,
Such is its strange and virtuous property,
It moves obsequiously to the gentlest touch
Of him whose breast is pure; but to a traitor,
Tho' e'en a giant's prowess nerved his arm,
It stands as fixed as Snowdon.

THE BLACK HOLE AT CALCUTTA.

This celebrated place of confinement was only eighteen feet by eighteen, containing, therefore, three hundred and twenty-four square feet. When Fort William was taken, in 1756, by Surajah Dowla, Nabob of Bengal, one hundred and forty-six persons were shut up in the Black Hole. The room allowed to each person a space of twenty-six and a half inches by twelve inches, which was just sufficient to hold them without their pressing violently on each other. To this dungeon there was but one small grated window, and, the weather being very sultry, the air within could neither circulate nor be changed. In less than an hour, many of the prisoners were attacked with extreme difficulty of breathing; several were delirious; and the place was

filled with incoherent ravings, in which the cry for water was predominant. This was handed them by the sentinels, but without the effect of allaying their thirst. In less than four hours, many were suffocated, or died in violent delirium. In five hours, the survivors, except those at the grate, were frantic and outrageous. At length most of them became insensible. Eleven hours after they were imprisoned, twenty-three only, of the one hundred and forty-six, came out alive, and those were in a highly-putrid fever, from which, however, by fresh air and proper attention, they gradually recovered.

STONE BAROMETER.

A Finland newspaper mentions a stone in the northern part of Finland, which serves the inhabitants instead of a barometer. This stone, which they call Ilmakiur, turns black, or blackish gray, when it is going to rain, but on the approach of fine weather it is covered with white spots. Probably it is a fossil mixed with clay, and containing rock-salt, nitre, or ammonia, which, according to the greater or less degree of dampness of the atmosphere, attracts it, or otherwise. In the latter case the salt appears, forming the white spots.

BITTERNESS OF STRYCHNIA.

Strychnia, the active principle of the Nux Vomica bean, which has become so famous in the annals of criminal poisoning, is so intensely bitter that it will impart a sensibly bitter taste to six hundred thousand times its weight of water.

SALT, AS A LUXURY.

Mungo Park describes salt as "the greatest of all luxuries in Central Africa." Says he, "It would appear strange to a European to see a child suck a piece of rock-salt, as if it were sugar. This, however, I have frequently seen; although in the inland parts the poorer class of inhabitants are so very rarely indulged with this precious article, that to say a man eats salt with his victuals is the same as saying that he is a

rich man. I have myself suffered great inconvenience from the scarcity of this article. The long-continued use of vegetable food creates so painful a longing for salt, that no words can sufficiently describe it."

SINGULAR CHANGE OF TASTE.

The sense by which we appreciate the sweetness of bodies is liable to singular modifications. Thus, the leaves of the Gymnema sylvestre,-a plant of Northern India,-when chewed, take away the power of tasting sugar for twenty-four hours, without otherwise injuring the general sense of taste.

BLUNDERS OF PAINTERS.

Tintoret, an Italian painter, in a picture of the Children of Israel gathering manna, has taken the precaution to arm them with the modern invention of guns. Cigoli painted the aged Simeon at the circumcision of the infant Saviour; and as aged men in these days wear spectacles, the artist has shown his sagacity by placing them on Simeon's nose. In a picture by Verrio of Christ healing the sick, the lookers-on are represented as standing with periwigs on their heads. To match, or rather to exceed, this ludicrous representation, Durer has painted the expulsion of Adam and Eve from the Garden of Eden by an angel in a dress fashionably trimmed with flounces. The same painter, in his scene of Peter denying Christ, represents a Roman soldier very comfortably smoking a pipe of tobacco. A Dutch painter, in a picture of the Wise Men worshipping the Holy Child, has drawn one of them in a large white surplice, and in boots and spurs, and he is in the act of presenting to the child a model of a Dutch man-of-war. In a Dutch picture of Abraham offering up his son, instead of the patriarch's "stretching forth his hand and taking the knife," as the Scriptures inform us, he is represented as using a more effectual and modern instrument: he is holding to Isaac's head a blunderbuss. Berlin represents in a picture the Virgin and Child listening to a violin; and in another picture he has drawn King