СНАР.

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as far as the experiments went, they fully corroborated the tables published many years ago by Dr. Lind, of Edinburgh, of which the following is a copy.

Scale of Pressure on One Square Foot.

Every policy of insurance should bind the owners, or masters of a ship insured, to provide a barometer; and the protest should be required to show that the barometer was registered at least once during every watch. But it ought to be registered oftener; and, within the tropics, during the hurricane season, every time the log is heaved.

Many of the sympiesometers are made too short; for which reason this sensitive and valuable instrument may fail at the moment it is most wanted. Thus, the oil of the sympiesometer of H. M. brig Racer, commanded by Captain James Hope, on the 29th of September, 1837, retired altogether from the column into the well; and then a bubbling was observed through the

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oil, which was no doubt the escape of the hydrogen gas, CHA P. owing to the high temperature and diminished atmospheric pressure acting conjointly. The number 12 had been entered on the log-board to denote the wind's force. Soon after this, though under bare poles at the time, the Racer upset; and was only saved by her masts giving way in about two minutes. She was running at the time with the wind two points abaft the beam on the starboard side; and she went over until her tops struck the waves. It is supposed to have been the sea rather than the wind which upset the Racer; for she was struck by a second wave before she recovered the lurch caused by the first.

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CHAP. XI.

On Waterspouts and the Smaller Whirlwinds.

CHAP. OF the different atmospheric phenomena, none is more curious than the waterspouts. That they cause small whirlwinds there seems no reason to doubt; and on this account, Horsburgh's description of them was introduced into the first chapter.

That which renders the waterspout so remarkable, is the circumstance of a double cone being formed when the phenomenon is complete, one cone pointing downwards from a cloud, whilst another points upwards from the sea. The thin semi-transparent columns, which stalk, as it were, on the surface of the ocean in calm weather, though no cloud is to be seen above them, as well as the small agitated circles, which are only seen by their marking the smooth surface of the sea in their gyrations, may probably have the same origin as the waterspout. One of these circles, which appeared too insignificant to do harm, after performing many gyrations near a ship commanded by Captain Marguis, on the coast of Malabar, suddenly approached her, as she lay becalmed, with her sails loose, and passing across her bows, carried off the flying jib and jib-boom into the air, higher than the mast-head. I have myself witnessed these semi-transparent columns, within the tropics, without being able to decide which way they turned round; and the spiral form in which they are said to revolve may be the reason for it is

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very difficult to pronounce which way a screw revolves CHAP. when turning rapidly. The figure being double, and the cones pointing in opposite directions, it should be observed whether the cloud above the spout also revolves, and if the gyrations of the upper portion of the phenomenon be in the same, or in the contrary, direction to those at the surface of the sea.

Beechey's

spout.

Notwithstanding diligent inquiry of a great many persons who witnessed waterspouts at sea, I have only been able to obtain one account in which the gyrations Captain of the wind are satisfactorily explained; and in this waterinstance it proved to be at the surface of the sea, turning in the contrary direction to the apparent law in great storms, in south latitude. The instance alluded to is the waterspout described by Captain Beechey, in the published account of his voyage in the Pacific, when he commanded the Blossom. That account says,

"While we were off Clermont Tonnerre, we had a narrow escape from a waterspout of more than ordinary size. It approached us amidst heavy rain, thunder, and lightning, and was not seen until it was very near to the ship. As soon as we were within its influence, a gust of wind obliged us to take in every sail, and the topsails, which could not be furled in time, were in danger of splitting. The wind blew with great violence, momentarily changing its direction, as if it were sweeping round in short spirals: the rain which fell in torrents was also precipitated in curves, with short intervals of cessation. Amidst this thick shower, the waterspout was discovered, extending in a tapering form, from a dense stratum of cloud to within thirty feet of the water, where it was hid by the foam of the sea, being whirled upwards by a tremendous gyration. It changed its direction after it was first seen, and threatened to pass over the ship but being diverted from its course by a heavy gust of wind, it gradually receded. On the dispersion of this magnificent phenomenon, we observed the column to diminish gradually, and at length to retire to the cloud from whence it had descended, in an undulating form.

:

CHAP.
XI.

"Various causes have been assigned for these formations, which appear to be intimately connected with electricity. On the present occasion, a ball of fire was observed to be precipitated into the sea, and one of the boats, which was away from the ship, was so surrounded by lightning, that Lieut. Belcher thought it advisable to get rid of the anchor by hanging it some fathoms under water, and to cover the seamen's muskets. From the accounts of this officer and Mr. Smyth, who were at a distance from the ship, the column of the waterspout first descended in a spiral form, until it met the ascending column a short distance from the sea; a second and a third were afterwards formed, which subsequently united into one large column, and this again separated into three small spirals, and then dispersed. It is not impossible that the highly rarefied air, confined by the woods encircling the Lagoon Islands, may contribute to the formation of these phenomena.

"Neither the barometer nor sympiesometer were sensibly affected by this partial disturbance of the atmosphere; but the temperature underwent a change of eight degrees, falling from 82° to 74° at midnight it rose to 78°. On the day succeeding this occurrence, several waterspouts were seen at a distance, the weather being squally and gloomy."

the

Clement Tonnerre is in south latitude, and is one of group of islands called "Dangerous Archipelago," about lat. 19° S., long. 137° W.

Having applied to Captain Beechey, in the hope that he might be able to explain in which way the gyrations of wind which accompanied this waterspout revolved, I received from him the following explanation:

"The gyrations were in a direction contrary to that of the hands of a watch; if it had been otherwise the ship would have changed her tack, whereas she only broke off. She was on the starboard tack, and the waterspout came down upon the weatherbeam, and passed under the stern. At first the ship broke round off seven or eight points, and afterwards kept coming up and breaking off, as the gusts of wind varied their direction, but the wind continued on the starboard side the whole time, and the ship did not alter her position more than a quarter of the circle. It was quite clear, from the peculiar manner in which