The boat had sailed full of water, without impediment, and being hauled over, and then half filled with water, and released, righted itself immediately.

Here, too, was a Whitby Lifeboat, capable of emptying itself of water in four seconds, by two apertures in the bottom; and a Lifeboat of wood and cork, with gutta percha air-tight compartments, and scupper in the keel for letting out water.

Dyne's Lifeboat was built with diagonal battens laid latticewise, its outer sheathing formed of gutta percha; its buoyancy 350 cubic feet of air, capable of containing 9 tons, and letting off shipped water by 3600 holes; in the convexed bottom were three perforated steadying fins, and between them two tons of water, not one ounce weight to the boat when upright; there were also galvanized springs placed at the stern, to act like railway buffers in collisions; besides a full supply of fusees, rockets, and other lights.

The Lifeboat which gained the prize of 100l. offered by the Duke of Northumberland, was modelled by James Beeching, of Great Yarmouth, and was of whale-boat body: "she would, from her form, both pull and sail well in all weathers; she would have great stability, and be a good sea-boat,; she had moderately small internal capacity for holding water under the level of the thwarts, and ample means for freeing herself readily of any water that might be shipped; she was ballasted by means of water admitted into a well or tank at the bottom, after she was afloat; and by means of raised air-cases at the extremities, a light iron keel, and the absence of mid-ship side air-cases, she would right herself in the event of being upset; thus combining most of the qualities required of a lifeboat."

A Tubular or Double Lifeboat was invented by H. F. Richardson, in 1853: it is formed of two tubes of tinned iron, 40 feet long by two-and-a-half feet in diameter, and tapering at the ends. An iron framework unites the two tubes, which are divided into water-tight compartments, occupied by air-tight bags; the whole is surrounded by a cork fender. Seats for the rowers and passengers are placed above the framework. Colonel Chesney states this boat to have undergone several trials at Plymouth with great success, and he is of opinion that it cannot be upset.

Clarkson's Lifeboat was experimented with at Dover, in 1853 manned by thirteen persons, she was put to sea, was filled by a bucket with water, and set sail. The weight of water

had no effect upon the boat: she maintained her position, the crew then endeavoured by every means to sink her, but in vain. The boat was then pitched off the pier into the sea, but instantaneously righted, and relieved herself of water; she was then turned over keel upwards, but turned into her proper position immediately.

The Expanding Tubular Life-raft, invented by G. F. Barratt, is formed of vulcanized India-rubber tubes, inclosed in canvas cases or nettings, lashed to cross spars, so as to form, when extended, a contrivance for floating on the water, or being rowed like a boat, in safety through a surf or heavy sea. The same inventor has produced a Collapsing Boat, consisting of tubes lashed round a boat-like framework, with three thwarts

which shut up like a purse. The bottom is formed of nettings

to enable the water to have a free course, and the thwarts are kept expanded by means of "moveable fishes."

A noted Lifeboat, called the Mary Anne, belonging to the ports of Hartlepool and Sunderland, is able to right itself immediately, when purposely capsized, particularly when the boat is under sail; the crew received, in four years, the sum of 250/. from the Board of Trade, for saving life, besides salvage money for assisting vessels in distress.

In London has been established the "Royal National Lifeboat Institution," for the purpose of placing their succours upon various stations of our coast, and rewarding services which have saved life from shipwreck. In November, 1866, this institution, since its formation, had contributed to the saving of 15,700 lives from shipwreck. The Society is supported by subscriptions, many in the form of bequests from benevolent persons. Thus, in 1866, Miss Ellen Goodman, of Eversholt, Bedfordshire, left the institution 600l. to pay for a Lifeboat, its equipment, and transporting carriage; Mr. R. Thornton West and Mrs. West gave the whole cost, amounting to 620%. of the Lifeboat station near West Wittering, on the Sussex coast; and in 1867, a lady of Upper Clapton, who had for many years been saving money for the purpose, at her death bequeathed to the institution 450l. with a request that a Lifeboat, named the George and Anne, should be stationed on the Isle of Wight, which request was readily complied with. Bequests of this nature are made under circumstances of touching interest, "which makes the whole world kin."

THE BAROMETER.

HIS instrument is named from two Greek words, signifying two measures of weight, since by it a column of air is weighed against a column of mercury.

The circumstances attending its invention were curiously accidental. The common pump had been well known for many centuries, and its phenomena explained by the wellknown maxim that "Nature abhors a vacuum," why, had never been discovered. The Duke of Florence had employed some pump-makers upon his premises, who found that water would not rise higher than 30 feet, or thereabouts, when the air in the tube was exhausted. In their dilemma they applied to Galileo, who replied that nature had no

power to destroy a vacuum beyond thirty-two feet; for, learned as Galileo was, he understood not the equipoising weight of the atmosphere. At his desire, however, his pupil, Torricelli, investigated the subject.

Evangelista Torricelli was a native of Piancondoli, in Romagna, where he was born in the year 1608. By the care of an uncle, he received an excellent education at the Jesuit School in Faenza, where he became remarkable for his mathematical and scientific attainments. At twenty years of age his uncle sent him to Rome, and he there became intimate with Castelli, then mathematical professor of the college of that city. About this time Galileo was endeavouring to overturn the received

EVANGELISTA TORRICELLI.

doctrine that substances descended in speed according to their natural gravity; and that consequently, if two weights were to descend from a high position, the one which was ten times the weight of the other would reach the ground ten times as soon. Galileo had discovered the pressure of the atmosphere, and was convinced of the principle of its specific gravity, and of the opposition which it occasioned to the effect of the earth's attraction. He went, attended by several officials, to test its validity, and two stones, of very unequal weight, were dropped from the falling tower in Pisa. The truth was evident from the fact that the stones reached the ground nearly at the same moment; but it was in vain that Galileo pointed out that the difference in time of their descent was entirely owing to the unequal resistance of the air. Prejudice had darkened reason too much for conviction to enter into the minds of the persons by whom he was accompanied.

These several experiments, and similar facts which had been educed from them, were not overlooked by Torricelli ; and he published two Tracts, one on the motion of fluids, and the other on machines, which soon obtained the notice of the venerable Galileo, by whom he was invited to Florence. After Galileo's death the Duke of Florence gave Torricelli the chair of Mathematics in the Academy; and he thus became his friend's successor, when he was about 39 years of age.

To return to the invention of the Barometer. Torricelli first imagined that the weight of the atmosphere might be the counterpoise to the 32 feet of water; or, at least, he was the first whom we know to have applied himself to try this supposition by experiment. He saw that if it be a weight of air which counterpoises the 32 feet of water, it must follow that by the substituting of mercury instead of water, the height of the column necessary to counterpoise the weight of air would be reduced in the proportion in which mercury was heavier than water. For instance, that if mercury be fourteen times heavier than water, bulk for bulk, the fourteenth part of thirty-two feet, or about two feet four inches, would supply the place and produce the effect of the water. He accordingly filled a tube more than three feet long, and open at one end only, with mercury, and then stopping the open end with a finger, he placed the tube in an open vessel of mercury, with the open end downwards. On removing the finger, the mercury in the tube sank until it stood in the tube at about

28. inches higher than the mercury in the vessel. Having marked the specific gravity of the mercury, the weight of the column of air between the mercury and the top of the tube became of course apparent, from the respective proportions of air and mercury and the whole length of the tube. Torricelli thus constructed what is at this time considered the best form of barometer. It should be stated that in 1601, that is, 12 years before Torricelli's observations, Descartes, the French philosopher, had made the same observation, although he does not appear to have turned it to any account.

Torricelli died in 1647, leaving his great discovery not quite complete; for, though he had made it apparent that the weight of the water and the mercury was a counterpoise of something, most probably of a weight of air, the latter was not quite certain. The invention, however, was taken up by Pascal, Mersenne, and others in France; and by Boyle, in England, the latter, by means of the air-pump, being enabled to subject air of different degrees of density, to the test of the barometer. Pascal, who had repeated Torricelli's experiments at Rouen, before more than 500 persons, and obtained the same results as Torricelli, did the same; and assuming that the mercury in the Torricellian tube was suspended by the weight or pressure of the air, he suggested that it would necessarily fall in ascending a higher mountain, by diminution of the superincumbent column of air. At his request, his relative, M. Perrier, tried the barometer at the summit and base of the mountain in Puy de Dôme, in Auvergne; and the result was that the mercury, which at the base stood 26 inches (French), was only 23 inches at the summit; the mountain being between three and four thousand feet above the level of the sea. A like result was afterwards ascertained by Pascal himself; and he also discovered that the same rule prevailed and was very sensibly shown, in the ascent of a private house and a churchtower in Paris; thus establishing the theory of atmospheric pressure beyond dispute, and that the weight of a column of air was equal to that of a column of mercury about twenty-eight inches high, that is, a pressure of about fifteen pounds on a square inch.

The discovery was, however, at first much misconceived, and even disputed, until it was seen by a glaring instance, that the maintenance of the mercury in the tube was the effect of a perfectly definite external cause; whilst its fluctuations, from