IN our August Number we inserted a Paper by ADMIRAL RIDER on the great advantage that would accrue if the ham- mocks in ships of -war could be made to serve as life-buoys, in the event of a ship suddenly foundering; more especially as in future naval wars it is probable that such catastrophes will be of much more frequent occurrence than formerly, con- sequent on the general introduction of torpedoes and of steam-rams.

We are now able to state that the result of experiments since made has proved that, by the adoption, of a cork mattress, a naval hammock can be readily and quickly converted into an efficient life- buoy which will support one man buoy- antly, with his breast and shoulders well above the water's surface, without de- priving him of the power of locomotion, whilst it would support three men in an upright position, with their heads and faces above water.

As such mattresses can also be made much more cheaply than those stuffed with hair, and are as comfortable to sleep on, it would seem that there need be no impediment to their general use in the Royal Navy.

ADMIRAL RYDER, in introducing them to the Admiralty, has suggested that the whole system of supply should be changed, and that instead of each seaman having to pay 10s. &d. for his mattress on its being supplied to him, and its then be- coming his own property, that the Government should provide each man with a cork mattress, as well as with the ham- mock hitherto supplied, and that both should be returned into store together on his ship being paid off. We think this would be a great improvement on the present system; but if it should be rejected on account of the large expense which it would occasion, a small sum might be charged to each man for the use of a Government mattress, the whole cost of which, as manufactured by Messrs. BIRT, of Dock Street, London, the well- known manufacturers of Life-saving Apparatus to the Board of Trade, and the NATIONAL LIFE-BOAT INSTITUTION, would not exceed 5s. 6d. each when new.

In the remarks we made on this subject in our August Number, we stated that we believed the most effectual mode of using such beds as life-buoys would be found to be by bending the hammock as lashed tip and stowed in the netting, bringing the two ends together and securing them by the ordinary laniards, by which the ham- mocks are hung up when slept in, thus forming a large life-buoy, shaped some- what like a horse-collar. Since then, j experiment has proved that such would be the best mode of adopting them, with the exception of not bringing the ends close together, but leaving them about 18 inches apart, when the form will be that of a horse-shoe, as shown in Fig. 1.

rig. i.

Haniinod* folded ready for use as a Life-preserver.

On a catastrophe occurring, each man would then take a hammock from the netting where they were stowed, and bending it backwards, so as to tighten the lashing, would secure the ends by the clues and laniards, and jumping over- board with it under his arms, he would be able to swim with, it clear of the ship, and to support himself on it until help should arrive.

The sketch (Fig. 2) shows the manner in which a man would support and propel himself? -with the aid oi the hammock- buoy:—

FiJ. 2.

193 Man Swimming with Hammock.

Another mode in which the hammocks might be used advantageously, and which has also been proved by experiment, is by lashing two hammocks together at the ends, about 20 inches apart, so that two, or even three persons, placing themselves between them, with one arm over each hammock, and facing the same end, could strike out with their legs as in swimming, and thus propel themselves through the water, as shown in the sketch, Fig. 3 :— Fig. 3.

Two men Swimming between two Hammocks.

This mode of using the hammocks might, ] under some circumstances, be of great ! advantage, as two men might in this ! manner proceed several miles through the I water in a few hours, and might even convey intelligence of a catastrophe to the nearest port or to a distant vessel, where assistance might be obtained.

It is not, however, contemplated to confine the use of cork mattresses to the Royal Navy, for they might undoubtedly be made instrumental to the saving of many lives in merchant vessels where those on board are unprovided with life- belts. Since, however, merchant seamen are not usually provided with hammocks, but sleep in berths, or bed-places, a different arrangement has necessarily to be adopted. Messrs. BIRT have therefore designed and patented a special form of mattress, which can be so secured round the body, close under the arms, as to form a life-belt.

To effect this the mattress is divided, longitudinally, into two distinct parts, but united by the linen covering on one side, so that the two parts will fold back, as on a hinge, and thus be doubled and reduced to half the original width.

The sketches (Figs. 4 to 9) will give a correct idea of their character, and of the manner in which they would be worn:— Fig. 4.

Mattress folded ready for use as a Life-preserver.

Fi?. 6.

Section of Mattress—end View.

Fig. 1, Front view of Mattress when on.

Back view of Mattress when on.

Fig. 9.

Man swimming with Mattress.

Cushions for the deck and cabin scats in passenger-vessels, yachts, and pleasure-boats of all kinds, are also made in the same manner, each'cushion being of the width of one fold of a mat- j tress.

These mattresses and cushions have only to be seen to convince any one of their fitness for the purpose for which they are intended; and we feel con- fident that their general adoption for the purposes above indicated would lead to the saving of a large number of lives.

In proof of their ample buoyancy, it may be stated that the buoyancy of a single mattress is equivalent to sixty pounds, as it will float an iron weight of that amount; whilst the buoyancy'of the best description of cork life-belts, or life- jackets, as provided to the crews of Life- boats, is only from twenty-three to twenty- seven pounds.

The cork with which they are filled is ground or granulated by machinery, and after the dust is removed the grains are of small size, which gives the mat- • tresses a soft and elastic surface. Eight pieces are then inserted to prevent the cork from shifting. It also absorbs so ! little water that a mattress which has i been immersed for twenty-four hours has ' at the end of that time lost but little of its buoyancy.

A great inducement to adopt these mattresses would also be found in the fact, that even the most expensive of them, namely, those costing 11s. 6d. each, cost less than half of what they would do if made of horsehair. Those, with the commonest description of covering, can be had for 7s. Qd. each; and their buoyancy, and therefore their practical utility as life- buoys, is the same as that of the more expensive kinds.

Cork mattresses were made many years ago; they were afterwards, in 1855, pa- tented by Mr. RITCHIE for army purposes, and later were made by Messrs. PELLEW and Co.; but the patent has since expired, and those now manufactured and patented by Messrs. BIRT are a great improvement on them.

In conclusion, we desire to call the attention of shipowners and masters of vessels to the fact that instances are frequently occurring, in cases of shipwreck, of men provided with life-belts being saved, when those without them have been drowned; and we would urge on every one going to sea the desirability of their providing themselves, or of their being provided, with these cork mattresses, or with good cork life-belts.