which is fixed by screws at both ends, so as to cover the bung, and confine it down securely. For the better preservation of the air-boxes, they should be well painted outside, and to denote their proper place in the boat, they should be numbered 1, 2, 3, 4, &c. to shew the thwarts to which they belong.

3rdly. As to fixing the Air-boxes in the Thwarts.

I would recommend that the clasps should be made of stout sheet copper three inches wide, with four hinges, one at each angle of the bottom of the box and the others at the angles or edges of the thwart to which they belong; going over the thwart, and having an eye and a pin to fasten it. The pin should be secured by a small chain, six inches long. It will be necessary to have two clasps to each box, as described in figure 2, and the clasps should likewise be numbered to denote to which boxes they respectively belong. Fig. 4, represents the end of the air-box, and the end or breadth of the thwart.

Fig. 5, represents the shape and make of the copper clasp, and its four hinges; one at each corner or angle. I place the pins for fastening the clasps in the after part of them, for this reason, that as the sailors sit with their faces towards the stern, they will thereby have a better opportunity of discovering whether any of the pins get loose.

The long air-boxes are to be lashed one over each side of the boat, just low enough to admit a free use of the oars, with their angular ends forward, and are meant to be used when a vessel is obliged to be quitted at sea, either by the accident of fire, or starting a but-end of a plank.

Charmouth, Dorset, February 17, 1817.
To A. AIKIN, ESQ. SEC.

I remain, Sir,
Your very humble Servant,

GABRIEL BRAY.

Reference

Reference to the Engraving of Mr. GABRIEL BRAY'S Life Boat, Plate 21.

FIG. 1, a transverse section of a boat, shewing the method of measuring it for the air-boxes attached under the thwarts.

Fig. 2, shews an air-box fixed under one of the thwarts. Fig. 3, the method of securing the bung of the air-box. Fig. 4, an end view of a thwart, with the air-box beneath it.

Fig. 5. an end view of one of the copper clasps, by which the air-box is fixed in its place.

The foreground shews a boat with the external and internal air-boxes attached. In the distance are represented two boats fitted up according to Captain Bray's plan, labouring in the surf.

The SILVER ISIS MEDAL was this Session voted to Mr. JOSEPH FAREY, of Howland-street, Fitzroy square, for a Double Ball-Cock. The following Communication was received from him, and one of the Cocks is preserved in the Society's Repository.

GENTLEMEN,

HAVING considered the several imperfections in the com mon ball-cock, as applied to water cisterns. I was induced to make some alterations which possess the following properties-first, that the cock will run with its full bore till the cistern is filled to the intended level, and then shuts itself instantly, thereby a great saving of time would be ef

fected,

fected, if the cisterns were fitted with my improvement to the common ball-cocks, since it requires more time to fill the last foot in height of the cistern, than the improved one demands to fill it entirely; and in situations where the water is not clear, and requires time to settle before it is fit for use, it becomes of consequence to fill the cistern as quick as possible, for the water cannot begin to settle till the cock has done running, which is a tedious time in the common ball-cock. Another property of this improvement is, that the cistern may be filled to any required level, by only lengthening or shortening the chain which connects the two balls together, for as the cock remains open till the secondary ball has risen by its buoyancy, so as to bring the chain to a state of tension, and then closes suddenly, the length of the chain determines the height to which the cistern will fill itself. I applied this improvement to a common ball-cock, above twelve months since, and found it to answer the purpose extremely well, possessing all the above mentioned properties, though made quite in a temporary way; it did not cost more than a few pence, being made with one of the stretchers of an umbrella, and a large bung, which were connected to the cock by a small brass chain. I have not found it to require any attention, always' acting very perfectly except during the frost, which every cock must be subject to. Thinking this improvement might be of some service to the public, I have taken the means of making it known through the medium of your useful Society; and am,

Gentlemen,

With the greatest respect,
Your humble Servant,

JOSEPH FAREY.

No. 37, Howland Strect, Fitzroy Square, January 15, 1817.

To A. AIKIN, ESQ. SEC.

Reference