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THOMAS STEELE, M. A. of Magdalen College, Cambridge, Esq. has obtained a patent for his Invention of certain Improvements in the Construction of Diving Bells, or Apparatus for Diving under Water.

THESE improvements consist in combining, what the patentee calls a bell of observation, with the ordinary working bell; and in connecting with this latter an air chamber above the surface of the water, by which means a communication is formed, that enables the persons above and below, to converse together, so as to give and receive orders for shifting the situation of the bell, to lower the grappling-tackle, draw up goods, &c. The engraving represents a section of the improved bell, the part marked a, is the ordinary bell, open at bottom, in which the workinen act, subject to the pressure of the condensed air, as usual, when the bell is under water; b, is a close compartment or bell of observation, with glass windows, which has a communication with the atmosphere above, by two pipes, c and d.

Before the bell is lowered, the director of the work passes through the man hole, g, into the bell of observation, b, and having closed the man hole air-tight, the bell is allowed to descend, by means of the slinging chain, with the director in the compartment, b, and the workmen in the open bell, a. When the bell has reached the bottom, the workmen will be subject to the inconvenience of the pressure of the condensed air in the working bell, a, but in the close compartment, b, the director will be enabled to move about in a common atmosphere, communicated through the pipes, c, and d, from above.

The director looking out through the windows placed in the sides, the top and the bottom of the bell of observation, seeing the situation of articles lying near the bell, writes upon a slate or other tablet, and holding it up at the window which looks into the working bell, instructs the workmen how to proceed; or if any communication is required to be made with the persons above, he speaks through one of the pipes.

Should it be found necessary to give instructions at any length to the workmen, a paper may be passed through the tube f, in the side of the compartment b, by opening the inner cock, and then closing it, when the workmen opening the outer cock, takes the paper out of the tube, and closes the cock again. If it should be found necessary for the purpose of refreshing the air or ventilating the close chamber, b, the cock, g, may be opened, and a supply of air taken from the open bell, which is restored by the forcing pump above, through the pipe, h. A small aperture, i, is made through the lower part of the compartment, b, to be furnished with an air-tight sleeve, for the observer to put his arm through, if necessary,

In case one of the workmen should find it necessary to quit the bell, and proceed some distance under water, to gain access to some part of a wreck, which is at a small distance from the bell, such, for instance, as to enter one of the port holes of a ship, he must be furnished with a water-tight hood, enclosing his head; and for the purpose of respiration, this hood must have an air-pipe, forming a communication with the interior of the working bell: such a contrivance is, however, not claimed as new. The improvement therefore proposed, is to adopt a second pipe to the hood, communicating with the chamber of observation, b, so as to allow the workmen to converse with the director, and thereby facilitate the business, the pipes being furnished with suitable stop cocks.

The upper part of the figure represents an improvement proposed to be adapted to an ordinary working diving bell; a, is the ordinary bell, h, is the pipe through which condensed air is to be pumped; c, are the chains by which the bell is slung and lowered into the water from a vessel above. To this bell is attached a pipe, k, communicating with an air-tight chamber, on the deck of the vessel, or any other couvenient place above the water. In this chamber a person is placed, who will, of course, suffer under the same pressure of condensed air that those in the bell are subject to; but the

advantage to those in the bell will be, that they are enabled to converse through the pipe with the person above; who, from his situation, can communicate instruction to such persons as are near him. This chamber, has another air-tight chamber, connected with it, into which the person may get through a man hole, and having closed the man hole, so as to render the chamber, still air-tight, he may then open the other chamber, and pass out.

The patentee proposes, as an addition to the last described apparatus, to form a flexible tube of water-proof canvas, or other water-proof material, sufficiently large for a man to pass through; this tube is to be distended by a series of hoops, and being inserted into an opening in the air chamber above, and made fast and airtight thereto, the tube is to be made fast in like manner to an opening in the working bell, which has been secured by grapples or anchors, for the purpose of forming a ready communication, by means of a rope ladder, between the deck of the ship and the diving bell below.

In order to throw light into the port holes of vessels, or other inaccessible parts, for the purpose of examining between the decks of a wreck, the patentee proposes to construct an optical instrument connected with the diving bell, which shall enable him, by means of a concave reflector and lenses, to throw a strong light from a lamp in any oblique direction. This is not claimed under the present patent, and is not, therefore, particularly described. In addition to what is above stated, a correspondent has suggested the following. The bell is

1st. Far more safe-for instead of depending, as before, upon a system of signals, by strokes of a hammer,

water, at any depth whatever, at which a diving hell can be worked, without being subjected to endure, even for a moment, the pressure of air in a state of condensation, and at the same time holding constant conversation with the persons above.

The construction of Mr. Steele's patent head-piece, is another application of his principle, for the purpose, not only of detaching men from the bell, but of enabling them to work within the common diving bell, (filled, of course, with condensed air) at depths much greater than can be endured at present.

We are informed, that a bell has been just made by Mr. Penn, of Blackheath-hill, in which, it is said, Mr. S. intends to make a descent in a short time.

An instrument has been in use for the purpose of viewing objects under water; but Mr. S. by an application of optical principles, has shown the construction of an instrument, not only for viewing them, but for their stronger illumination.

As a subordinate improvement, Mr. Steele, who has had practical experience, recommends the addition of a rim of hemp, or some other tough material, round the bottom of the bell, to diminish the effect of impact, on rocky bottoms, in ground swells, &c. when preparing for blasting, quarrying, &c. &c.

This, the inventor " hopes may become a very powerful instrument in carrying on submarine operations, as it affords a theory, which he ventures to predict, will in time be reduced to practice, of a mode of sending down from the deck to the bottom of the sea, by the same means by which they ascend from the deck to the mast head."

SING FROM ITS ROTATION.

2ndly. Far more effective-As by the construction of Mr. Steele's bell, the bell work can be carried on under the immediate inspection of the directing engineer himself, who can now remain for an indefinite time under

(Concluded from p. 147, No. 150.)

My first object was to find what points on the plate must coincide with the limb, in order that the plate, when its centre was on the meridian, should cause no deviation in

I considered as the effect produced on the needle by the rotation of the plate in opposite directions. Repeating these in a variety of positions, I found that when the centre of the plate was in the magnetic meridian, its plane being always a tangent to the sphere circumscribed about the centre of the needle, the deviation of the needle caused by the rotation of the plate in its plane, was the greatest when the centre of the plate was in the equator, and that it decreased from there towards the poles, where it was nothing;* that when its centre was on the equator, this deviation was the greatest when the centre of the plate was on the meridian, or in longitude 90°, and decreased to nothing in the east and west points, or when the longitude of the plate was 0° or 180°; and that when the centre of the plate was in the secondary both to the equator and meridian, the rotation of the plate, whatever might be its latitude, caused no deviation of the needle. In these experiments, the plate which I made use of was a circular one 17.88 inches in diameter, and 099 inch in thickness, weighing 112 oz. The further I had pursued this inquiry, the more I was disposed to attribute the effects I have mentioned to a general magnetic action, arising in a peculiar manner from the rotation of the iron; and my next experiments were with a view of ascertaining how far this idea was correct. As similar results might not be obtained with any other plate, I next made use of a plate 12·13 inches in diameter and 075 inch in thickness, weighing 38.75 oz. and with it obtained results precisely of the same nature, though considerably less in quantity. Another objec

I should here mention, that, from the nature of my instrument, I could not make observations at the north pole; but as the results, as far as I could observe, were of the same nature on this

side of the equator as on the south side, I think I am warranted in concluding, that at the north pole the results would likewise be of the same nature as at the south pole.

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tion which occurred to me was this→→→ that the iron being evidently slightly polarized in particular points, the effect might be supposed to arise from an impulse given to the needle by the motion of these points in a particular direction, and that the directive power of the needle not immediately overcoming the slight friction on the pivot, a deviation might thus arise from the rotation of the plate. Had this, however, been the cause of the deviations, I should have expected that, when the centre of the plate was in the meridian, the greatest effect would be produced with the plate parallel to the horizon, and its centre vertical to that of the needle; but I had seen that the greatest deviation took place when the centre of the plate was in the equator, its plane being perpendicular to it; and the deviation arising from the rotation, when the plate was parallel to the horizon, was not a fifth of the deviation when the plate was perpendicular to that plane. Besides it was manifest that if this were the cause, any other impulse would have a similar effect. I therefore made the needle revolve first in one direction, and then in that opposite, by means of a small bar-magnet, and invariably found that it settled at the same point, in whichever direction the impulse was first given, and the results obtained by the rotation of the plate were in these cases of the same nature as before. It was also evident, that if the deviations I have mentioned arose from this circumstance, the needle being agitated after any particular point of the plate was brought to the limb of the instrument, it ought to settle in the same direction, whether that point were brought into this position by revolving from east to west or from west to east; but this, except in the cases I have mentioned, where the rotation produced no deviation, was not found to take place. In order wholly to obviate this objecafter any point had been brought to tion, in all my future experiments, the limb of the instrument, I agitated the needle, and let it settle before I noted the deviation.