under the old system, was subject to great friction and constant derangement, and was affected by changes of weather, and the former action was often so stiff and capricious that the organist found his duty extremely laborious; while the organ-builder was often called in to make expensive repairs.

Under these circumstances a difficult problem was to be solved. Any improvement on the old action must be simple in itself and easily kept in order, and must of course be free from the effects of friction or atmospheric changes, so as to insure a light touch on the keys, and an instantaneous response from the organ-pipes at any practical distance from the key-board. The new electric organ action, it is believed, will fully comply with all those requirements. When actually and practically applied it is found that the touch is always as light as that of the piano, and the action is literally as quick as lightning, while any one of ordinary intelligence having charge of the building in which the organ may stand can keep it in running order, so far as the battery, which is the motive power, is concerned. It is based, in a word, on the well-known principles of the electric telegraph, as well as the electric burglar alarm, the hotel annunciators, the electric clocks and police telegraphs; all of which are in successful daily operation. The new organ, now building by Messrs. Hall, Labagh, & Co., is intended to be a powerful instrument, considering its size, of about 9 stops, including the pedal bass; and, although necessarily limited by want of space, will fairly exhibit the principles involved.

The key-board will be detached from the organ at a distance of about 25 feet, though it might as well be removed to the distance of 25 miles, excepting for the necessity of the organist hearing his own performance, since we know, from recent scientific investigations, that the electric current will travel a mile in a fraction of a second. The only connection between the key-board and the body of the organ is a bundle or rope of flexible, insulated copper wires, which may be carried in any direction without injury, and there is no pull or strain on these wires, as they are merely the passive means of conducting the electric current.

The source of the electric current is an ordinary "single fluid" battery, placed in any convenient position, composed of a series of jars containing a mixture of sulphuric acid and water, and in each jar is suspended a plate of carbon, in company with_two plates of zinc, connected in the usual way by copper wires. From one end of this series of jars, a copper wire proceeds to the keyboard; and, if we take the case of a single key, for example, when it is pressed down by the finger of the player, we shall find this wire so connected that it forms an unbroken circuit and proceeds from the key-board onward to the body of the organ, where it is coiled around a soft piece of iron shaped like a horse-shoe, and thence returns from the organ to the other end of the battery. When a wire is connected with both poles or ends of a battery the current passes, and the piece of soft iron becomes a powerful magnet; but the moment the current is broken, by disconnecting the copper wire, there is an instant loss of power. When the key

of the organ is not touched, the wire is not connected and the current does not pass; but on pressing down the key a metallic contact is formed, the electricity darts along the circuit, and the electro-magnet, becoming at once excited, pulls down the pallet, or opens the valve in the wind-chest, admitting air to the organpipes and with lightning speed causing them to speak.

The couplers are applied and the stops drawn upon the same principle. It has been stated that a more expensive and less simple arrangement has been successfully applied in England and

France.

THE AMERICAN STEREOSCOPE.

The following is an abstract of a paper in the "Philadelphia Photographer" of January, 1869, by Dr. Oliver Wendell Holmes, the inventor of the American stereoscope:

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"The British Journal of Photography' had two articles lately, the first dated Oct. 16, 1868, and the second the following week, relating to the American Stereoscope,' as I see it is called in England. The figure they give in the second of these papers, though not of the best model, yet shows that the instrument referred to is a copy of the one which was first made in Boston, and of which I shaped the primitive pattern with my own hands.

"This simple stereoscope was not constructed by accident, but was the carrying out of a plan to reduce the instrument to its simplest terms. Two lenses were necessary, and a frame to hold them. I procured two of the best quality, and cut a square frame for them out of a solid piece of wood. A strip of wood at right angles to this was required to hold the pictures. I shaped one, narrow in the middle, broad at both ends; at one end to support the lenses, at the other to hold the stereographs, which were inserted in slots cut with a saw at different distances. A partition was necessary, which I made short, but wedge-shaped, widening as it receded from the eye. A handle was indispensable, and I made a small brad-awl answer the purpose, taking care that it was placed so far back as to give the proper balance to the instrument. A hood for the eyes was needed, for comfort, at least, and I fitted one, cut out of pasteboard, to my own forehead. This primeval machine, parent of the multitudes I see all around me, is in my left hand as I write, and I have just tried it, and found it excellent. I contrived another form of stereoscope like the first, but with a gilded, slanting diaphragm with two oval openings, so that the effect was that of seeing the stereograph through a round window, with a golden light on it reflected from the slanting surface of the diaphragm. This I showed also to various dealers, as a form of stereoscope that might please certain exceptional amateurs. Some time after showing it, I found the so-called 'Bellevue' stereoscope in the market, which I had good reason to consider an imperfect attempt at a reproduction of the pattern I had somewhat freely exhibited. The effect referred to, of cutting off all the borderings of the picture, and throwing (by means of the slanted and gilded diaphragm) a Claude Lor

raine light on the stereograph, is, in many cases, very striking, but, for common use, the simple form is preferable."

PRACTICAL APPLICATION OF SENSITIVE FLAMES.

An apparatus has been invented by Barrett for making practical use of sensitive flames. It consists of two perpendicular copper rods, one of which, on its upper end, holds a metallic ribbon, which is composed of thin leaves of gold, silver, or platinum, welded together. Such a ribbon expands unequally under the influence of heat; it bends toward one side, and, in doing so, comes in contact with a fine platinum wire attached to a galvanic battery. As soon as the poles of the battery are closed, a bell begins to ring. The working of the apparatus is as follows:

"A sensitive flame is lighted about 10 inches from the metallic ribbon. This burns quietly so long as there is no noise, but a shrill whistle, or any unusual disturbance, will cause it to diminish one half in length, and to spread out wide in the middle, like the wings of a bird. It thus heats the metallic ribbon, which expands unequally, and occasions the contact of the poles of the battery, which rings a bell."

Such a light as this in a banking-house would betray to the watchman the noise of robbery, and the inventor proposes to use it as a species of burglar alarm. As sound can be transmitted in water 4 times as rapidly as in the air, it is also suggested to employ this method on shipboard, to make known the approach of a vessel in time of a fog.

There is probably the germ of curious applications of sensitive flames in Barrett's invention, and it would not be surprising to hear of its use in war, to warn a sentinel of the approach of the enemy, or of its application to a new species of telegraphy.

ELECTRIC BEACONS.

Thomas Stevenson, C.E., Edinburgh, recently conducted an experiment at Granton, with the view of showing the practicability of illuminating beacons and buoys at sea with the electric light produced by means of a battery on shore. A submarine cable, fully half a mile in length, was laid between the east breakwater of Granton Harbor and the chair pier at Trinity. The operator occupied a station near the centre of the breakwater, and the light was shown at the point of the pier in front of an ordinary light-house reflector, producing a most brilliant flash. The flashes were emitted with great rapidity; as many as 500 can be transmitted in a minute, but the machine can be regulated so as to send one every second, or at any other desired interval. The experiment gave entire satisfaction.

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PORTABLE ILLUMINATIONS.

Mr. Alvergniat, a French electrician, has made an improvement first suggested to him when using the tubes invented by Giessler, which are cylinders or bulbs of glass filled with rarefied gas that becomes luminous in the dark when a current of electricity is passed through it. The improvement consists in filling a glass cylinder or phial, hermetically sealed, with a substance which becomes phosphorescent by the action of the frictional or static electricity. A tube of this kind may be of some service to those on night duty; for all that is requisite to produce a feeble and ephemeral light is to rub the tube briskly with a silk handkerchief.

WARMING CHURCHES BY GAS.

The following method has been patented in England: A brick chamber is made beneath the floor of the building, and a grating is placed over it to allow of the passage of hot air. Beneath this chamber an air-flue in connection with the flooring, and covered with an iron grating, is introduced. By these means a current of air is made to pass into the building, and this air is brought into contact with a ring gas-burner, which is supplied by an ordinary main by means of a spanner, by which the amount of heat can be regulated. Underneath this ring-burner is placed a sınall cistern made of fire-clay, filled with water; the heat from the gas-burner acts upon the water, steam arises, and this is passed through pumice stone contained in a cylinder above the cistern; the use of this vapor is to moisten the atmosphere contained in the reservoir. Around this is a circular cylinder made of fireclay, to contain heat. The whole is covered with a dome of fireclay. This dome is worked by a lever for the purpose of lighting the ring-burner. By these arrangements, it is said that a pure heat, free from smell or smoke, is obtained, and that with a very small consumption of gas.

GAS FOR LIGHT-HOUSES.

A series of letters and reports sent to the Commissioners of Light-houses and the Board of Trade has resulted in a request being made to Professor Tyndall, by the latter body, that he would report upon the proposal to substitute gas for oil as an illuminating power for light-houses, as illustrated in the light-houses of Howth Baily and Wicklow Head. Various experiments were made at Howth Baily, and Professor Tyndall says that the superiority of the gas over the oil flame is rendered very conspicuous by these experiments. The 28-jet-burner possesses two and one half times, the 48-jet-burner 44 times, the 68-jet-burner 73 times, the 88-jet-burner 9 times, and the 108-jet-burner 13 times the illuminating power of the 4-wick flame. The oil lamp with which the gas flame was compared was the most perfect one em

ployed by the Commissioners of Irish Lights. Further experiments were also made, and it appeared that the whole of the gaslighting apparatus was entirely under the control of the keeper, and that no damage was likely to arise from it. The 28-jet gasburner, when seen from a position some miles off, appeared to be very nearly upon an equality with the oil lamps, but when muffled to represent a fog it had a slight advantage. Of course with the brighter jet-burners a great improvement was apparent, and before the 108-jet-burner the oil lamp grew quite pale. By the adoption of a system of gas-lighting a great saving in cost would be effected; but such a system would not be possible on rock light-houses. Professor Tyndall recommends the encouragement of this system of illumination in Ireland. He was assisted in his investigations by Mr. Valentin, Captain Roberts, and Mr. Wigham. - Brit. Trade Journal.

DISPOSITION OF GAS-BURNERS.

Much of the economy and effect of gaslight, says the " Gaslight Journal," depends upon the arrangement of gas-burners in relation to each other, to the surroundings of furniture, height of ceilings, distance, and angles of walls, hangings, etc.

The general practice in this country and in Europe, of disposing burners in chandeliers in the centre of rooms, although pleasing to the eye in its artistic effect, simply as an ornament to the room, is far from being the most philosophical manner to obtain the best effect from the light.

The diffusion of light, in its effects, is materially modified by the laws of reflection and refraction.

Light decreases in intensity in proportion to the square of the distance from the burner or point of illumination. This is a general rule; but in a room with four white walls and a ceiling, the reflection of the light upon itself, as it were, will apparently modify the rule.

Shadows have much to do in the effective and satisfactory lighting of any hall or room. Hence it is that a single light, or a centre-piece, or nucleus of lights as represented by a chandelier, is objectionable, because your shadow will appear in any part of the room opposite to the light, and is more or less inconvenient in proportion as it differs in that respect from daylight, which is so diffused as to avoid this evil except in peculiar conditions.

Now, in view of these suggestions, is it not apparent that the proper and most efficient position for gas-burners is at the different sides, or, better, the different angles of a room? Then the intensity of light will be more uniform in every part of the room, no shadows will be formed, and the reflective action of the walls will be most effective. These reflections will show the folly of using bracket-lights at one side only of a room, where shadows fall in every direction it is possible to move from it, and with increased intensity as you go, until the gloom of the opposite side brings you back like a moth, to be blinded by the glare of the immediate