nium-coated wires through which the electric current is passing, a sheet of paper saturated with phenolphthalein, glycerine, and alcohol.

An allied discovery, though by a totally different method, accomplishing the distant reproduction, in line engraving, of pictures, was described last year-the electroartograph, invented by Mr. N. S. Amstutz of Cleveland, O. (Vol. 5, p. 454).

An Automatic Telephone Exchange.-Under the present system of telephony, so much space is needed for the various stations and complicated electrical arrangements for establishing contacts and connections, and so large a staff is required for efficient working, that the capacity of a single exchange is practically limited to a few hundred subscribers. The Apostoloff automatic telephone is an invention whereby, it is claimed, any person can, without the assistance of a "central" attendant, put himself directly into communication with any other of even as many as 10,000 subscribers. The device is described thus:

In the central station each subscriber is represented by a piece of apparatus contained in a box a few inches high, which is connected by an ordinary metallic circuit to the telephone in his house or office. Ordinary telephones are used with the addition of a small piece of apparatus termed a "transmitter" or "manipulator." The face of this transmitter is pierced with three little windows or apertures, in two of which numerals appear and in the third certain service indications. Suppose a subscriber wishes to speak with No. 1,795.. He presses a button under the left-hand aperture until the numerals 17 appear. He then does the same to a button under the right-hand window until 95 appears. These two operations have produced corresponding movements in the instrument that represents him at the central station. The positive currents sent by the left-hand button have passed through a polarized relay and caused a local battery to send seventeen successive currents through an electro-magnet which has moved a travelling switch step by step past sixteen contacts, each representing a group of 100 subscribers, until it has stopped on the seventeenth of the row. The negative currents have in the same way moved a second travelling switch till it is in connection with the ninety-fifth contact of the other row. The subscriber now presses another button, which causes the words Ring up" to appear in the middle aperture. At the same time, by an ingenious electrical arrangement, the electromagnets that actuate the travelling switches are cut out and the circuit is completed to 1,795. He now rings up in the usual way, and in return 1,795, if he wishes to speak, presses one of his buttons and* causes the words " Are you there?" to appear in both transmitters. Conversation is now possible. After finishing, both subscribers touch a button marked Finish," whereupon the numbers in the windows fly back to zero, "Off" appears in the middle window, the travelling switches in the apparatus at the central station return to their initial position, and the whole apparatus is ready to be used again.

It is claimed that this invention is easily and inexpen

sively adaptable to existing telephone systems having complete metallic circuits, that it does away with the heavy expenses of large central and branch exchanges and of the numerous staff they necessitate, that it means a great saving of time and does not leave subscribers at the mercy of the attendants at the various exchanges, that it insures absolute secrecy in communications.

Astronomy. The periodical comet discovered by Professor Brooks at Geneva, N. Y., in July, 1889, was again seen on June 19 by M. Javelle of the Observatory of Nice, France.

It is sometimes known as Brooks' multiple comet, owing to being composed of a parent body, as it were, preceded by four small attendant comets, whose separate existence is visible only through the most powerful telescopes. Its present period of revolution around the sun is about seven years. Computing backward, however, it was found that in 1886, three years before its discovery by Professor Brooks, it had come within the sphere of Jupiter's attraction, and that to this fact was due its present orbit and seven-year period: its former period was of nearly thirty years' duration.

It is believed that during this encounter of Jupiter and the comet, the material for the fifth satellite of Jupiter, discovered by Barnard in 1892 (Vol. 2, p. 421), was secured-captured from the comet by Jupiter's superior attraction.

Professor T. J. J. Lee of the Lowell Observatory, Flagstaff, Ariz., announced in September that he had rediscovered the lost companion of Sirius, a so-called "dark" or faintly luminous star, which had not been seen since 1890, when it was observed with the Lick telescope. The satellite is about half as large as Sirius, and just about the size of our sun. It appears to be a burned-out world; but we are still ignorant of the cause of its darkness in remark-able contrast with the brilliancy of Sirius.

Aerial Navigation.-Numerous attempts at a solution of the problem of air-flight have been reported of late.

At Portsmouth, N. H., August 20, Mr. Charles H. Lamson, a Portland jeweller, demonstrated the possibility of making kite-flying an adjunct to meteorology and aëronautics. By means of a large cellular or box kite, which is described as "a radical modification of the Hargraves box or cell kite," he succeeded in lifting to a height of 600 feet a weight of 150 pounds, designed to represent a man. When the kite had reached that altitude, the rope parted, and the apparatus came down, but so gently that had a living man been carried by it, he would not have been hurt.

The cells or boxes of the kite are hinged on a pivot near the centre, so that their angle of inclination to the wind and to one another can be changed at will. On the space between the two cells of the kite is where it is purposed to place the man who goes aloft with the kite. The passenger, by manipulating a lever, can keep the air-ship on an even keel, make it rise or fall, and direct its course in

coming down. Lateral steering can be accomplished by changing the weight to either side of the centre, the aërial vessel then turning toward the side where the weight is greatest.

A flying machine invented by Professor Octave Chanute, ex-president of the American Society of Engineers, was tried with some success in the early part of September, at a point on the southern shore of Lake Michigan, in northern Indiana.

The machine is modeled on the bird principle of soaring against the wind by means of several aëroplanes. Attached for purposes of steering, is a broad, movable tail-piece called a Herring regulator, so named after its inventor, Mr. A. M. Herring, an assistant to Professor Chanute. As in the case of the invention of Herr Lilienthal, whose recent accidental death during an experiment with his machine was a serious loss to science (see Necrology), the "soaring" is accomplished by running rapidly a short distance down an inclined plane and then leaping into the air.

At the Berlin Industrial Exhibition, August 28 and 29, there was exhibited a new dirigible balloon designed by Dr. Wolfert.

The device consists of an elliptically shaped gas bag, over thirty yards long, with its longer axis horizontal, from which is suspended a bamboo basket five yards long, so fastened that neither part of the balloon can have separate movement. The motive power is an eight horse power engine driving a double-bladed propeller, having a diameter of about three yards. It is placed in front of the basket, while below the car is another propeller of the same dimensions, for upward and downward movement. These propellers make 500 revolutions per minute.

The balloon rose to the height of about sixty-five feet, and was propelled in all directions, even against the wind.

An application of the principle of bicycle propulsion has been made to balloon navigation by J. C. Ryder, a young man of Richmond Hill, L. I.

The body of the balloon is a cone shaped gas bag, with the bicycle apparatus suspended below. The pedals, acting on a high-geared sprocket wheel and chain, set aluminium paddles revolving. Just how this "flying bicycle" is steered, is not made clear. It is said that Mr. Ryder has actually propelled himself seven miles in the teeth of a wind, at an altitude of 200 feet.

By means of cameras attached to kites, Mr. W. A. Eddy has succeeded in taking mid-air photographs of the city of Boston and other places. Among the advantages of the mid-air camera, it is claimed, will be the power of detecting the approach of an enemy in time of war, or the approach of a man-of-war long before its hull is visible above the horizon.

The Bazin Roller Ship.-A unique attempt in shipbuilding, to solve the problem of giving greatly in

creased speed without proportionate increase in expenditure of energy, is that of M. Ernest Bazin, a well-known French marine engineer, whose roller ship, named after himself, was launched on August 19, at the Cail dockyards on the Seine, at St. Denis.

The strange craft, of about 280 tons' burden, comprises, in a word, a rectangular iron frame or platform (carrying deck houses), about 120 feet long and forty feet wide, mounted on six hollow, watertight, lenticular rollers (three on each side), each about thirty nine feet in diameter and twelve feet in thickness, submerged about onethird, revolving vertically in the water with a speed proportioned to the forward motion of the vessel, which is produced by a screw propeller actuated by a 550 horse-power engine.

The rollers are connected in pairs, each pair being actuated by a fifty horse-power engine. It is hoped that by the use of the rollers the friction of the water will be reduced to a minimum, it being the theory of the inventor that the boat should roll over the water without cutting through it. The strain is not longitudinal but vertical, and the inventor hopes that the "bite" of the roller on the water will be analogous to that of a car wheel on a sanded rail, only, of course, allowance being made for the mobility of the water.

The principle of the new boat may be understood by making a hollow lens-shaped roller out of tin, so that it will somewhat resemble two saucers fastened together. If this disk be plunged into the water and pushed forward, it will go ahead for some distance before being stopped by the resistance of the water; but if, before it is pushed along the water, it is given a sharp rotary movement, it will be found that the disk will saw the water instead of beating it, and that it will cover several times the distance that it did when it was simply pushed.

Besides greater speed, with lessened coal consumption and lowered freight rates, other advantages are claimed for craft built on the new model:-greater stability, and therefore less liability to seasickness on the part of the passengers; better ventilation; more sunlight; and practical impossibility of sinking, the uninjured rollers, in case of collision or other mishap, serving as air-tight compartments to prevent foundering. Admiral Coulombeaud, a high French naval authority, has computed that only one-twenty-seventh of the power required to drive an ordinary boat is needed for a Bazin craft of the same size and speed.

Serum Treatment of Leprosy.-That leprosy is curable seems to be borne out by a recent report to the National Academy of Medicine, Bogota, Colombia, from Dr. Juan de Dois Carrasquilla, on the use of anti-leprous serum prepared by him. The method of obtaining the serum and using it is described as follows:

The doctor first bleeds a leper, choosing an adult whose general condition is fairly good. The blood drawn varies in amount from a hundred to two hundred and fifty cubic centimetres. It is received into a sterilized vessel and carefully covered, kept away from the light, and, above all, kept perfectly quiet. In from twelve to twenty-four hours the superficial layer of serum, that only which is perfectly limpid, is

removed with a pipette if it has to be kept for some time before it is to be used, it is passed through a layer of powdered camphor contained between two layers of cotton, to preserve it, and it is kept away from the light and heat. Thus prepared, the serum is injected into an animal that is refractory to leprosy, preferably a healthy young horse in good condition. Roux's method of procedure is employed. The doctor thinks that forty-five cubic centimetres is the proper medium dose, given at intervals of ten days. The horse is bled in from five to ten days after the last injection, preferably from the jugular vein. The Nocard-Roux process is followed for obtaining aseptic horse serum, and it is treated in exactly the same way as the human serum.

The dose of the serum for use on the human subject is from one to five cubic centimetres, according to the strength of the serum, the constitution, age, and other circumstances of the patient, the period of the disease, etc., given subcutaneously. The locality to be preferred for the injection is that bounded by the iliac crest and a transverse line passing just beneath the trochanteric fossa, or, better still, just to the outer side of the trochanter major. Great care must be taken to make sure that the serum has not undergone any septic change. A full day should intervene between the injections. Febrile reaction follows in all cases, and the injection should not be repeated until this has subsided.

Further reports from Dr. Carrasquilla will be awaited with much interest.

Dr. Kitasato, the eminent physician of Japan, also claims to have discovered an effective remedy for leprosy, in the shape of an antitoxic serum procured from animals which have been made immune to the disease by injections of poison produced by the microbes.

Still another cure for leprosy is announced by Dr. Bouffé, a French physician.

Following the discovery, by Dr. Hansen, a Norwegian, of the microbe of leprosy, and the failure of experiments after the Pasteur method of vaccination, Dr. Bouffé came to the conclusion that leprosy, like psoriasis and eczema, which are minor diseases of the same type, only becomes developed in an organism as the result of the weakening of the nervous system, which has thus ceased to regulate the functions of nutrition, and that its evolution cannot be arrested until the nervous system is restored to its natural condition. He therefore began to treat leprosy with subcutaneous injections of orchitine, the famous liquid discoverd by the late Dr. Brown-Sequard. His method is thus practically a rehabilitation of that of Dr. BrownSequard. Its efficiency for the purpose indicated has not yet been demonstrated.

The Phonendoscope.-This instrument, invented by two Italians, Bazzi and Bianchi, and indorsed by high authorities in Germany, France, and Italy, bids fair to work a revolution in the fields of medicine and surgery to which the stethoscope has heretofore been the only instru-ment applicable. The latter is practically useful only in exploring by sound the regions of the heart and lungs: