light; but the importance of the question, relative to the general administration of lighthouses, is much less than was at first supposed. In 1863, in a notice of the applications of the electric light, the author suggested the lighting of vessels by it. The maritime exhibition at Havre shows that the suggestion has been considered, at least in principle. In the point of view of lighting the course of a ship, no one will deny that the oil lantern is insufficient to prevent collisions at night; while the electric lantern would illumine the air all around, and the rocking of the vessel would cause such changes of light as would attract the notice of the men on other vessels. When the whole cost of a ship is considered, that of electric engines is insignificant; two or three horse-power will work a magneto-electric machine. And the electric light will serve other purposes on board a ship. Recent experiments have shown that it would be possible to assist a ship in her course by dazzling the steersman by a jet of light, when an oil lantern would not be seen by him. It can also be used to light under water; an application that concerns the repairs of the sheathing and hulls of vessels, the finding of lost articles, and the catching of fish. The fish are confused by the light, and then easily caught. Mons. Dubosc has constructed a lantern well fitted to enclose an electric lamp. The conducting wires are connected so that there is no chance for water to leak into the lantern. This apparatus can, without fear of too high pressure, be lowered to great depth in the sea.-(Translated for Van Nostrand's Engineering Mag.)

The London Chemical News states that the electric light at Dungeness can now be worked by either of the two engines, so that no disturbance occurs when one requires repairs. The services of the high-class engineers and firemen have been dispensed with, and the Elder Brethren have their own ordinary keepers trained to drive the engines as well as to attend to the lamps, a steady, old, experienced keeper being placed at the head of the establishment. Since the alterations made at Dungeness, the light there has worked with great regularity and efficiency, and the Elder Brethren have proposed to place similar lights at the South Foreland, Lowestoft, and Souter Point. The English Board of Trade approve the extension of this mode of illumination to the South Foreland and Lowestoft, but suspend their decision respecting Souter Point. The committee of Elder Brethren who attended the Paris Exhibition say, that so far as the eye is a test, the power of the English fixed light was considerably in excess of the French, and when both machines were in use, and there was a good current, the fixed beam of the English light did not contrast unfavorably with the revolving one of the French, the flash of which is of great power. The contrast of the electric fixed light with the French firstorder oil dioptric revolving light was very

marked; indeed, the one may be said to put the other out. But the most beautiful feature of the electric was the extraordinary beam it gave. It shone night after night, large, steady, and lustrous as a planet, and you could see in the darkness a beam passing as far as the eye could see. From the tower, with the light at the back, it was very marked, and quite lit the hills round Paris. The whole horizon in the plane of the light showed the white beam, and at the distance of four miles it shone upon the windows of some houses, making them appear to be lit up. By extinguishing and relighting quickly several times this was very plain. Altogether the light was very remarkable, and the committee were glad to be able to report such an advance as the powers of the light show over that at Dungeness; indeed, the latter gives to the observer no conception of what the present one is; and it is satisfactory to know that the result of five years' work and observation, with imperfect and ill-arranged apparatus, has now borne such good fruit; and that as England was the first to test and adopt this adjunct to the sources of light-house illumination, so she still retains her superiority. It is due, however, to Mr. Holmes to say that great as are the improvements already effected, he states that he is confident he can yet greatly increase the illuminating power before the present apparatus is reerected at a permanent station.

Satisfactory experiments have been made with the electric light on board the French iron-clad ship Heroine and the yacht Prince Jerome, to ascertain the value of the light for signalling purposes. The machine was furnished by the Alliance Company, producing a light equal to two hundred Carcel burners, or sixteen hundred candles. An ordinary newspaper could be read in the direct line of the light at the distance of 1,531 yards. Signalling was most easily done by short and long flashes, and was found to be practicable. The Government commissioners reported, after an investigation, that the apparatus showed a very powerful focus of light, perfectly suited to night signalling, or for throwing a light over a coast or a ship; and that it would be most useful on board the flag-ship of a commander-in-chief. By the aid of this light, the Prince Jerome was enabled to steam by night through the intricate navigation of the Bosphorus, when the yacht belonging to the Viceroy of Egypt was obliged to wait until daylight. On some steamers of the French commercial marine the same light produced by the magneto-electric engine has been introduced, and is regarded as a practical success.

Experiments in Electrolysis.-M. Bourgoin has published a memoir on the electrolysis of organic acids and their salts. He has found by experiment that the action of the electric fluid is in reality only a fundamental action on all acids and salts, whether mineral or organic. It separates the basic element which goes to the

negative pole, while the elements of anhydrous acid and oxygen, which answer to basic hydrogen or to metal, fly to the positive pole. Such, he claims, is the fundamental action of the electric current. M. Bourgoin has specially studied the action of the current on neutral tartrate, on a mixture of tartrate and alkali, and on free tartaric acid. To examine the action on tartaric acid, a concentrated solution of the neutral tartrate of potash is conveniently operated upon. As soon as the current passes, the solution becomes alkaline at the negative pole; only a moderate disengagement of gas is produced at the two poles. The principal result is the formation of a white precip itate, which is slowly but continuously deposited from the positive electrode. Analysis shows this substance to be wholly cream of tartar. The solution at the positive pole remains neutral during the experiment. The gas evolved at the positive pole was composed of carbonic acid, oxygen, carbonic oxide, and nitrogen. Nearly the whole of the loss takes place at the positive pole.

The tartaric acid thus regenerated at the positive pole forms, with the neutral tartrate, cream of tartar; there is, however, some tartaric acid destroyed by oxidation. The action of the current on a mixture of neutral tartrate and alkali produces quite different results to those obtained with neutral tartrate only, notwithstanding that the fundamental action is the same. At the positive pole a mixture of carbonic acid, carbonic oxide, oxygen and hydride of ethylen is evolved. M. Berthelot discovered acetylen also in the sample of the gas sent him by M. Bourgoin. The decomposition of free tartaric acid yielded the same products as the neutral tartrate, though in different proportions. The carbonic acid is the dominant product from the first; the carbonic oxide diminishes as the experiment proceeds; the same is the case with the oxygen and nitrogen, though to a less extent. Acetic acid is formed at the positive pole. After the fifth day the experiment had been in progress, the solution in the neighborhood of the positive pole contained a large quantity of acetic acid, which was isolated as acetate of baryta.

New Batteries.-M. Cauderay has devised a battery, composed of four elements, of which the electro-motors consist of perfectly new carbon plates, the one being what is termed agglomerated carbon, the other gas carbon. These plates never having been previously used, were, consequently, free from acids and salts. The battery was connected up in the ordinary manner, the carbon of one cell being connected to the gas carbon of the other, and 80 on. Immediately on being placed in action the battery gave a current of 45° on a galvanometer, and rang a bell perfectly for a space of about ten minutes. The intensity diminished rapidly after that time; but after a rest of about one hour the battery had almost recovered its previous force. Each time that the

battery was tried a rest was always sufficient to restore its action; but after each trial the force became less, until, after trying it for thirty-five days, it became so weak as to give only 3° on the galvanometer, and at that period a remarkable change took place. The sign of the current altered: the current, which hitherto had been passing from the agglomerated to the gas carbon, was now proceeding in the opposite direction. M. Cauderay states that, on the second day after the fixing of the battery, he thought he remarked a strong smell of gas-tar. He perceived that this smell was accumulated around the last gas carbon forming the positive pole of the battery. It seemed to him then extremely probable that the gases which diffused those smells had been withdrawn from the interior of the carbons by the current, to be accumulated and disengaged at the positive pole, for previous to their being immersed the carbon had no smell whatever. The agglomerated carbon placed in the same cell was covered by bands of very brilliant colors, among which were Prussian blue, violet, green, etc., arising, he supposes, from the decomposition of salts, or, perhaps, from a small quantity of tar contained in the gas carbon. A peculiar fact in connection with these bands is, that they were precisely similar in order to those of the solar spectrum-the red at top and the violet below, with all the intermediate colors of the spectrum.

In form

M. G. Plante has invented a new "secondary battery," as he calls it. It consists of a novel and peculiar arrangement for multiplying the power obtained from a weak source. it is not unlike an ordinary condenser. There is a rectangular gutta-percha vessel provided with lateral grooves, and containing a series of lead plates immersed in dilute sulphuric acid. As in a large condenser, the odd plates are joined in one series and the even plates in another series; to either end is attached one of the poles of a weak source. Such a battery, with six plates only, and a source of two small nitric couples, was strong enough to create temporary incandescence in a platinum wire one millimetre thick and eight centimetres long. By increasing the size and number of the plates, more powerful calorific effects, such as incandescence of iron and steel rods, may be obtained by charging the battery with two or three Bunsen's elements. An arrangement, termed by the same inventor his "secondary tension battery," produces still more remarkable results. The apparatus consists of forty secondary couples, each couple of lead plates being in a narrow gutta-percha vessel, immersed in dilute sulphuric acid, the pole of each vessel being connected to a peculiar commutator, so that the plates could be joined as an arrangement of tension or as one of surface. This battery was charged with three couples of Bunsen's medium-sized battery. On applying the current from the secondary circuit, a platinum wire, two metres long and one-quar

ter of a millimetre thick, was rendered incandescent for a few moments, and the voltaic arc was also obtained. M. Plante remarks upon this that it is not, as in the case of induction, the direct production of one physical effect by another physical action; but the final result is none the less an accumulation or a modification of electrical force, which can be utilized under certain circumstances.-(Mechanics' Magazine.) An Electric Piano.-M. Spies, of Paris, has invented an electric piano, which has been exhibited at a meeting of the "Société d'Encouragement," and elicited great surprise and admiration. The electrical arrangement consists, in the interior of the piano, of a series of electro-magnets, which act upon the hammers that strike the wires. These hammers communicate in the ordinary way with the keyboard, but on their opposite side they have small wooden rods, terminating with armatures, which are attracted to the electro-magnets whenever they become active. The "directing organ," as it is called, is constructed as follows: First, there are two wooden rollers, with an intermediate roller of metal. The paper, specially prepared with a series of holes, placed in positions representing the several notes of music, is rolled around one of the wooden rollers; passing over the metal roller, it is drawn off and wound around the second wooden roller. This unwinding keeps it always at a uniform tension. Second, a clockwork movement gives motion to the rollers. Third, a small keyboard, with movable copper hammers, is placed above the intermediate roller, so that the heads of the hammers rest upon the paper band (prepared as described) which represents the musical notes. The battery is a series of thirtysix Daniell's cells. One pole of the battery connects with the small keyboard; the other, through the various electro-magnets of the piano, with the metallic roller. The rollers being set in motion by the clockwork, cause the prepared band to be unrolled and pass on the metallic roller. Whenever a hole in the paper comes under the keyboard, the lightlyresting hammer at once makes contact, a current passes through to the electro-magnet, which attracts the hammer, and the required note is struck; and so, from a series of these prepared holes a number of successive electric contacts are made, acting upon the several electro-magnets, causing the various hammers to strike the required notes. The principle of the piano is really that of automatic telegraphy, except that, in transmitting messages automatically by the ingenious apparatus devised for that purpose, the result is a permanent and visible record; whereas, in the case of the electric piano, the result is simply one of sound. The electric current being uniform throughout, produces a uniform blow with all the hammers; but, by the application of pedal and sourdines, M. Speiss causes any music to be played with the required expression.

Magnetic Alphabetical Telegraph.-Rev. H. B. Wilde, of Reading, England, has invented a new magnetic alphabetical telegraph. The sender has a dial plate, inscribed with the letters of the alphabet and other signs. This has a jointed handle, which may be quickly moved round the dial, and may be checked at any point, by a ratchet. The instrument upon which the messages are received has a smaller dial, traversed by a delicate indicator hand. The movements of the handle by the sender of a message are accurately reproduced on the index plate at the other end of the line, and may be easily read. A series of permanent horseshoe magnets furnishes the power. These are united to form a compound magnet, to the north and south poles of which are fixed, vertically, independent electro-magnets, their upper ends being inserted through holes in a brass plate, and planed off so that the iron and brass present one smooth, flat, surface. The handle employed in sending messages gives motion to a thick, circular piece of soft iron, which is supported above the compound magnet by a suitable socket-piece. The edge of this plate is divided into twenty-eight equal spaces, which are alternately notched out right and left, so that there are fourteen projections or teeth and the same number of corresponding spaces. The iron plate in its rotary movement lightly rubs the brass plate through which the ends of the electro-magnets are inserted, and as the projections and spaces at the edge of the plate alternately pass over these ends, positive and negative currents are excited in the insulating wire surrounding the electro-magnet. The currents being conveyed to the receiving instrument induce rapid changes in the polarity of an ordinary electro-magnet, between the poles of which a small permanent magnet vibrates; each vibration liberating the teeth of an escape-wheel propelled by a very light train of clockwork wheels and mainspring. The axis of the escape-wheel carries the hand or index of the dial. Thus, as the sender moves the handle over the letters on the dial, positive and negative currents are alternately induced in the conducting wires, which currents cause the hand of the receiving instrument to pass over the same letters.

Electric Apparatus for Blasting Purposes.— A new dynamo-electric apparatus, especially adapted for blasting operations, the invention of Mr. C. W. Siemens, is described by the Mechanics' Magazine. It is an adaptation of the larger machine contrived by him for the conversion of great mechanical force into dynamic electricity (see ANNUAL CYCLOPÆDIA for 1867). The essential difference between the Siemens apparatus and that of Wilde is the absence, in the former case, of the magnetoelectric machine as the exciting agent. An electro-magnetic machine is alone employed, having as its exciting agent its residuary magnetism only. The electro-magnet is provided with a magnet-cylinder, within which revolves

a small Siemens armature. The coils of this electro-magnet are traversed by the current produced by the rotating armature, after being, by means of a commutator, made to flow in one direction only. At the commencement of rotation, the armature is acted upon merely by the weak residuary magnetism of the electromagnet, and consequently only weak currents are produced in its surrounding coil. These weak currents, passing through the coils of the electro-magnet in the same direction, instantly increase the residuary magnetism, thereby again producing increased induction currents in the armature, and so on until the iron of the electro-magnet has taken up the highest amount of magnetism which it is capable of holding. In this arrangement the coils are short-circuited, and so kept during the revolutions of the handle when current and magnetism are developed to their utmost extent. By now suddenly opening this short circuit a very powerful current of short duration (expressly adapted to blasting purposes) will pass through a lime connected to the terminals. The instrument is claimed to be handy, portable, and useful in all weathers, having a superiority over galvanic batteries and also over staticelectric machines, which only act in fine weather. The instrument may be actuated either by magnetism or by a current from a single cell. After that there is always sufficient residuary magnetism to induce a weak current in the armature; and thus a never-failing supply of electricity is at command for the object required. In blasting operations it is said to work with great success. It is also adapted for the release of clockwork or signal bells for railways, and for the sending of currents in rapid succession into a line of telegraph.

Electro-capillary Paper.-M. Becquerel has investigated certain electro-capillary phenomena, and describes the process and results as follows: He prepared parchment-paper with ordinary filter-paper by immersing in sulphuric acid, containing fifteen per cent. of water, withdrawing immediately and washing with a large quantity of water. A tube closed by a diaphragm of this material, and filled with a saturated solution of nitrate of lime, was plunged into a solution equally saturated with sulphate of soda. Stalactites formed on the under surface of the paper, composed of crystallized double sulphate of soda and lime. These stalactites are of variable diameter, varying according to the size of the pores which allow the passage of the nitrate of lime. By diminishing the size of the capillary tubes, the passage of the liquid is indefinitely retarded, until it at length becomes inappreciable. There is a point, in regard to the diameter of these capillary tubes, where the electro-capillary force ceases to act, and where complete filtration ensues; a single pore is sufficient to produce this effect. For this reason it is necessary that the parchment

paper be uniform. Some experiments were made with siliceous diaphragms. Columns of sand, varying from five millimetres to five centimetres in height, kept in position in each case by a tuft of asbestos, were substituted in a former apparatus. In operating in Dutrochet's way, with solution of sugar, solution of salt, and distilled water, simple filtration took place, instead of a strong endosmose with the organic membrane; but this was not the case when a saturated solution of sulphate of soda was placed in the tube, and in the outer vessel another of chloride of barium, an endosmose of two centimetres resulting in two days. No precipitate is seen in the outer vessel, so that there is only a displacement of the solution. In placing in a tube closed with a diaphragm of parchment-paper a solution of sugar or of salt, colored with litmus or other coloring matter, and water in the outer vessel, a strong endosmose is produced in the tube, and at the end of a few days traces of color in the water are only seen with difficulty; the color is completely arrested by the membrane.

An Improved Voltastat.-Professor Guthrie has exhibited to the British Chemical Society an improved Voltastat by which the current of a galvanic battery may be maintained perfectly constant and regular by a self-acting arrangement, which is thus described: A vertical glass cylinder of about the size of a test tube is charged with dilute sulphuric acid, with a layer of mercury below occupying about one-third of its total contents. Partly immersed in the acid liquid is a pair of platinum electrodes insulated by glass fused upon the wires at that portion which passes through the cork stopper of the jar, and a comparatively wide glass tube open at both ends is fixed in the same cork, with its lower extremity dipping below the level of the mercury, while another delivery tube with bulb and capillary orifice provides for the slow escape of the mixed gases resulting from the electro-decomposition of the water. This apparatus having been placed in the battery circuit, say of three Bunsen cells, evolves the oxyhydrogen gas with a rapidity which may be easily regulated by the size of the aperture; if, then, the activity of the battery is increased, the larger volume of gas, unable to escape, exerts a greater degree of pressure upon the liquid contents of the cylinder, and the mercury is forced up the open tube, whereby the column of liquid descends and smaller surfaces of the platinum plates are left immersed, and the power of conduction is to a corresponding extent lessened. In this manner the author states that he found no difficulty in maintaining a perfectly uniform current for a period of six or seven hours, and any required adjustment could be made by altering the size either' of the apparatus or of its component parts. By collecting the gases evolved, this little arrangement could also be made to serve as a voltameter. The president of the society, Mr.

Warren De la Rue, in remarking upon the ingenuity displayed in the construction of the apparatus, suggested that, while it would be found serviceable in electro-plating and other applications where a somewhat intense current was employed, he doubted its use in the ordinary electrotype process for the deposition of copper, where weak currents only were required.

A New Exciting Liquid.-In a note to the French Academy of Science, M. Delaurier mentions a new exciting liquid for galvanic batteries. He says that, in order to obtain very powerful batteries disengaging no deleterious gas, and of very cheap maintenance, he has solved the problem of transforming azotic acid into sulphate of ammonia, under the influence of sulphuric acid and hydrogen. This he does by the agency of protosulphate of iron; the proportions are twenty parts of the protosulphate dissolved in thirty-six parts of water (the operation being sheltered from contact with the air), to which are added, with stirring, seven parts of diluted (equal parts) sulphuric acid, and then in the same manner one part of diluted (equal parts) azotic acid. He says that the resulting liquid is the most energetic and most economical that he knows for an exciting liquid for iron, zinc, and other metals without any disengagement of hydrogen or binoxide of azote. In the use of this liquid with nitric acid in Bunsen's pile, the action goes on without any exterior emanation of nitrous gas, and without the emission of hydrogen in the interior, and consequently the platinum does not polarize.

Decomposing Action of the Voltaic Arc on Certain Substances.-Mr. F. P. Le Roux, in a paper in the London Chemical News, offers evidence to show that the earthy and alkalineearthy oxides undergo a real decomposition in the voltaic arc. If a cylinder of magnesia, or lime, or strontia, be fixed in the voltaic arc, a slight cavity instantly forms at the base, and the conditions remain the same for an indefinite time; the arc continuing to play upon the body without inducing any change but the vitrification caused by the siliceous vapors emitted by the impure charcoal. If, however, the cylinder of earthy matter be brought into actual contact with the charcoal points and the pressure maintained with a slight spring, different results follow. If a pencil of lime, or even plain chalk, be used, the carbons will hollow out in it a sort of trench in which the heat is condensed as in a sort of reverberatory furnace, and the amount of light emitted is proportionally augmented. On examining the light with a piece of black glass it presents the appearance of an opaque luminous cloud in which the extreme ends of the charcoal are undistinguishable, their usually well-marked brilliancy being lost in the mass of light, and there is a sensible evolution of whitish fumes. The spectroscope displays an intermittent spectrum filled with large and brilliant rays, which are recog

nizable as those described by different authors as characteristic of calcium, but their number and intensity is greater and they are better defined. This is not surprising if the difference between the luminous intensity attainable by this process and by those hitherto employed be considered. It would be doubtless possible by this method to obtain much new information respecting the spectra of metals, provided only pure products were employed.

The employment of strontia gives analogous effects under the same conditions, the light assumes a characteristic red tinge, and the spectroscope displays the rays characteristic of strontium, thus presenting a simple means of enriching the electric light with red rays. It may be here remarked that the flame always contains a large proportion of white light, for if the metal be set free in some parts of the flame, in others it returns to the state of oxide, the incandescence of which always yields a white light.

- The

Color-effects of Electric Discharges. American Journal of Science for May, 1868, contains the substance of a paper, read by M. Becquerel before the French Academy, on the effect of coloration presented by discharges from an inductorium taking place between the platinum wire and the surface of a liquid. The apparatus employed by the author was very simple, consisting merely of a glass tube, partly filled with a saline solution in contact with a platinum wire forming one pole of an inductorium. The other pole was formed by a platinum wire, the extremity of which was placed a few millimetres above the surface of the liquid, the discharge taking place between the liquid and the wire. In case the inductorium is of low power, coloration is not observed when the liquid is positive and the wire negative, but only when the wire is positive. But when the coil is powerful, and the salt dissolved easily vaporized, coloration is observed in either case, though the maximum is given when the wire is positive. With a sufficiently powerful coil, the luminous effects of the discharge are very brilliant. The spectrum of the light produced in this manner is more complex than that resulting from the introduction of small quantities of saline matter into a non-luminous flame. The water is vaporized and we have lines due to oxygen and hydrogen; the temperature is also higher than that of the flame of a Bunsen's burner. With very pure water the intensity of the discharge is feeble and the spectrum contains the red and blue hydrogen line corresponding to the dark rays C and F of the solar spectrum. With a strong solution of chlorohydric acid in water the tint of the discharge is slightly violet and the two red and blue rays are more distinct than with water. There are also an orange band and a few fainter rays throughout the extent of the spectrum. Avery small quantity of saline substance in water is sufficient to communicate to the light of the discharge the color due to the elements of the