tained equilibrium. In other words, the mech- | a steam-engine, or by the muscular power of a anism acts, practically, not in bringing the charcoal point back to its place when it gets out of it, but in preventing it from getting out of its place at all. The regulators actually employed are much more complicated than this, but this illustrates the general principle of their action, in the most simple form. The necessity for a constant regulation of the distance of the charcoal points arises from the fact that the action of the current causes a gradual consumption of the substance of the charcoal at the positive pole, occasioned partly by the combustion of it, and partly by the transmission of incandescent particles through the air to the negative pole. The engraving (p. 355) represents the appearance of the points after the process has been for some time continued. The luminous globules seen attached to the cones are the results of the fusion of earthy impurities contained in the charcoal. This gradual wasting of the points, especially of that connected with the positive pole, would gradually increase the distance between them, and so bring the process to an end, were it not for the action of the regulator. man; that is, by the consumption of the coal burned to drive the engine, or of the food digested in vital organs to supply the strength to the man. The light can be generated only by the expenditure of an equivalent force in some other form. The above cut represents one of the forms of the magneto-electric machine, as constructed by a French company called The Alliancea company established for the purpose of perfecting and manufacturing apparatus and machines of this character. It is only a general idea of its form, and of the principle on which it operates, that can be communicated by an engraving. The principle on which it is constructed is this, that when a bar of iron changes its magnetic state, a current of electricity is instituted, during the moment of the change, in a conducting wire passing across the bar at right angles. Thus if a short, round bar of iron is wound with an iron wire, the two ends of the wire being left free, and the coil or bobbin, as the French call it, thus made is brought suddenly up to any strong magnet, an electric current is for the instant induced in the wire, which may be made manifest through proper observations, by means of the two ends. If now the bobbin be contrary direction will be produced in the wire. To produce this light there must be a constant and powerful electric current, and to induce and sustain this requires the constant ex-as suddenly withdrawn, another current in a penditure of force in some other form. In the case of an ordinary galvanic battery, the force is supplied by the consumption of the zinc; but, by means of a magneto-electric arrangement-that is, an arrangement for the development of electricity by means of a rapid succession of magnetic changes produced through the revolution of a series of electro-magnets within a system of permanent magnets-the force is supplied by Of course the actual production of this effect does not depend upon the strength of the magnet, nor upon the suddenness of the approach and withdrawal of the bobbin. These circumstances only affect the result in respect to degree. The magnet must be powerful and the motions rapid to make the effect manifest. The machine, then, is simply a mechanical arrangement for causing a great number of such coils as are above described alternately to approach to and recede from the poles of powerful magnets, in very rapid succession. The electric force is so prompt in its action that no possible rapidity of motion that can be given to the bobbins will confuse it or interfere with its sending two distinct currents through the wire in contrary directions, as the bobbins advance or recede. This is wonderful, but it is in harmony with the other wonder somewhat analogous to it, that a telegraphic message may be sent along a wire through this same agency, by means of a series of separate signals following each other in very rapid succession, without confusion, and moving at the rate of many thousands of miles in a second. The machine illustrated in the engraving (p. 356) consists externally of eight ranges of powerful horseshoe magnets arranged around a hollow cylinder, with the poles turned toward the axis of the cylinder. There are seven of these magnets in each range, making fifty-six in all. This whole system is fixed to the frame of the engine so as to be immovable. THE ELECTRIO MIOROSCOPE. of the coils over the poles of the magnet would produce only a series of flashes, with perceptible intervals between them. It is found that by giving the cylinder a speed sufficient to produce about two hundred electric impulses in a second, the eye can no longer take cognizance of the interruptions, and the result is a uniform and continuous emission of a most intense and brilliant beam. In the centre is a revolving cylinder which nearly fills the opening left between the poles of the magnets, and upon this cylinder are fixed a set of double coils or bobbins, making one hundred and twelve in all. The ends of some of these bobbins are seen in the engraving. The precise arrangement of the mechanism con- Such a machine may be driven by means of nected with these coils can not be fully ex- any convenient mechanical power. In the enplained. All that it is necessary, however, for graving it is represented as impelled by a pulley the reader to understand is that they are so and band from a steam-engine in an adjoining placed that on causing the inner cylinder to re-apartment, as shown on the right. On the left volve, the ends of the bars which form the cores is the stand containing the charcoal points, of the bobbins are brought in rapid succession showing the light developed between them, into close proximity to the poles of the mag- and the apparatus for regulating the distance nets, alternately approaching to and receding which separates them below. from them with great rapidity. The consequence is that a series of electrical impulses is given in the wires coiled around the bars, each impulse being in the opposite direction from the one preceding it. These currents, almost instantaneous in respect to duration, succeed each other with inconceivable rapidity-the rapidity depending, of course, on the speed of the rotation of the cylinder bearing the bobbins. It is necessary that the speed should be great, for as the light, at the break between the charcoal points, only shines while the current is passing, and, moreover, as it changes its action somewhat according to the direction in which the current flows, it is plain that a slow motion One of the most curious and striking illustrations of the modern doctrine of the correlation of force is shown in this instrument by the fact that, although the central cylinder, bearing the bobbins, the turning of which seems to be all the work which is required to be done, is so nicely mounted, and on bearings so delicate as to call apparently for the exercise of only a very slight force to make it revolve, namely, that resulting from an almost inappreciable friction, it really requires a two-horse power to work the machine. The resistance comes from certain influences of the magnetic and electric agencies in their action upon each other, which influences have to be overcome by force, and this force is precisely that represented by the light developed at the break in the circuit. The machine is thus a contrivance for converting mechanical force into electricity, and then from electricity into light. The intense brilliancy of the electric light, and the extreme concentration of the radiant point, render it remarkably suitable for the microscope and the magic-lantern. The engraving (p. 357) represents the manner of employing it for the microscope. The electricity is produced in this case by a galvanic battery, as shown by the jars on the floor, instead of by a magnetoelectric machine-that is to say, the source of the power is the consumption of zinc, and not the consumption of coal. The first attempt to employ the electric light in the construction of public works was in the building of the bridge of Notre Dame, at Paris. The experiment was perfectly successful in enabling the workmen to continue their labors through the night, and in thus greatly diminishing the time required for the work. This trial was made, however, when the only mode of procuring the necessary electric power was by a battery, and the light was accordingly found to be quite expensive. Since then the much more economical mode of employing magneto-electric machines, to be worked by mechanical power, has been discovered, and the emergencies in which this light can be advantageously used are rapidly multiplying. It has been tried in mines, in caverns, on board ships, and in light-houses, and also in the construction of such works on land and in the open air as are of an urgent character requiring night labor. Although the electric light rivals in brilliancy that of the sun, the appearance is very different when employed for purposes of general illumination, on account of the extreme concentration of the radiant point, which makes the contrast of light and shade so sharp and decisive as to produce a very peculiar effect. The light of the sun, besides radiating in the first instance from a comparatively wide surface, is greatly diffused in passing, for so great a distance, through the earth's atmosphere. Every minute globule of water which floats in the air, every mote, every particle of dust, every microscopic insect and seed and spore, intercepts a portion of his beams, and becomes a new centre of radiation. The result is a general illumination of the whole sky, and a diffusion of the light before it reaches the abode of man, which adapts it far more perfectly to his various wants. The electric light has already begun to be practically employed, not only for the purposes above referred to, but also for light-houses and signal lights on board ship, for both of which it is admirably adapted on account of its great penetrating power in misty and foggy states of the atmosphere. It is also found to be well fitted for the production of stage effects in operas and theatres. It is used for this purpose in Paris, and to some extent in this country. It has also been employed as a signal light from the mast-head of a ship, in one of the steamers of the French line, and has thus been displayed in New York Harbor, attracting great attention from all who beheld it. The probability is that the employment of it for these and other uses will greatly increase; and it is by no means certain that it may not in the end be found to be the most effective and economical mode of illuminating large public halls. remarkable low so low, HE Asiatic squadron of our navy has within places in the world; extending from Singapore on the south to Siberia on the north, it has the extremes of climates, and almost the extremes of peoples; for Singapore is English, and Siberia is almost savage. Our government had sent out three gunboats to aid in the suppression of piracy in the China seas, and to one of these it was my fortune to be attached. Our station comprised the southern waters of China, and a stay of ten months in "Hong-Kong and the adjacent waters" found us quite ready for a change. We preferred to go to Japan and spend our summer there; but our wishes were as nothing, and we were sent to Siam as the bearers of a present of arms and ammunition to the Prime Minister from our Navy Department, with a letter from the Secretary of State and the other necessary accompanying documents. a distance of forty miles from the sea, is very As we crossed the bar and entered the river, just before sunset, a most beautiful sight met our gaze-an island covered with a temple of unique architecture, glowing like burnished marble, and looking more like a creation of fairy-land than I supposed any thing of mortal building could look. So tortuous was the channel that we passed by three sides of this thing of beauty. I can not attempt to describe it; nothing but an engraving could do that. It seemed impossible that any Eastern people of to-day could erect such a structure; but we learned afterward that it was of brick, whitewashed. This detracted from the idea of difficulty, but it could not diminish its beauty. The banks of the river were very low; and some of the officers going to the mast-head, reported that nothing could be seen save a vast expanse of green, as far as the eye could reach. As we passed up the stream we saw oranges and bananas in profusion, with here and there a temple with its attendant out-buildings raised on piles, The coast of Siam, about the mouth of the to be clear of any unusual rise of the river. river Menam, on which Bangkok is situated, at | We heard the chattering of monkeys, but could Our passage of ten days had nothing of unusual interest in it; it was simply steaming slowly (for we could do no more) against the southwest monsoon, under a cloudless sky and a burning sun. us. see none, though the pilot pointed them out to We passed numerous boats, some ships, a few houses, and the openings of very many canals, which led to various places in the surrounding country, and which were the only lines of communication. It was dark for an hour before we reached the anchorage; and it was rather unpleasant to be going along with a strong flood-tide among fishing-boats, and possible floating houses; but our pilot knew the way; and keeping in mind the Mississippi expedient of sounding the whistle before rounding a curve, we reached the city in safety, and let go our anchor just in time to avoid swinging into a huge Chinese junk. In the morning the junk moved away from our neighborhood, evidently disliking our company. The first thing to be done was to advise the Consul of our arrival, and request him to communicate with the Prime Minister the mission upon which we had come. Pending the Consul's appearance, a messenger from the Minister appeared in the person of his nephew, as bright and intelligent looking a young man as one would wish to see. He was neatly dressed in trowsers, jacket, and waist-scarf, but wore neither hat nor shoes. His hair was cut in the Siamese fashion-short, except for a prominence not unlike a shoe-brush, and about as long, extending from the front to the crown of the head. He inquired the reason of our coming, and was told that the Consul would communicate officially with the Prime Minister, or "Kalahome," as he is called in Siam. Whereupon he disclaimed any desire to go beyond the bounds of "red tape," and said that he had been sent merely to welcome us to the capital. The Consul (a missionary) came on board, and soon dispatched his letter, requesting an audience as early as possible. In the afternoon an answer came, appointing the next day at ten o'clock for the reception of the presents. During the day we had something of an opportunity to look about us; we found that we were anchored some two miles from the King's palace, and about half a mile below the foreign residences. The city extends along the bank of the river, here very narrow, for several milesten, I should think-and by no means appears to be as populous as it really is. The river forms the principal highway, and its surface is covered thickly with boats from morning till night. Here may be seen all descriptions of water craft; from the tiny canoe, propelled by one paddle, to the royal barge with one hundred and fifty rowers; from the native sail-boat to the full-rigged foreign ship or the smoky steamer. A canal extends entirely around the city, with numerous cross canals, so that access by water to all portions is very easy. There are but few horses, and these only about the grounds of the King and nobles, and a few at the hotels; there is a road, about a mile or more in length, which the late King constructed for the benefit of the foreign residents. There are but few streets, and these very narrow; but the various palaces |