Voltigeur

“ The actual bocca of the volcanic vent whence the steam roars off constitute the cone a veritable hydro-electric machine. Mechanical energy in various forms is transformed into electric energy. Chemical action is going on both in the solid and in the vapourous and gaseous emanations as they rush into and remain in the air or descend from it, and chemical action is transformed in part into electric energy. ”

“ A B C is the electrified cloud, the two ends of which come near the earth. The lightning discharge occurs at C. A man at F is killed by the return stroke, while those at D, nearer to the place of discharge, but further from the cloud, receive no injury. It may be mentioned that it was the action of the return shock upon the limbs of a dead frog in Galvani’s laboratory that led to the Professor’s experiments on animal electricity, and further to the discovery by Volta of that form of electrical action which bears his name. ”

“ A wet Sponge then, squeez'd hard and fill'd with this cold Mucilage, was held in the Hand of an electrified Man, when the Drops forced out by the Electricity, assisted by the Tenacity of the Liquor, hung some Inches from the Sponge, and by a Drop of this I fir'd not only the Spirit of Wine, but likewise the inflammable 37 Air before mentioned, both with and without the Explosion. What an extraordinary Effect is this! That a Drop of cold Water (for the Seeds contribute nothing but add Consistence to the Water) should be the Medium of Fire and Flame. ”

“ Volta, whom the international congress of electricity so deservedly honored by giving his name to one of the units of electricity, is the genius who first constructed an instrument which would give a continuous flow of electricity. The Voltaic pile is a very great invention. Volta was much more, however, than merely an ingenious inventor. He was a great scientist who made discoveries not only in electricity but in various other branches of physical science. ”

“ Before that electricity was known only by the instantaneous discharge or spark. From the name of Volta is derived the word volt, which designates the unit of electro-motive force. The adjective voltaic is synonymous with galvanic, as voltaic or galvanic cell, voltaic or galvanic current. For a long time it was thought that such an adjective was needed to designate electric currents generated by chemical action as a peculiar kind of electricity. We no longer think of electricity which is generated by chemical action as different from that generated by a dynamo or from any other source. ”

“ We have decomposed the thunderbolt, as Newton disentangled light. We have perceived that these thunderbolts, formerly borne by the eagle of Jupiter, are really only electric fire; that in short we can draw down thunder, conduct it, divide it, and render ourselves masters of it, as we make the rays of light pass through a prism, as we give course to the waters which fall from heaven, that is to say, from the height of half a league from our atmosphere. We plant a high fir with the branches lopped off, the top of which is covered with a cone of iron. The clouds which form thunder are electrical ”

“ The sage Mambres, having said everything he could to comfort the princess, but without succeeding in so doing, ran to the old woman.
"My companion," said he to her, "ours is a charming profession, but a very dangerous one. You run the risk of being hanged, and your ox of being burned, drowned or devoured. I don't know what they will do with your other animals, for, prophet as I am, I know very little; but do you carefully conceal the serpent and the fish. Let not the one show his head above water, nor the other venture out of his hole. I will place the ox in one of my stables in the country. ”

“ It trailed over the soil, here lifting a ragged flock or tag of fog a few feet above the earth, there dropping it again and smearing water over all it touched. Vapor condensed on every twig and leaf, but only leisurely, and slowly dripped from the ends of thorns and leaves; but the weight of the water on some of the frosted and sickly foliage brought the leaves down with it. Every stone in every wall was lined with trickles of water like snail crawls. The vapor penetrated within doors, and made all articles damp, of whatever sort they were. ”

“ We have means of searching into the constitution of water beyond any that are afforded us by the action of heat, and among these one of the most important is that force which we call voltaic electricity, which we used at our last meeting for the purpose of obtaining light, and which we carried about the room by means of these wires. ”

“ The novelty which distinguishes the generator from all others, consists in the manner of conveying the heat from the fire to the water, without exposing the generator to the action of the fire. This is accomplished by means of the circulation, in iron tubes, of a current of hot water, which is entirely separate from, and independent of, that to be evaporated in the generator. ”

“ But although the drop has fallen from a greater height than in the previous splash, the energy of the impact, instead of being expended in raising the same amount of liquid to a greater height, is now spent in lifting a much thicker adherent column to about the same height as in the last splash. There was sometimes noticed, as seen in Fig. 9, a tendency in the water to flow up past the milk, which, still comparatively unmixed with water, rides triumphant on the top of the emergent column. ”

“ When the vapours reach in the pipe from the clouds near to the earth, it is no wonder now to those who understand electricity, that flashes of lightning should descend by the spout, as in that of Rome. ”

“ VOLTA, ALESSANDRO (1745-1827) , Italian physicist, was born at Como on the 18th of February 1745. He is celebrated as a pioneer of electrical science, after whom the "volt" is named. In 1774 he was appointed professor of physics in the gymnasium of Como, and in 1777 he travelled through Switzerland, where he formed an intimate friendship with H. B. de Saussure. In 1779 a chair of physics was founded in Pavia, and Volta was chosen to occupy it. In 1782 he journeyed through France, Germany, Holland and England, and became acquainted with many scientific celebrities. ”

“ Whether subterranean electric currents if once excited might sometimes possess the decomposing power of the voltaic pile, is a question not perhaps easily answered in the present state of science; but such a power, if developed, would at once supply us with a never-failing source of chemical action from which volcanic heat might be derived. ”

“ When man shall attain the perfect vacuum, then the rude ether blush of the electric-light bulb will give forth many times more light, purified and heatless, soft and healing as the light of the stars, penetrating as the sun. An examination of the firefly, when emitting flames or light, shows bodily movements that cannot be understood to mean anything else than vacuum producing. ”

“ When the wind comes on your side it finds the obstacle presented by the loftier building, and rebounds: an eddy is formed, and whirling about on itself it becomes engulfed in your chimney-flue, or at least obstructs for a time the passage of the smoke. In such a case the flues should bifurcate; as the pressure of the wind is never exerted equally in both orifices, the air rushing into one makes the smoke issue violently through the other. ”

“ The splash is insignificantly small and of very short duration. [3] If the drying and polishing be not so perfect, the configurations of Series VII. are produced; while if the sphere be roughened with sandpaper, or left wet, Series VIII. is obtained, in which it will be perceived that, as was the case with the liquid drop, the water is driven away laterally, forming the ribbed basket-shaped hollow, which, however, is now prolonged to a great depth, the drop being followed by a cone of air, while the water seems to find great difficulty in wetting the surface completely. ”

“ The accompanying illustration (fig. 22) is an example to the point. It represents a barn furnished with a lightning conductor and filled with new-made hay, which is a better conductor of electricity than the material of which the barn is constructed. This hay is giving off the stream of warm vapour which is pouring out of the opening at the end, and forms an invisible band of conducting matter between the thunder-cloud and the barn, as marked out in the engraving by the dotted lines, the direction of the wind being shown by the arrow and the trees. ”

“ But the electro-motive force ascribed by Volta to the metals when in contact is a force which, as long as a free course is allowed to the electricity it sets in motion, is never expended, and continues to be exerted with undiminished power, in the production of a never-ceasing effect. ”

“ Again, in selecting a place for bivouac, we must bear in mind that a gale never blows in level currents, but in all kinds of curls and eddies, as the driving of a dust-storm, or the vagaries of bits of straw caught up by the wind, unmistakably show us. Little hillocks or undulations, combined with the general lay of the ground, are a chief cause of these eddies; they entirely divert the current of the wind from particular spots. Such spots should be looked for; they are discovered by watching the grass or the sand that lies on the ground. ”

“ The mass of water-vapor which forms the clouds becomes electrically charged just as a rubber comb does when rubbed on the hair on a dry day, or as an ebonite ruler does when rubbed on a cat-skin. Perhaps by contact with the air, which is in motion, the particles of water become charged, and by the union of multitudes of these the clouds are charged to a tremendous pressure. ”

“ From that fervid earth, warmed from within by volcanic heat, and basking ever beneath the equatorial sun, arose vapours as deadly to human life as the fruits were exciting and delicious to human senses. ”

“ One person only (Lagrange) was between us. He stayed about an hour—till the meeting was over. Volta read a memoir on Galvanism and explained his theory of the action of the voltaic pile or battery. His opinion is that all the appearances that are called galvanic [Pg 74] are owing to the action of an electric fluid, and he says that the simple tact of two metals—silver and zinc, for instance—is sufficient to set the electric fluid in motion; and if the metals are insulated, one of them will become electrified positively and the other negatively. ”

“ If the particles of water bring electrical fire when they attach themselves to air, the repulsion between the particles of water electrified, joins with the natural repulsion of the air, to force its particles to a greater distance, whereby the triangles are dilated, and the air rises, carrying up with it the water. ”

“ Volta thought that the electricity was not in the dead frog but in the iron and copper. He experimented and found it to be so: whenever he brought together the iron and the copper, there was electricity; and this electricity [Pg 154] made the dead frogs jerk their legs. Volta tried to produce electricity differently from what it had been produced before. Before that they used to get electricity by rubbing glass or sealing-wax. But Volta got electricity by uniting iron and copper. ”

“ As the drop descends the hollow becomes wider and deeper, and finally closes over the drop (Fig. 3) , which, however, soon again emerges as the hollow flattens out, appearing first near, but still below the surface (Fig. 4) , in a flattened, lobed form, afterwards rising as a column somewhat mixed with adherent water, in which traces of the lobes are at first very visible.
The rising column, which is nearly cylindrical, breaks up into drops before or during its subsequent descent into the liquid. ”

“ Volta is, therefore, above all others, the one who broke ground not only for an immense amount of new knowledge in physics, chemistry and physiology, but who also made possible rapid progress in practical electricity, in telegraphy, in electric motors and power machines, in electroplating and the marvelous results in electro-galvanism which constitute our most wonderful mechanical effects at the present time. ”

“ It is on this transference of electricity from one surface to another, by simple contact, that Volta explains the action of the pile invented by himself, as well as that of all similar arrangements. The interposed fluids, on this hypothesis, have no effect as chemical agents, in producing the phenomena; they merely act as conductors of the electricity. ”

“ The vent being stopped, they fill the Cistern they have made with Water, soaking therein as much as the Earth they dig out of the Mines, as it can conveniently receive at a time, breaking the Clods, picking out the great Stones and stirring it with Shovels, till the Water is all Muddy, the gravelly stuff falling to the bottom; then they open the vent, letting out the foul Water and supplying [Pg 251] it with clean, till all the Earthly Substance be wasted away, and none but a gravelly remains at the bottom. ”

“ The door opened to the river, over the top of the room was an electrical conductor, the point of which was elevated three yards above, but divided at the ridge of the house, and ran down each side of the roof and sides of the wall into the ground. Owing to the extreme heat of the climate the air is more frequently inpregnated with electrical fluid, the clouds more frequently charged and discharged, the explosions louder, and the preparations to ward off the effect produced by it more general than in colder climates. ”

“ Lightning-Rods, when well constructed, often prevent violent discharges. Their pointed prongs at the top allow the negative electricity of the earth to pass quietly into the air to neutralize the positive in the cloud above. In case of a discharge, or stroke of lightning, the rods aid in conducting the electricity to the earth. The ends of the rods are placed deep in the earth, Fig. ”