Electricity

“ For electricity is distinguished from all other power-supplying natural forces, living or otherwise, precisely in this, that it can be concentrated spatially with the aid of a physical carrier whose material bulk is insignificant compared with the energy supplied.
Through this property of electricity it has been possible for man to extend the range of his activity in all directions, far and near. ”

“ We have talked about making electricity work when it flows in a steady stream, and everybody knows that it makes lights glow, makes toasters and electric stoves hot, and heats electric irons. But did it ever strike you as remarkable that the same electricity that flows harmlessly through the wires in your house without heating them, suddenly makes the wire in your toaster or the filament in your incandescent lamp glowing hot? The insulation is not what keeps the wire cool, as you can see by the next experiment. ”

“ When we speak therefore of a body being charged with a quantity of electricity we mean simply that the body is electrified, and that the electrification is vitreous or resinous according as is positive or negative. ”

“ THE BIRTH OF THE SCIENCE OF ELECTRICITY Although the science of electricity is of comparatively recent date, electricity itself has existed from the beginning of the world. There can be no doubt that man’s introduction to electricity was brought about through the medium of the thunderstorm, and from very early times come down to us records of the terror inspired by thunder and lightning, and of the ways in which the ancients tried to account for the phenomena. ”

“ Now, in all these enjoyable and elevating features which characterize modern intellectual development, electricity, the expansion of the science of electricity, has been a most potent factor. Electrical science has revealed to us the true nature of light, has provided us with innumerable appliances and instruments of precision, and has thereby vastly added to the exactness of our knowledge. ”

“ I take it that we may safely regard the evolution of electricity as one of the ways in which force exhibits itself, that, in other words, when work is performed electricity may result. When two bodies are rubbed together, electricity is produced, so also is it when two connected metals are immersed in water and one of them is dissolved, or when one of the junctions of two metals is raised to a higher temperature than the other junction. ”

“ After demonstrating the practicability of this method of transmission, the thought naturally occurred to me to use the earth as a conductor, thus dispensing with all wires. Whatever electricity may be, it is a fact that it behaves like an incompressible fluid, and the earth may be looked upon as an immense reservoir of electricity, which, I thought, could be disturbed effectively by a properly designed electrical machine. Accordingly, my next efforts were directed toward perfecting a special apparatus which would be highly effective in creating a disturbance of electricity in the earth. ”

“ Here we have one line of advance from candles and oil lamps to gas, and from gas to electricity; and we can recognize many other threads of advance all converging upon electricity. We produce heat and light by electricity. We transmit intelligence by the telegraph and telephone, and we use electricity as a motive power. In fact, we have fairly entered upon an electrical age, and it is obvious that the electrical engineer will be much in demand in the future. Those of you who devote yourselves to electrical subjects will certainly find a place and room to work. ”

“ To the engineer and to those who desire to know the trend of electrical development, the most interesting exhibit at the Fair will doubtless be the apparatus designed to show the long-distance transmission of power. Almost at the beginning of the modern electrical era, dreams were indulged in of the command which electricity was to give us of the natural sources of power. ”

“ In order, however, to carry the proof of the identity of these forms of energy beyond the sphere of vague analogy, we must follow up electricity far beyond the simple manifestations of the glass rod and sealing-wax, and pursue it to its origin, in the transformations of chemical action and mechanical work, in the voltaic battery, the electric telegraph, the telephone, and the dynamo. ”

“ I have spoken here of the generation of a greater or less amount of electricity, but in reality it would be more correct to speak simply of a change in the electrical condition of the substance. Electricians speak of positive and negative electricity as though there actually were two distinct forms of this peculiar property of matter. But it may be questioned whether it would not be more correct to speak of electricity as we do of heat. ”

“ You will remember that when we explained what "resistance" meant, we told you that electricity would always take the easiest path, and while part of it will flow in a small wire, the largest portion will take an easier path if it can get to something larger that is a metallic substance. Electricity will only flow easily through anything that is made of metal. You will also remember that you learned that when electricity took a short cut to get away from its proper path it was called a short circuit. ”

“ Now, electricity is a very exact science. There is no mere theory about it; and a unit is a definite quantity of power, known in that science as a “kilowatt hour.” Thus, a kilowatt, or 1,000 watts, is the equivalent in measured work of 11⁄3 horse-power, equal to the lifting of 44,000 lbs. per minute, or the doing of so many units of work, either electric lighting, heating, machinery driving, or traction. ”

“ All bodies conduct electricity in the same manner from metals to lac and gases, but in very different degrees.
445. Conducting power is in some bodies powerfully increased by heat, and in others diminished, yet without our perceiving any accompanying essential electrical difference, either in the bodies or in the changes occasioned by the electricity conducted.
446. A numerous class of bodies, insulating electricity of low intensity, when solid, conduct it very freely when fluid, and are then decomposed by it. ”

“ Such an extension of the practical applications of electricity as we have indicated implies a corresponding development of the science itself; and, indeed, the history of electricity during the present century is a continuous record of brilliant discoveries made by men of rare and commanding genius—such as Davy, Ampère, and Faraday. ”

“ The power of the falling water is transformed into electricity. Electricity and heat are both vibratory motions of the ether; science has found that the vibrations known as electricity can be changed into the vibrations known as heat. Accordingly, a thousand horse-power from the mighty river is conveyed as electricity over a copper wire, changed into heat and light between the tips of carbon electrodes, and there works its wonders. In principle the electrical furnace is identical with the electric light. ”

“ Electricity, on the other hand, is invisible, cannot be poured into cans or tanks, has no odor, and, therefore, nobody knows just what it is. We can only study the effects of electricity, and the wires, coils, and similar apparatus in which it is present. It is for this reason that an air of mystery surrounds electrical things, especially to the man who has not made a special study of the subject. ”

“ In 1783 he published in London ‘Experiments and Observations on Electricity,’ a work in which he described some of the effects which an electrical power is capable of producing on conducting substances, similar effects of the same power on electric bodies themselves, and observations on the air, electric repulsion, the electrified cup, and the analogy between electricity and magnetism. ”

“ In most theories on the subject, Electricity is treated as a substance, but inasmuch as there are two kinds of electrification which, being combined, annul each other, and since we cannot conceive of two substances annulling each other, a distinction has been drawn between Free Electricity and Combined Electricity. ”

“ Electricity was not then utilised for locomotion either on land or sea, or for raising ponderous bodies to an immense height, or in the various products of manufacture and art, or, in short, for any of the almost innumerable purposes where the various electricities are now employed, either separately or in combination. ”

“ Contains a clear and concise account of the various forms in which electricity is used at the present day, and the working of the telephone, wireless telegraphy, tramcars, and dynamos is explained with the greatest possible lucidity, while the marvels of the X-rays and of radium receive their due notice. Now that electricity plays such an all-important part in our daily life, such a book as this should be in the hands of every boy. ”

“ Substances which, like an air gap, interfere with the flow of electricity are called non-conductors, or, more commonly, insulators. Substances which, like the earth, the human body, and all other moist objects, conduct electricity are conductors. If the telephone and electric light wires in our houses were not insulated by a covering of thread, or cloth, or other non conducting material, the electricity would escape into surrounding objects instead of flowing through the wire and producing sound and light. ”

“ Electricity as an illuminant and for all possible purposes is so cheaply procured as to be within the means of all requiring its use. Throughout the irrigated belt and on most portions of Ento there are Stations where thoroughly trained persons attend to the production and distribution of electric currents, and so valued is life that accidents are of very rare occurrence. ”

“ Speaking of electricity as an energetic source of light, of heat, of chemical action, and of mechanical power—prescient words in those days—he said it was only necessary to know the conditions under which its various effects may be most economically and energetically manifested to enable us to determine whether the high expectations formed in many quarters of some of its daily increasing practical applications are founded on reasonable hope or on fallacious conjecture. ”

“ I have said that electricity can be generated in many ways. It may be said, indeed, that every change in the condition of a substance, whether from mechanical causes, as, for instance, a blow, a series of small blows, friction, and so forth, or from change of temperature, moisture, and the like, or from the action of light, or from chemical processes, results in the development of more or less electricity. ”

“ There is, however, another reason which warrants us in asserting that electricity, as a physical quantity, synonymous with the total electrification of a body, is not, like heat, a form of energy. An electrified system has a certain amount or energy, and this energy can be calculated by multiplying the quantity of electricity in each of its parts by another physical quantity, called the Potential, of that part, and taking half the sum of the products. ”

“ When I told that audience that no electrical generator generates electricity, because electricity was made by God and, according to Faraday, its quantity in the universe is constant, and that for every positive charge there is an equal negative one, most members of my audience were inclined to think that I was talking metaphysics. “Then what does it generate?” asked one of282 my hearers. I answered: “It generates motion of electricity, and by that motion it furnishes us with means of doing useful work like telegraphy, telephony, and electrical lighting.” ”

“ The electrical transmission of power is exemplified in everything which is based on the generation of electricity. The ordinary electric light is power coming from a generator in the building or a public street-dynamo.
However, when we talk in general terms of electric transmission we mean the transmission of energy on a large scale by means of overhead or underground conductors to a considerable distance and the transformation of this energy into light and heat and chemical or mechanical power to carry on the processes of work and industry. ”

“ While the nature and source of electricity are a mystery, and a constant challenge to the inquirer, many things about it have become known—thus, it is positively assured that electricity never manifests itself except when there is some mechanical disturbance in ordinary matter, and every exhibition of electricity in any of its multitudinous ways may always be traced back to a mass of matter. ”

“ We may thus make use of a small nucleus of electricity, to assist us in procuring an unlimited supply, for in the above process the electricity of the prime conductor remains unaltered, and we may repeat the operation as often as we like, and gather together a very large quantity of electricity, without finally altering the electricity of the prime conductor, but not, however, without the expenditure of an equivalent amount of energy, in the shape of actual work. ”

“ This attractive Power of Electricity acts not only upon Non-electrics, as Leaf-Gold, Silver, Thread, and such like, but also upon originally Electrics, as Silk, dry Feathers, little Pieces of Glass and Resin; it attracts all Bodies, that are not of the same Standard of Electricity, (if I may be allowed the Expression) as the excited Body from which it proceeds. I have found no Body however dense, whose Pores are not pervious to Electricity by a proper Management, not even Gold itself. ”

“ Another mode of explanation is given by those who maintain, in opposition to Franklin, that positive and negative electricity are either two distinct fluids, or else vibrations of the same fluid—the positive electricity always rushing out of a body, and the negative always rushing in. Those who maintain this hypothesis endeavour to support it by the easy solution which they affirm it gives to the phenomena of electric attraction and repulsion. ”