The Practical Applications of Electricity: A Series of Lectures Delivered at the Institution of Civil Engineers, Session 1882-83Institution of Civil Engineers (Great Britain), Sir William Henry Preece, Sir Frederick Joseph Bramwell, Charles William Siemens, John Hopkinson, Sir Frederick Augustus Abel The Institution, 1884 - 181 Seiten |
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Häufige Begriffe und Wortgruppen
absolute system alternate current alternate-current Ampères apparatus application of electricity armature arrangements Bell British Association unit cable carbon cent centimetre charges circuit coil conducting power conductor connected considerable conveyed copper wire current of electricity current passing diagram direction disk distance dynamo dynamo-electric dynamo-machine Edison effect efficiency electric current electric machine electrical energy electrical resistance electro-magnetic electromotive force employed engine experiments exploding agent firing Frederick Bramwell frictional frictional electric galvanometer give gunpowder gutta-percha heat high-tension fuze ignition incandescent increase instrument insulated iron JAMES BRUNLEES lamp lecture length Leyden jar light line wire Lord Rayleigh magnetic field magneto-electric matter mean solar second mechanical ments metal motion needle obtained operations plate platinum poles potential practical produced purposes receiver reckoning resistance result round Siemens unit simple simultaneous sound station submarine mines success telegraph telephone temperature tion torpedoes transmitter universal-gravitation vary velocity vibrations volts Watts wire Woolwich zinc
Beliebte Passagen
Seite 149 - I often say that when you can measure what you are speaking about and express it in numbers, you know something about it ; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind : it may be the beginning of knowledge, but you have scarcely in your thoughts advanced to the stage of science whatever the matter may be.
Seite 149 - In physical science a first essential step in the direction of learning any subject is to find principles of numerical reckoning and methods for practically measuring some quality connected with it. I often say that when you can measure what you are speaking about and express it in numbers, you know something about it ; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind...
Seite 32 - When, therefore, a permanent magnet is caused to vibrate in front of the pole of an electro-magnet an undulatory current of electricity is induced in the coils of the electro-magnet, the undulations of which correspond, in rapidity of succession, to the vibrations of the magnet, in polarity to the direction of its motion, and in intensity to the amplitude of its vibration.
Seite 151 - There cannot be a greater mistake, than that of looking superciliously upon practical applications of science.
Seite 158 - I know, to the intelligent treatment of dynamic problems and their applications to both scientific and engineering matters. The system of absolute reckoning of force by Gauss cannot be too much commended, as a great and important practical improvement in the fundamental science of engineering and physics, the science of dynamics. It consists simply in defining the unit of force as that force which, acting on a unit of mass for a unit of time, generates a velocity equal to the unit of velocity. It...
Seite 153 - This committee worked for nearly another ten years through the whole field of electro-magnetic and electro-static measurement, but chiefly on standards of electric resistance, until in its final report, presented to the Exeter meeting in August 1869, it fairly launched the absolute system for general use; with arrangements for the 1 Leipsig, 1852.
Seite 151 - It seems, indeed, as if the commercial requirements of the application of electricity to lighting, and other uses of every-day life, were destined to cause an advance of the practical science of electric measurement, not less important and valuable in the higher region of scientific investigation, than that which, from twenty to thirty years ago, was brought about by the practical requirements of submarine telegraphy.
Seite 131 - ... to one extremity, the other being buried. About eleven months afterwards the fuze was exploded by a charge induced in the conductor during a very heavy thunderstorm. In consequence of such difficulties as these experienced in the special application of the high-tension fuzes to submarine purposes, the production of comparatively sensitive low-tension fuzes, of much greater uniformity of resistance than those employed in former years, was made the subject of an elaborate experimental investigation...
Seite 111 - ... at different periods, the difficulties attending the transport and proper preservation of the battery and materials required for its use, the dependence for success upon care and experience in preparing and preserving the batteries, and the very considerable increase which it is necessary to make in the power of the battery when the operations to be performed involve the simultaneous explosion of a number of charges, or the ignition of gunpowder at very considerable distances from the battery.
Seite 5 - ... individualism and the highest success in teaching in the lower grades, a larger proportionate teaching force is imperative, the need of improvement in the quality of the work is quite as urgent. No class in the community know so well as the superintendents, whom I have the honor to address, that during the last few years very great improvements have been made in the work of the elementary schools — improvements which many of those whose work is mainly in the higher grades fail to realize or...