Makers of Science: Electricity & MagnetismOxford University Press, H. Milford, 1927 - 184 pages |
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Common terms and phrases
Ampère Ampère's André Marie Ampère apparatus atom attraction called carrying current cathode rays Cavendish charged bodies chemical circuit Clerk Maxwell conduction conductor connected consists copper Davy decomposition deflection difference of potential direction disc discharge tube discovery distance earth effect electric current electric fluid electrical theory Electricity and Magnetism electrified electro-magnetic electrolyte electromotive force electrons electrostatic experimental experiments Faraday Faraday's galvanic galvanometer gases Humphry Davy hydrogen hypothesis important induced currents induction coil instrument inverse squares investigations ions iron J. J. Thomson lectures Leyden jar light lines of force Lord Kelvin magnetic field mathematical measurement metal molecular molecules needle negative observed obtained Oersted Oersted's Ohm's Ohm's Law particles passed phenomena Phil physical physicists plates poles positive quantity of electricity ratio repel researches resistance rotate Royal Institution scientific showed solution substances supposed tion Trans velocity vessel voltaic cell voltaic pile vortices wire X-rays zinc
Popular passages
Page 112 - 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.
Page 31 - It was not until about the middle of the nineteenth century that the study of Euclid became common in the secondary schools of England.
Page 158 - The phenomena in these exhausted tubes reveal to physical science a new world — a world where matter may exist in a fourth state...
Page 160 - For each chemical bond which is ruptured within an electrolyte a certain quantity of electricity traverses the electrolyte which is the same in all cases.
Page 6 - Gilbert, physician to both Elizabeth I and James I of England. Gilbert spent 17 years experimenting with magnetism and, to a lesser extent, electricity. He assembled the results of his experiments and all of the available knowledge on magnetism in the treatise De Magnete. Magneticisque Corporibus, et de Magno Magnete Tellure ("On the Magnet and Magnetic Bodies, and on That Great Magnet the Earth"). As suggested by the title, Gilbert described the Earth as a huge magnet. He introduced the term electric...
Page 160 - Now the most startling result of Faraday's law is perhaps this. If we accept the hypothesis that the elementary substances are composed of atoms, we cannot avoid concluding that eleetricity also, positive as well as negative, is divided into definite elementary portions, which behave like atoms of electricity.
Page 170 - Thus on this view we have in the cathode rays matter in a new state, a state in which the subdivision of matter is carried very much further than in the ordinary gaseous state: a state in which all matter — that is, matter derived from different sources such as hydrogen, oxygen, &c. — is of one and the same kind; this matter being the substance from which all the chemical elements are built up.
Page 49 - The {Treat tendency of the attraction of the different chemical agents by the positive and negative surfaces in the Voltaic apparatus seems to be to restore the electrical equilibrium.
Page 56 - Let us now once, as the battery is in activity, try to place the wire parallel with the needle;' as this was made, he was quite struck with perplexity by seeing the needle making a great oscillation (almost at right angles with the magnetic meridian). Then he said, 'Let...
Page 159 - This phrase, gross as it is, and out of harmony with the rest of this treatise, will enable us at least to state clearly what is known about electrolysis, and to appreciate the outstanding difficulties.