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The Victorian Age, Part Two
The Literature of Science
> Michael Faraday
History of the Inductive Sciences
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The Cambridge History of English and American Literature in 18 Volumes
Volume XIV. The Victorian Age, Part Two.
The Literature of Science
§ 4. Michael Faraday.
The most notable physicist at the beginning of the Victorian period was Michael Faraday,
who, in 1831, had begun those investigations on electricity which have altered our conceptions of the subject, and, by their applications, have revolutionised industrial science. Faraday had been brought up in humble circumstances, and his career is interesting as an illustration of the fact that, in England, no door is closed to genius. In 1812, after attending some lectures delivered by Sir Humphry Davy, he sent notes of them to Davy, asking his assistance to enable him to study science. The result was that Davy employed him as an assistant in the chemical laboratory in the Royal Institution. Here, Faradays experimental skill soon led to appreciation of his powers, and he wrote various papers on scientific questions.
Faradays earliest electrical work related to induced currents, and depended on his discovery of the fact that, if a wire in the shape of a closed curve is moved to or from another wire through which an electric current is flowing, a current is set up in the former wire which ceases so soon as the motion ceases. The induced current is caused by and depends on the motion of the one wire relative to the other. Magnetic effects can be similarly produced. Faraday went on to explain various phenomena by the action of the induced currents which he had discovered. As he pondered on possible explanations of these results, it occurred to him that all space might be filled by lines of magnetic force, every line being a closed curve passing through the magnet to which it belongs; and he pointed out that the existence of these lines was suggested by the familiar experiment of the arrangement of iron filings in such lines about a magnet from whose poles they radiate. According to this view, these induced currents were caused by the closed wire (or any conductor) being moved across lines of force in its plane of motion, and, if so, the electromotive force of an induced current would be proportional to the number of unit lines of magnetic force cut in a second by the moving wire. Now, the earth itself may be regarded as a gigantic magnet, and, hence, if a copper wire spin across the earths lines of force, we should expect currents to be produced. This was found to be the case. By these experiments, Faraday tapped vast and hitherto unknown sources of electricity. The use of dynamos as a source of mechanical power resulted from these discoveries.
These investigations were followed by experiments to show the identity in kind of electrical currents, however produced. His investigations on electrolysis attracted general attention to the subject, and led him to the remarkable conclusion that there is a certain absolute quantity of electricity associated with each atom of matter. A few years later, in 1845, he discovered another remarkable series of phenomena dependent on the fact that the plane of polarisation of light can be rotated by the action of magnets and electric currents; and, somewhat later, he discovered and investigated diamagnetic properties in bodies.
The provision of well-equipped laboratories is a modern luxury, and Faraday was exceptionally fortunate in having access to one. It is difficult to overrate his abilities as an experimental philosopher; and, though he knew but little mathematics, his conception of lines of force was essentially mathematical, and was developed later by Clerk Maxwell and other writers. At the time, however, it repelled mathematicians accustomed to the formulae and symbols with which Laplace and Poisson had made them familiar. It is interesting to see that Faraday, like Newton, refused to contemplate the possibility of action at a distance, but sought, rather, to explain the phenomena of attraction by changes in a continuous medium. He was followed at the Royal Institution by John Tyndall, whose lectures did much to excite and maintain general interest in physical questions.
While Faraday was opening new ways of regarding physical phenomena, the classical methods of Poisson were being applied with success by James MacCullagh, of Dublin, to problems of physical optics. In these investigations, MacCullagh, like his continental contemporaries, elaborated the conception of the ether as an elastic solid, and, thence, he deduced the laws of reflection and refraction; but, though his work was ingenious, many of his conclusions were vitiated by his erroneous assumption that the vibrations of plane polarised light are parallel to the plane of polarisation. Another physicist of this time whose work has been of importance was James Prescott Joule, a pupil of Dalton, who showed that heat and energy were interchangeable in definite proportions. Mention should also be made of (Sir) Charles Wheatstone, who, about 1840, brought electric telegraphy into general use. Wheatstone was a man of wide interests: he early suggested the use of spectrum analysis for chemical researches, invented stereoscopic instruments and, later, did much useful work in the construction of dynamos.
This period was rich in inventions whereby science was applied practically, as, for example, the general employment of steam-engines for locomotion, the electric telegraph and the introduction of lighting and heating by gas.
We turn from these practical applications to consider more abstract researches. Faraday was recognised as an exceptional genius, and time has strengthened the recognition of his claim to distinction; but, in general, theoretical physics had, by now, become so closely connected with mathematics that it seemed hardly possible for anyone without mathematical knowledge to make further advances in its problems. This association lasted well into the twentieth century, and the continuation and extension of Faradays work fell into the hands of mathematicians.
Before proceeding to describe the remarkable work of the school of mathematical physicists who followed Faraday, it will be convenient to mention the leading writers of this time on pure mathematics. We may begin by noting the fact that the range of pure mathematics had, ere this, grown to an extent which rendered it difficult for any man to master more than a comparatively small section of it, and,
physicists took up only such special branches of mathematics as were required for their own purposes. We should also notice that one of the striking features of this period has been the largely increased number of students of mathematical and physical science: hence, to mention only the leading writers does indirect injustice to others whose work, though not epoch-making, has been of real importance. With this caution, we proceed to name a few of those whose researches have permanently affected the development of mathematics.
In the period on which we are now entering, we find hald-a-dozen mathematiciansDe Morgan, Hamilton, Sylvester, Adams, Cayley and Smithwhose researches will always make it memorable. Hamilton and Smith were fastidious writers, and, apart from the value of their work, it is a pleasure to observe the artistic manner in which they presented it; but their pupils were few, and it was only to a select number of scholars that their writings appealed. The others were more fortunate in being connected with the great mathematical school of Cambridge. Their methods are sharply contrasted. De Morgan wrote vivaciously, and largely for non-specialists. Cayleys writings were precise and methodical, and he always sought to be exhaustive. Sylvesters papers, like his lectures, were badly constructed, impetuous and often unfinished; yet, experience proved them to be amazingly stimulating. Adamss work was elegant and highly polished. Modern pure mathematics deals so largely with abstract and special subjects that it is almost impossible to describe the conclusions in a way intelligible to laymen. It will suffice to indicate the subjects of their principal researches.
Life of Sir Walter Scott
(6 vols., 1900), vol.
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History of the Inductive Sciences
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