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Academy acoustics action after-images already alteration anatomy apparatus appeared artist axioms Berlin bodies Bois Bois-Reymond Bonn chemical colours combination tones conception conclusions conductors connexion Conservation of Energy corresponding determined discovery distance electrical currents electrodynamic electromotive electromotive force equations excitation experimental experiments expressed external fact father fluid forces friends fundamental galvanometer gave geometry give given heat Heidelberg Helmholtz Hertz hypothesis ideas illumination important interesting investigations Johannes Muller Kirchhoff knowledge Konigsberg later lecture letter light Lord Kelvin Ludwig magnetic magnitude mathematical measure mechanical ments method motion muscle natural science nerve object observations ophthalmoscope over-tones particles perception phenomena philosophical physicists physics Physiological Optics ponderable Pontresina position possible potential Potsdam principle problems processes produced Professor published question rays regard relations retina rotation scientific sensation space spectrum surface theoretical theory theory of colour Thomson tion velocity vibrations viva wife writes
Page 145 - Helmholtz that Thomson had made a deep impression on him. " I expected to find the man, who is one of the first mathematical physicists of Europe, somewhat older than myself, and was not a little astonished when a very juvenile and exceedingly fair youth, who looked quite girlish, came forward. He had taken a room for me close by, and made me fetch my things from the hotel and put up there. He is at Kreutznach for his wife's health.
Page 224 - How his students understand him, without keeping him as strictly to the subject as I ventured to do, is a puzzle to me ; still, there were numbers of students in the laboratory hard at work, and apparently quite understanding what they were about. Thomson's experiments, however, did for my new hat. He had thrown a heavy metal disk into very rapid rotation ; and it was revolving on a point. In order to show me how rigid it became in its rotation, he hit it with an iron hammer, but the disk resented...
Page 223 - ... gets through with his subject. In the intervals I have seen a quantity of new and most ingenious apparatus and experiments of W. Thomson, which made the two days very interesting. He thinks so rapidly, however, that one has to get at the necessary information about the make of the instruments, etc., by a long string of questions, which he shies at. How his students understand him, without keeping him as strictly to the subject as I ventured to do, is a puzzle to me ; still, there were numbers...
Page 181 - ... then, whether by taking thought or from luck, discovers a new track that leads him on a little, till at length when he reaches the summit he finds to his shame that there is a royal road, by which he might have ascended, had he only had the wits to find the right approach to it. In my works I naturally said nothing about my mistakes to the reader, but only described the made track by which he may now reach the same heights without difficulty.
Page 208 - Was, von Menschen nicht gewußt Oder nicht bedacht, Durch das Labyrinth der Brust Wandelt in der Nacht.
Page 75 - ... invention, late in 1850, of the opthalmoscope, an instrument which renders it possible to examine the retina of the living eye. Helmholtz says: While preparing my lectures I hit upon the invention of the opthalmoscope, and then on the method of measuring the velocity of nervous impulses. The opthalmoscope became the most popular of my scientific achievements, but I have already pointed out to the oculists that good fortune had more to do with it than merit. I had to explain the theory of the...
Page 77 - I attribute my subsequent success to the fact that circumstances had fortunately planted me with some knowledge of geometry and training in physics among the doctors, where physiology presented a virgin soil of the utmost fertility, while, on the other hand, I was led by my acquaintance with the phenomena of life to problems and points of view that are beyond the scope of pure mathematics and physics.
Page 349 - I did Thomson an injustice in supposing him to be wholly immersed in technical work ; he was full of speculations as to the original properties of bodies, some of which were very difficult to follow ; and, as you know, he will not stop for meals or any other consideration.
Page 39 - Gay-Lussac regarding the volumes of gases, — are evidently nothing more than general ideas by which the various phaenomena which belong to them are connected together. The finding out of these is the office of the experimental portion of our science. The theoretic portion seeks, on the contrary, to evolve the unknown causes of the processes from the visible actions which they present; it seeks to comprehend these processes according to the laws of causality. We are justified, and indeed impelled...
Page 214 - Thomson had told Helmholtz of his purpose, and in 1862 Helmholtz wrote him: Your undertaking to* write a text-book of natural philosophy Is very praiseworthy, but will be exceedingly tedious. At the same time I hope it will suggest ideas to you for much valuable work. It is in writing a book like that that one best appreciates the gaps still left in science.