Fuente: Faraday Lecture (1881). Citado en On the Modern Development of Faraday's Conception of Electricity, Journal of the Chemical Society 1881, 39, 290.
Frases célebres de Hermann von Helmholtz
Enunciado de la Ley de Conservación de la Fuerza.
Fuente: "Sobre la conservación de la fuerza" (1862), pág. 280
Fuente: On the Modern Development of Faraday's Conception of Electricity, Journal of the Chemical Society 1881, 39, 302.
Fuente: The Aim and Progress of Physical Science (1869). Popular Lectures on Scientific Subjects (1873), 369.
Fuente: On Thought in Medicine (1877). Trad. E. Atkinson, Popular Lectures on Scientific Subjects (1881), 234.
Hermann von Helmholtz: Frases en inglés
"On the Physiological Causes of Harmony" (1857), p. 81
Popular Lectures on Scientific Subjects (1881)
Contexto: As you are aware, no perceptions obtained by the senses are merely sensations impressed on our nervous systems. A peculiar intellectual activity is required to pass from a nervous sensation to the conception of an external object, which the sensation has aroused. The sensations of our nerves of sense are mere symbols indicating certain external objects, and it is usually only after considerable practice that we acquire the power of drawing correct conclusions from our sensations respecting the corresponding objects.
"On the Physiological Causes of Harmony" (1857), p. 81
Popular Lectures on Scientific Subjects (1881)
Contexto: As you are aware, no perceptions obtained by the senses are merely sensations impressed on our nervous systems. A peculiar intellectual activity is required to pass from a nervous sensation to the conception of an external object, which the sensation has aroused. The sensations of our nerves of sense are mere symbols indicating certain external objects, and it is usually only after considerable practice that we acquire the power of drawing correct conclusions from our sensations respecting the corresponding objects.
"On the Conservation of Force" (1862), p. 278
Popular Lectures on Scientific Subjects (1881)
Contexto: Every great deed of which history tells us, every mighty passion which art can represent, every picture of manners, of civic arrangements, of the culture of peoples of distant lands or of remote times, seizes and interests us, even if there is no exact scientific connection among them. We continually find points of contact and comparison in our own conceptions and feelings; we get to know the hidden capacities and desires of the mind, which in the ordinary peaceful course of civilised life remain unawakened.
It is not to be denied that, in the natural sciences, this kind of interest is wanting. Each individual fact, taken by itself, can indeed arouse our curiosity or our astonishment, or be useful to us in its practical applications. But intellectual satisfaction we obtain only from a connection of the whole, just from its conformity with law.
"On the Conservation of Force" (1862), p. 278
Popular Lectures on Scientific Subjects (1881)
Contexto: Every great deed of which history tells us, every mighty passion which art can represent, every picture of manners, of civic arrangements, of the culture of peoples of distant lands or of remote times, seizes and interests us, even if there is no exact scientific connection among them. We continually find points of contact and comparison in our own conceptions and feelings; we get to know the hidden capacities and desires of the mind, which in the ordinary peaceful course of civilised life remain unawakened.
It is not to be denied that, in the natural sciences, this kind of interest is wanting. Each individual fact, taken by itself, can indeed arouse our curiosity or our astonishment, or be useful to us in its practical applications. But intellectual satisfaction we obtain only from a connection of the whole, just from its conformity with law.
"On the Physiological Causes of Harmony" (1857), p. 81
Popular Lectures on Scientific Subjects (1881)
Contexto: Now it is a universal law of the perceptions obtained through the senses that we pay only so much attention to the sensations actually experienced as is sufficient for us to recognise external objects. In this respect we are very one-sided and inconsiderate partisans of practical utility; far more so indeed than we suspect. All sensations which have no direct reference to external objects, we are accustomed, as a matter of course, entirely to ignore, and we do not become aware of them till we make a scientific investigation of the action of the senses, or have our attention directed by illness to the phenomena of our own bodies. Thus we often find patients, when suffering under a slight inflammation of the eyes, become for the first time aware of those beads and fibres known as mouches volantes swimming about within the vitreous humour of the eye, and then they often hypochondriacally imagine all sorts of coming evils, because they fancy that these appearances are new, whereas they have generally existed all their lives.
"On the Conservation of Force" (1862), p. 280
Popular Lectures on Scientific Subjects (1881)
Contexto: The external work of man is of the most varied kind as regards the force or ease, the form and rapidity, of the motions used on it, and the kind of work produced. But both the arm of the blacksmith who delivers his powerful blows with the heavy hammer, and that of the violinist who produces the most delicate variations in sound, and the hand of the lacemaker who works with threads so fine that they are on the verge of the invisible, all these acquire the force which moves them in the same manner and by the same organs, namely, the muscles of the arm. An arm the muscles of which are lamed is incapable of doing any work; the moving force of the muscle must be at work in it, and these must obey the nerves, which bring to them orders from the brain. That member is then capable of the greatest variety of motions; it can compel the most varied instruments to execute the most diverse tasks.
"On the Conservation of Force" (1862), p. 280
Popular Lectures on Scientific Subjects (1881)
Contexto: The external work of man is of the most varied kind as regards the force or ease, the form and rapidity, of the motions used on it, and the kind of work produced. But both the arm of the blacksmith who delivers his powerful blows with the heavy hammer, and that of the violinist who produces the most delicate variations in sound, and the hand of the lacemaker who works with threads so fine that they are on the verge of the invisible, all these acquire the force which moves them in the same manner and by the same organs, namely, the muscles of the arm. An arm the muscles of which are lamed is incapable of doing any work; the moving force of the muscle must be at work in it, and these must obey the nerves, which bring to them orders from the brain. That member is then capable of the greatest variety of motions; it can compel the most varied instruments to execute the most diverse tasks.
Summarizing the Law of Conservation of Force, in "On the Conservation of Force" (1862), p. 280
Popular Lectures on Scientific Subjects (1881)
"On the Conservation of Force" (1862), p. 279
Popular Lectures on Scientific Subjects (1881)
"On the Conservation of Force" (1862), p. 280
Popular Lectures on Scientific Subjects (1881)
"On the Conservation of Force" (1862), p. 279
Popular Lectures on Scientific Subjects (1881)
The Theory of Sound (1862)