Hermann von Helmholtz

Hermann Ludwig Ferdinand von Helmholtz (31 August 1821 – 8 September 1894) was a German physician and physicist who made significant contributions to several widely varied areas of modern science.

The formation of scales and of the web of harmony is a product of artistic invention, and is in no way given by the natural structure or by the natural behaviour of our hearing, as used to be generally maintained hitherto.
- The Theory of Sound (1862)

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

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 Physiological Causes of Harmony" (1857), p. 81

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

There is a kind, I might almost say, of artistic satisfaction, when we are able to survey the enormous wealth of Nature as a regularly ordered whole — a kosmos, an image of the logical thought of our own mind.
- "On the Conservation of Force" (1862), p. 279

The last decades of scientific development have led us to the recognition of a new universal law of all natural phenomena, which, from its extraordinarily extended range, and from the connection which it constitutes between natural phenomena of all kinds, even of the remotest times and the most distant places, is especially fitted to give us an idea of what I have described as the character of the natural sciences, which I have chosen as the subject of this lecture.
- "On the Conservation of Force" (1862), p. 279

The quantity of force which can be brought into action in the whole of Nature is unchangeable, and can neither be increased nor diminished.
- Summarizing the Law of Conservation of Force, in "On the Conservation of Force" (1862), p. 280

In speaking of the work of machines and of natural forces we must, of course, in this comparison eliminate anything in which activity of intelligence comes into play. The latter is also capable of the hard and intense work of thinking, which tries a man just as muscular exertion does.
- "On the Conservation of Force" (1862), p. 280

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

According to Sir W. Thomson's theory of Vortex Atoms, the substance of which the molecule consists is a uniformly dense plenum, the properties of which are those of a perfect fluid, the molecule itself being nothing but a certain motion impressed on a portion of this fluid, and this motion is shewn, by a theorem due to Helmholtz, to be as indestructible as we believe a portion of matter to be.
- James Clerk Maxwell, "Introductory Lecture on Experimental Physics," The Scientific Papers of James Clerk Maxwell (1890) Vol.2

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"Hermann von Helmholtz" (Obituary). Royal Society (Great Britain). (1894). Proceedings of the Royal Society of London. London: Printed by Taylor and Francis.
"Hermann von Helmholtz" by Leo Koenigsberger (Oxford: Clarendon press, 1906) from Internet Archive
"Hermann von Helmholtz" article by Lydia Patton, Stanford Encyclopedia of Philosophy
"Hermann von Helmholtz", at the MacTutor History of Mathematics archive
J. G. McKendrick Hermann Ludwig Ferdinand von Helmholtz (London : Unwin, 1899)
On the Conservation of Force Introduction to a Series of Lectures Delivered at Carlsruhe in the Winter of 1862–1863, English translation
On the Sensations of Tone as a Physiological Basis for the Theory of Music (downloadable from Google Books) Fourth Edition, By Hermann von Helmholtz, Alexander John Ellis, Published by Longmans, Green, 1912, 575 pages
Treatise on Physiological Optics 1910, three volumes. English translation by Optical Society of America (1924–5).
Popular lectures on scientific subjects 1885
Popular lectures on scientific subjects second series, 1908
Biography, bibliography and access to digital sources in the Virtual Laboratory] of the Max Planck Institute for the History of Science]

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