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Who said: “I have no satisfaction in formulas unless I feel their arithmetical magnitude.”
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Home > Category Index for Science Quotations > Category Index P > Category: Propagation

Propagation Quotes (15 quotes)

[After the flash of the atomic bomb test explosion] Fermi got up and dropped small pieces of paper … a simple experiment to measure the energy liberated by the explosion … [W]hen the front of the shock wave arrived (some seconds after the flash) the pieces of paper were displaced a few centimeters in the direction of propagation of the shock wave. From the distance of the source and from the displacement of the air due to the shock wave, he could calculate the energy of the explosion. This Fermi had done in advance having prepared himself a table of numbers, so that he could tell immediately the energy liberated from this crude but simple measurement. … It is also typical that his answer closely approximated that of the elaborate official measurements. The latter, however, were available only after several days’ study of the records, whereas Fermi had his within seconds.
In Enrico Fermi: Physicist (1970), 147-148.
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At the entrance to the observatory Stjerneborg located underground, Tycho Brahe built a Ionic portal. On top of this were three sculptured lions. On both sides were inscriptions and on the backside was a longer inscription in gold letters on a porfyr stone: Consecrated to the all-good, great God and Posterity. Tycho Brahe, Son of Otto, who realized that Astronomy, the oldest and most distinguished of all sciences, had indeed been studied for a long time and to a great extent, but still had not obtained sufficient firmness or had been purified of errors, in order to reform it and raise it to perfection, invented and with incredible labour, industry, and expenditure constructed various exact instruments suitable for all kinds of observations of the celestial bodies, and placed them partly in the neighbouring castle of Uraniborg, which was built for the same purpose, partly in these subterranean rooms for a more constant and useful application, and recommending, hallowing, and consecrating this very rare and costly treasure to you, you glorious Posterity, who will live for ever and ever, he, who has both begun and finished everything on this island, after erecting this monument, beseeches and adjures you that in honour of the eternal God, creator of the wonderful clockwork of the heavens, and for the propagation of the divine science and for the celebrity of the fatherland, you will constantly preserve it and not let it decay with old age or any other injury or be removed to any other place or in any way be molested, if for no other reason, at any rate out of reverence to the creator’s eye, which watches over the universe. Greetings to you who read this and act accordingly. Farewell!
(Translated from the original in Latin)
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First, by what means it is that a Plant, or any Part of it, comes to Grow, a Seed to put forth a Root and Trunk... How the Aliment by which a Plant is fed, is duly prepared in its several Parts ... How not only their Sizes, but also their Shapes are so exceedingly various ... Then to inquire, What should be the reason of their various Motions; that the Root should descend; that its descent should sometimes be perpendicular, sometimes more level: That the Trunk doth ascend, and that the ascent thereof, as to the space of Time wherein it is made, is of different measures... Further, what may be the Causes as of the Seasons of their Growth; so of the Periods of their Lives; some being Annual, others Biennial, others Perennial ... what manner the Seed is prepared, formed and fitted for Propagation.
'An Idea of a Philosophical History of Plants', in The Anatomy of Plants With an Idea of a Philosophical History of Plants and Several Other Lectures Read Before the Royal Society (1682), 3-4.
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Fourier’s Theorem … is not only one of the most beautiful results of modern analysis, but it may be said to furnish an indispensable instrument in the treatment of nearly every recondite question in modern physics. To mention only sonorous vibrations, the propagation of electric signals along a telegraph wire, and the conduction of heat by the earth’s crust, as subjects in their generality intractable without it, is to give but a feeble idea of its importance.
In William Thomson and Peter Guthrie Tait, Treatise on Natural Philosophy (1867), Vol. 1, 28.
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If an organised body is not in the situation and circumstances best adapted to its sustenance and propagation, then, in conceiving an indefinite variety among the individuals of that species, we must be assured, that, on the one hand, those which depart most from the best adapted constitution, will be most liable to perish, while, on the other hand, those organised bodies, which most approach to the best constitution for the present circumstances, will be best adapted to continue, in preserving themselves and multiplying the individuals of their race.
In An Investigation into the Principles of Knowledge (1794, 1999), Vol. 2, 501.
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In order that an inventory of plants may be begun and a classification of them correctly established, we must try to discover criteria of some sort for distinguishing what are called “species”. After a long and considerable investigation, no surer criterion for determining species had occurred to me than distinguishing features that perpetuate themselves in propagation from seed. Thus, no matter what variations occur in the individuals or the species, if they spring from the seed of one and the same plant, they are accidental variations and not such as to distinguish a species. For these variations do not perpetuate themselves in subsequent seeding. Thus, for example, we do not regard caryophylli with full or multiple blossoms as a species distinct from caryophylli with single blossoms, because the former owe their origin to the seed of the latter and if the former are sown from their own seed, they once more produce single-blossom caryophylli. But variations that never have as their source seed from one and the same species may finally be regarded as distinct species. Or, if you make a comparison between any two plants, plants which never spring from each other's seed and never, when their seed is sown, are transmuted one into the other, these plants finally are distinct species. For it is just as in animals: a difference in sex is not enough to prove a difference of species, because each sex is derived from the same seed as far as species is concerned and not infrequently from the same parents; no matter how many and how striking may be the accidental differences between them; no other proof that bull and cow, man and woman belong to the same species is required than the fact that both very frequently spring from the same parents or the same mother. Likewise in the case of plants, there is no surer index of identity of species than that of origin from the seed of one and the same plant, whether it is a matter of individuals or species. For animals that differ in species preserve their distinct species permanently; one species never springs from the seed of another nor vice versa.
Historia Plantarum (1686), Vol. 1, 40. Trans. Edmund Silk. Quoted in Barbara G. Beddall, 'Historical Notes on Avian Classification', Systematic Zoology (1957), 6, 133-4.
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Life was born and propagates itself on the earth as a solitary pulsation.
In Teilhard de Chardin and Sara Appleton-Weber (trans.), The Human Phenomenon (1999, 2003), 60. Originally published in French as Le Phénomene Humain (1955).
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My theory of electrical forces is that they are called into play in insulating media by slight electric displacements, which put certain small portions of the medium into a state of distortion which, being resisted by the elasticity of the medium, produces an electromotive force ... I suppose the elasticity of the sphere to react on the electrical matter surrounding it, and press it downwards.
From the determination by Kohlrausch and Weber of the numerical relation between the statical and magnetic effects of electricity, I have determined the elasticity of the medium in air, and assuming that it is the same with the luminiferous ether I have determined the velocity of propagation of transverse vibrations.
The result is
193088 miles per second
(deduced from electrical & magnetic experiments).
Fizeau has determined the velocity of light
= 193118 miles per second
by direct experiment.
This coincidence is not merely numerical. I worked out the formulae in the country, before seeing Webers [sic] number, which is in millimetres, and I think we have now strong reason to believe, whether my theory is a fact or not, that the luminiferous and the electromagnetic medium are one.
Letter to Michael Faraday (19 Oct 1861). In P. M. Harman (ed.), The Scientific Letters and Papers of James Clerk Maxwell (1990), Vol. 1, 1846-1862, 684-6.
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One of the grandest generalizations formulated by modern biological science is that of the continuity of life; the protoplasmic activity within each living body now on earth has continued without cessation from the remote beginnings of life on our planet, and from that period until the present no single organism has ever arisen save in the form of a bit of living protoplasm detached from a pre-existing portion; the eternal flame of life once kindled upon this earth has passed from organism to organism, and is still, going on existing and propagating, incarnated within the myriad animal and plant forms of everyday life.
In History of the Human Body (1919), 1.
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That many very remarkable change and involuntary motions are sudden produced in the body by various affections of the mind, is undeniably evinced from a number of facts. Thus fear often causes a sudden and uncommon flow of pale urine. Looking much at one troubled with sore eyes, has sometimes affected the spectator with the same disease.—Certain sounds cause a shivering over the whole body.—The noise of a bagpipe has raised in some persons an inclination to make urine.—The sudden appearance of any frightful object, will, in delicate people, cause an uncommon palpitation of the heart.—The sight of an epileptic person agitated with convulsions, has brought on an epilepsy; and yawning is so very catching, as frequently to be propagated through whole companies.
In An Essay on the Vital and Other Involuntary Motions of Animals (1751), 253-254.
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The capital ... shall form a fund, the interest of which shall be distributed annually as prizes to those persons who shall have rendered humanity the best services during the past year. ... One-fifth to the person having made the most important discovery or invention in the science of physics, one-fifth to the person who has made the most eminent discovery or improvement in chemistry, one-fifth to the one having made the most important discovery with regard to physiology or medicine, one-fifth to the person who has produced the most distinguished idealistic work of literature, and one-fifth to the person who has worked the most or best for advancing the fraternization of all nations and for abolishing or diminishing the standing armies as well as for the forming or propagation of committees of peace.
From will (27 Nov 1895), in which he established the Nobel Prizes, as translated in U.S. Dept. of Commerce, Consular Reports, Issues 156-159 (1897), 331.
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The velocity of light is one of the most important of the fundamental constants of Nature. Its measurement by Foucault and Fizeau gave as the result a speed greater in air than in water, thus deciding in favor of the undulatory and against the corpuscular theory. Again, the comparison of the electrostatic and the electromagnetic units gives as an experimental result a value remarkably close to the velocity of light–a result which justified Maxwell in concluding that light is the propagation of an electromagnetic disturbance. Finally, the principle of relativity gives the velocity of light a still greater importance, since one of its fundamental postulates is the constancy of this velocity under all possible conditions.
Studies in Optics (1927), 120.
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There is, it appears, a conspiracy of scientists afoot. Their purpose is to break down religion, propagate immorality, and so reduce mankind to the level of brutes. They are the sworn and sinister agents of Beelzebub, who yearns to conquer the world, and has his eye especially upon Tennessee.
[Report on the Scopes Monkey Trial.]
Baltimore Evening Sun (11 Jul 1925). In H.L. Mencken, S. T. Joshi (Ed.), H.L. Mencken on Religion (2002), 178.
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This is the patent-age of new inventions
For killing bodies, and for saving souls,
All propagated with the best intentions;
Sir Humphrey Davy's lantern, by which coals
Are safely mined for in the mode he mentions,
Tombuctoo travels, voyages to the Poles,
Are ways to benefit mankind, as true,
Perhaps, as shooting them at Waterloo.
Don Juan (1819, 1858), Canto I, CXXXII, 36. Although aware of scientific inventions, the poet seemed to view them with suspicion. Davy invented his safety lamp in 1803. Sir W.E. Parry made a voyage to the Arctic Regions (4 Apr to 18 Nov 1818).
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We are machines built by DNA whose purpose is to make more copies of the same DNA. ... This is exactly what we are for. We are machines for propagating DNA, and the propagation of DNA is a self-sustaining process. It is every living object's sole reason for living.
Royal Institution Christmas Lecture, 'The Ultraviolet Garden', (No. 4, 1991). Quoted in Vinoth Ramachandra, Subverting Global Myths: Theology and the Public Issues Shaping our World (2008), 187.
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In science it often happens that scientists say, 'You know that's a really good argument; my position is mistaken,' and then they would actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time something like that happened in politics or religion. (1987) -- Carl Sagan
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