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- 1 Untitled
- 2 Images and  tags
- 3 Contradiction: Who discovered that pendula aren't isochronous?
- 4 Contradiction: Who discovered the 31 equal temperament?
- 5 Centrifugal force
- 6 Did Huygens write science fiction?
- 7 René Descartes "minor physicis" addition
- 8 Extraterrestrial Life
- 9 Not published discoveries in Protozoology
- 10 Image KettingHyugens.jpg
In case anyone else was wondering, here is a page and audio clip describing how to pronounce Huygens' name.
- He discovered and proved mathematically that the oscillation-time (or frequency) of a pendulum depends solely on its length, independent of the angle of swing. The popular notion up to then had held that the larger the swing, the longer the oscillation-time.
It is Galileo that is credited with finding that pendula have (almost) constant period; Huygens quantised the tiny dependency on amplitude and suggested a means of correcting it. (I believe it was a buffered ribbon suspension, but check his book to be sure. For the typical idealisation the bob must trace a cycloid -- see tautochrone -- and the buffers are the evolute, another cycloid.) It's of mostly theoretical interest because serious pendulum clocks are contrived to keep a small and constant amplitude, and real pendula are hardly the easily-analysed ideal; their bobs rotate, their suspensions are stiff and stretchy...
Huygens' most lasting contribution to horology may be a pulley arrangement used to maintain torque during winding. Kwantus 19:35, 2005 Feb 20 (UTC)
- D'oh. I forgot the coilspring-and-balancewheel oscillator. Kwantus 22:52, 2005 Feb 22 (UTC)
I've replaced the color portrait with one that is known to be public domain. The old one was way better, though. If anyone can find out the relevant legal information (and maybe locate a better reproduction), it would be great to have the color one.--Bcrowell 03:46, 21 May 2005 (UTC)
Is the lack of a link to Huygens' principle deliberate?
It seems the images inserted just after the LIFE section name cause the  tags to be placed bunched up in odd places. At least, when I take out the images the  tags appear in the proper place. I have no idea what is going on. Perhaps someone who has run into this problem before can fix it. Vantelimus (talk) 05:21, 18 November 2009 (UTC)
Contradiction: Who discovered that pendula aren't isochronous?
According to this article
In 1673 he [Huygens] published his mathematical analysis of pendulums... It had been discovered that pendulums are not isochronous for swings; that is, their period depends on the width of swing.
However, according to Marin Mersenne
He [Mersenne] also performed extensive experiments to determine the acceleration of falling objects by comparing them with the swing of pendulums, reported in his Cogitata Physico-Mathematica in 1644. He was the first to measure the length of the seconds pendulum, that is a pendulum whose swing takes one second, and the first to observe that a pendulum's swings are not isochronous as Galileo thought, but that large swings take longer than small swings.
The dates suggest that Mersenne was first.
- Mersenne was first to observe that pendulums are not isochronous. Huygens is notable for proving it mathematically. Added supporting citations to article, and removed "contradiction" tag at top. --ChetvornoTALK 15:22, 7 October 2010 (UTC)
Contradiction: Who discovered the 31 equal temperament?
According to this article
He [Huygens] also invented numerous other devices, including a 31 tone to the octave keyboard instrument which made use of his discovery of 31 equal temperament.
According to 31 equal temperament
Nicola Vicentino produced a 31-step keyboard instrument, the Archicembalo, in 1555, but it was not until 1666 that Lemme Rossi first proposed an equal temperament of this order. Shortly thereafter, having discovered it independently, famed scientist Christiaan Huygens wrote about it also.
According to Lemme Rossi
Lemme Rossi... was the first to publish a discussion of 31 equal temperament, the division of the octave into 31 equal parts, in his Sistema musico, ouero Musica speculativa doue SI spiegano i più celebri sistemi di tutti i tre generi of 1666. This slightly predates the publication of the same idea by the eminent scientist Christiaan Huyghens.
My guess is that the later two articles are more accurate than this one, but none of the 3 cite a source on this
- We ought to have a source, but I see no contradiction between these articles, unlike what's noted in the hatnote at Christiaan Huygens. Rossi and Huygens both discovered, independently, the 31-EDO, and apparently Vicentino preceded both with this discovery. Rossi just was the first to publish it.
- However, this page from the Huygens–Fokker Foundation states that Huygens "knew of the existence of Vicentino's archicembalo", so it would seem to be doubtful whether Huygens' contribution should be called a discovery at all. --Lambiam 18:46, 15 April 2011 (UTC)
Shouldn't the name of the force discovered by Huygens be the Centrifugal force, rather than the Centripetal force, since he called it a vis centrifuga, and it dealt with the expansion of the rotation radius.WFPM (talk) 19:56, 27 February 2011 (UTC)
Did Huygens write science fiction?
The intro describes Huygens as (among other things) a writer of science fiction, but I don't see anything in the article that substantiates this. He did write a book presenting "conjectures" (his word) about inhabitants of other planets, but that book is not science fiction, any more than the WP page Extraterrestrial life is a work of science fiction. Perhaps he did other books which are science fiction, but for now I'm inclined to delete that statement from the intro. Kalidasa 777 (talk) 23:30, 2 May 2011 (UTC)
René Descartes "minor physicis" addition
What the book cited says is that, probably due to the weight of René Descartes's other accomplishments, there was a school of research based on his physics. He and his followers contributed, to some extent, directly to physics. Partly from other sources, René Descartes' main contributions to physics were in mathematics and in the supporting and guiding philosophy, rather than in physics itself. He said cogito ergo sum, which has been generalized to the anthropic principle that a a scientist may assume that the universe is such that it supports intelligent life. He advanced the idea of searching for simple laws of physics. David R. Ingham (talk) 04:26, 26 April 2012 (UTC)
This section seems to be poorly written and I have great reservations about the wording of this section, especially the last few line which are unreferenced. The referenced section cites a book by a Margaret Jacob. I looked for a google books preview to see what was actually presented but a preview was not available. The wording in the section is shoddy and seems to be a point-of-view edit with a severe lack of quotes for supposed lines of reasoning of Huygen; either he explicitly wrote what has been said in the section, or it didn't happen and is conjecture. There is nothing specifically in quotation marks, and it seems presumptuous to state those sentences as if it were Huygens line of reasoning.
Not published discoveries in Protozoology
Clifford Dobell in the book "Little animals" (1932) writes: "Christiaan Huygens never himself published any serious contributions to protozoology: and the records of his own observations, which were made in an attempt to repeat Leeuwenhoek's experiments, remained in manuscript and unknown until only a few years ago. Consequently, his private work had no influence whatsoever upon the progress of protozoology. Had it been published in his lifetime, it would have assured him a place in the very forefront of the founders of the science".
George F. Simmons in his book "Calculus Gems: Brief Lives and Memorable Mathematics" writes: "Among other things, he explained how microorganisms develop in water previously sterilized by boiling. He suggested that these creatures are small enough to float through the air and reproduce when they fall into the water, a speculation that was proved correct by Louis Paster two centuries later".
Maybe it's worth a mention? (since people mention Gauss discovery of the possibility of non-Euclidean geometries, even though it was also not published)
Or maybe it's not relevant?
The article says cycloid, but it seems like a catenary (it's also the description in commons and seems to match the descriptions in John Bukowski's article "Christiaan Huygens and the Problem of the Hanging Chain").