Talk:Richard Dixon Oldham

Propagation of error: Molten core?

This is a neat instance of how Wikipedia insists on propagating error. An earlier version of this article had it more nearly right. Dixon argued that the Earth must have a core as S waves were not able to travel as quickly through liquids nor through the Earth's interior as through less dense matter. However, the identification of the core as molten, often attributed to Oldham, came later. It is not clear whether the equipment available to Dixon would have allowed him this stronger inference.

The article has been re-edited by a non-scientist for fun and fancy, without going back to Dixon's papers - or even back to a website that is cited.

• As I explained, I was citing secondary sources covering his works. If you are able to provide other sources which make your assertion - and by that I mean "sources up to or exceeding the strength of a peer-reviewed paper" - feel free to do so. Ironholds (talk) 04:49, 28 September 2011 (UTC)

Sadly, the problem for Ironholds is that the secondary source selected, a personal tribute by William Bragg thirty years after the event, may well, in the nature of such tributes, not have been peer-reviewed; in any case, it is not by someone directly familiar with the topic under discussion. — Preceding unsigned comment added by 133.31.18.69 (talk) 12:22, 1 October 2011 (UTC)

More amusingly yet, Bragg does not use the word `molten' in discussing Oldham's work: ``In a paper, published in 1906, analyzing the seismographic records of fourteen world-shaking earthquakes, Oldham established the existence of two distinct sets of deep-seated waves, traveling at different speeds; and, from the way in which the waves of distortion were damped out in depth, he deduced the existence of a central core in the earth, four tenths of the radius in thickness, which contrasted in physical properties with the external shells. In this way Oldham pointed to the pretty analogy between seismic waves as a source of information regarding intratelluric conditions and those of light which, on analysis by the spectroscope, give information regarding the composition of the sun's atmosphere".span style="font-size: smaller;" class="autosigned">— Preceding unsigned comment added by 133.31.18.69 (talk) 08:33, 5 October 2011 (UTC)

I'm glad you are able to access Bragg's paper, because I couldn't. RockMagnetist (talk) 18:07, 26 October 2011 (UTC)

Do Dixon's own papers count as peer reviewed?

There is a curious refusal to go back to Dixon's own papers even when most if not all are available on the website of Roger Bilham that is the cited source of the picture of Dixon used to illustrate this entry in Wikipedia. If some stigma attaches to Dixon's papers, perhaps that should be mentioned in the entry. It might be added that the picture of Dixon used is that appearing in the obituary notice of the Royal, which is among the few secondary sources cited. A further secondary source that clarifies matters relating to the Earth's core is the work of Harold Jeffreys on tides in 1926, on the basis of which Jeffreys was the first to give an estimate of the rigidity of the core, the existence of which Dixon had established without being able to tell the nature of the core, molten or otherwise. Curiously enough, Jeffreys work is not mentioned in his Wikipedia entry, although it does mention his opposition to the idea of continental drift; of relevance would be the 2nd (1929) edition of Jeffreys' book ``The Earth, Its Origin, History and Physical Constitution", the 1st (1924) edition of which is listed in the Wikipedia entry (Jeffreys is also the source of some amusing biographical comments on Dixon, again to be found at Bilham's website). We do pick up a bit more of the story of the nature of the Earth's core when we come to the entry for Inge Lehmann. — Preceding unsigned comment added by 133.31.18.69 (talk) 05:50, 1 October 2011 (UTC)

External link: the open access of Roger Bilham's website on Oldham <http://cires.colorado.edu/~bilham/Oldham.htm> — Preceding unsigned comment added by 133.31.18.69 (talk) 06:24, 1 October 2011 (UTC)

Dixon on the Loculus (Stomachion) of Archimedes: Nature, March, 1926

Again an earlier version of the entry contained some information pertinent to the Wikipedia entries on Archimedes' Palimpsest and Ostomachion: ``Oldham had wide interests and, while researching aspects of the Rhone Valley, encountered mention of the loculus of Archimedes or Stomachion. In a letter to Nature in March, 1926, he pointed out how the Stomachion board proposed by Heinrich Suter in translating an Arabic text could be reconciled with the fragment of Archimedes' Stomachion found in the Archimedes Palimpsest by subjecting it to a lateral stretch by a factor of two. The letter triggered a fad for the dissection puzzle".

So, here the question is whether a letter in Nature is an adequate source? The exact citation is: Nature, 117, 337-338 (6 March 1926) | doi:10.1038/117337a0, as can be verified by going to <http://www.nature.com/nature/journal/v117/n2940/pdf/117337a0.pdf>. Unfortunately, free-standing access costs USD32. — Preceding unsigned comment added by 133.31.18.69 (talk) 06:24, 1 October 2011 (UTC)

Please sign and date your comments

You are providing a lot of useful information. But please don't edit out the signatures provided by the bot; just added more material after the signed part. Better yet, sign and date your comments. It's easy – just add four tildes at the end (see Wikipedia:Signatures). RockMagnetist (talk) 18:07, 26 October 2011 (UTC)