User talk:RolandJacksonUK

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Welcome to Wikipedia, RolandJacksonUK! Thank you for your contributions. I am MartinPoulter and I have been editing Wikipedia for some time, so if you have any questions, feel free to leave me a message on my talk page. You can also check out Questions or type at the bottom of this page. Here are some pages that you might find helpful: Also, when you post on talk pages you should sign your name using four tildes ( ~ ); that will automatically produce your username and the date. I hope you enjoy editing here and being a Wikipedian! MartinPoulter (talk) 13:22, 31 January 2020 (UTC)
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Tyndall on colour blindness

 * Hi Roland, think you've already noted that, "as John Perlin has found, a paper of [Tyndall's] on colour blindness was reprinted in the 1856 journal in which Foote's paper appeared, not necessarily with his knowledge." Don't know if you've updated that more recently. Time magazine reported "Did Tyndall know about Foote’s paper? It’s unclear — though he did have a paper on color blindness in the same 1856 journal as hers." They link to to her paper on pages 382–383 of the journal. It also shows the index of issue Number LXIV on p. iv, which under Miscellaneous Intelligence gives p. 142 for Tyndall's paper. Unfortunately it doesn't include that page, but p. vi shows Foote's paper was in issue Number LXVI – although they were republished in the same bound volume, not the same issue of the journal. As my edit notes, Tyndall's paper had already appeared in the May 1856 issue of The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science. regards, . . . dave souza, talk 21:51, 8 March 2020 (UTC)


 * Also, in your edit comment you said you didn't "think long-wave infrared had already been identified by others at that point as the basis for the greenhouse effect." Fourier is commonly credited with the "greenhouse" concept, as one translation puts it, that the temperature of the Earth can be augmented by the interposition of the atmosphere, "because heat in the state of light finds less resistance in penetrating the air, than in repassing into the air when converted into non-luminous heat." Herschel had by then published his research into what we call infrared, and before him de Saussure had experimented "to show the existence of infra-red radiation, which he calls obscure heat", according to the translator. In a note on p. 6, de Saussure gives credit to earlier research using a burning mirror: "One reads in the Mémoires de l'Acad. Des Sciences for the year 1682 of a similar experiment by M. Mariotte. 'The heat of a fire reflected by a burning mirror is sensed at its focus; but if one puts a glass between the mirror and its focus, the heat is no longer sensed'." Tyndall (1859) refers to the observations and speculations of de Saussure, Fourier, and others, "on the transmission of solar and terrestrial heat through the Earth's atmosphere", which also refers to longwave infrared. To keep articles concise and clear to modern readers I think it's fair to use current terminology, though in more detailed articles it's worthwhile noting the terms used in the past. . . dave souza, talk 22:39, 8 March 2020 (UTC)

Hi Dave I don't really have a clue how to use talk pages, and the instructions are not helping me, so I'll just try like this. I can't otherwise see how to respond.

On your first point (colour blindness) I'm not sure what significance you are giving to this. We have no evidence that Tyndall knew his paper was republished in that 1856 journal. He wouldn't have submitted it there. The concept of copyright didn't really exist then; there was no copyright agreement between Britain and the US.

On the second point, I was probably being a bit too wary of using modern terminology with reference to the past, though it can leave people over-claiming what someone actually did and understood at an earlier time, before the relevant word/concept was invented, so it needs treating with care. Indeed, Fourier and others had described (part of) what we now call the greenhouse effect in terms of the absorption by the atmosphere of 'non-luminous' or 'obscure' heat, which we would now class in the infra-red. It should be noted, as far as I'm aware, that they did not recognise the existence or significance of the subsequent radiation of heat by gases in the atmosphere (including what we'd now refer to as down-welling IR), nor did they show any of it experimentally. Tyndall described the whole process of absorption and radiation in, I think, the first 'modern' description of what we now call the greenhouse effect. Equally, he experimentally demonstrated the absorption of heat by individual gases, showed good absorbers were good radiators too, and identified which gases were and weren't responsible. The best paper I'm aware of on the subtleties of this is Joshua Howe's chapter 'Getting Past the Greenhouse; John Tyndall and the Nineteenth Century History of Climate Change'. RolandJacksonUK (talk) 14:20, 9 March 2020 (UTC) 14:42, 9 March 2020 (UTC)RolandJacksonUK (talk)
 * Many thanks, Roland, that's exactly the right way to use talk pages! (both article and user talk). A refinement is using colons at the start of a paragraph to indent successive comments, as I've done here.
 * On the first point, agree with what you're saying, my concern is that Perlin's advocacy as reported in sources gives readers the impression that Tyndall "does not mention her in his paper, even though he published a report on color blindness in the same 1856 AJS in which Foote's work was published." I'm only an amateur, but from what I can see it wasn't the same issue of the AJS, and "even though" is innuendo with no factual basis. It maybe makes sense to remove the sentence about the colour blindness paper, and copy it to the article talk page for any discussion there, but thought it would explain why we don't mention the implied claim that he must have seen her paper. Reply here if you think we should just leave it out. . . dave souza, talk 15:49, 9 March 2020 (UTC)

Thanks Dave. I'd take that sentence out as it can only really be interpreted as an innuendo (otherwise why is it there?). But I leave it to you or someone else independent to do that. It's probably well known that I disagree with John Perlin on his interpretation of some of the evidence (or lack of it).RolandJacksonUK (talk) 17:00, 9 March 2020 (UTC)
 * Thanks Roland, have removed it and put it on the talk page in case anyone wants to reexamine the point. . . dave souza, talk 11:52, 10 March 2020 (UTC)
 * On the second point, agree that understanding of the "greenhouse effect" went in stages, and wording shouldn't suggest early researchers had the full modern picture including down-welling IR. By coincidence, I've noticed that the Eunice Newton Foote section cites a source quoting Perlin as saying "That is uniquely proficient at absorbing and radiating solar heat back to earth was discovered more than a century and a half ago — by a woman." If I've got it right, Perlin doesn't understand the infrared component that Fourier suggested, and Tyndall measured. Think we can do better, apparently Perlin is "writing a book about Foote to make evident Foote's primacy in laying the foundation for understanding the greenhouse effect" so we'll just need to find good verification from published sources to put that in context. There's also this article, apparently "passages of Tyndall’s article, Perlin charged, were lifted verbatim from Foote’s paper". Seems improbable, haven't bothered with trying to guess what that's about. . . dave souza, talk 16:51, 9 March 2020 (UTC)
 * In a related point I thought might interest you, Happy 200th birthday ... NOAA shows carboniferous geology, and Foote's "remarkable insight about carbon dioxide and Earth’s past climate" that "if as some suppose, at one period of its history the air had mixed with it a larger proportion than at present, an increased temperature... must have necessarily resulted". The implication being global cooling to the present rather than warming. Rudwick's Worlds Before Adam shows the geological context including Laplace and Fourier, and Brongniart proposing that huge fossil plants suggested hypertropical climate, while the amount of carbon in "coal itself implied that the atmosphere might have been much richer in carbonic acid (e.g. carbon dioxide) than it now is: perhaps up to 8%, he suggested, in place of the present 0.1%."p. 171 Think this is likely to be what Foote was thinking of, but am cautious about adding synthesis to the article without a source making the connection. . . dave souza, talk 16:51, 9 March 2020 (UTC)

On your second point again, I'm not sure anyone's really got to the bottom of exactly what Foote discovered, or how she thought about it. The fact that she doesn't reference anyone makes it very difficult, and her husband's paper (which precedes hers in the journal) is not easy to make sense of either, but must link to hers conceptually I suspect. How were they actually thinking? You may well be right in your suggestion, but we don't currently know what she had read so I think you're right to be cautious. One problem is that I doubt she detected direct absorption of IR from the solar spectrum by her gases. Even if the (presumably glass) container was transparent to IR, most/all of it would anyway have been absorbed by 8km of atmosphere, including CO2 and H2O, above her apparatus before it got there. So I assume she was in fact detecting absorption of heat radiated from her apparatus or the surroundings (heated up by the part of the solar radiation that did arrive). Her experiments 'in the shade' (whatever that means) are presumably relevant here, but she never attempts to interpret them. Did her glass apparatus have stoppers? Made of what? Cork? Metal? Metal painted black? Did they absorb heat? We don't know. I don't understand how anyone could claim that Foote discovered that CO2 "is uniquely proficient at absorbing and radiating solar heat back to earth". What is meant by "solar heat" here? (or indeed "uniquely proficient"?). How does her experiment show that CO2 "is uniquely proficient at absorbing and radiating solar heat back to earth"? It does nothing of the sort. It doesn't show that CO2 absorbs solar heat directly, as far as I can see, and it doesn't show that it radiates heat. And in any case, the greenhouse effect is not caused by the direct absorption of solar heat. It's caused by the absorption of heat radiated from the earth's surface (followed by further radiation by the gases that have absorbed this heat). We do need to give Foote due credit, as she seems to be the first person to posit the link between CO2 and climate based on experimental evidence, making a perfectly reasonable supposition, even if the experiment is difficult to interpret (and even an eminent physicist with whom I have communicated on this finds it problematic to explain the physics of the actual heating of the gas in the apparatus). But over-claiming does no-one any good. Nowhere in her paper does Foote explain, describe or reference anything resembling the greenhouse effect as we currently understand it (and as Tyndall clearly spelt out). That doesn't mean she wasn't aware of it, but we have no current evidence that she was, that I know of. Incidentally, as for Tyndall lifting stuff from Foote's paper, I can see no sign of that, but since I'm not aware that Perlin has published his evidence for that claim I can't really comment further. RolandJacksonUK (talk) 17:57, 9 March 2020 (UTC)
 * Thanks Roland, these are good points. The Scientific American article does say they were glass cylinders, so that may have been part of the verbal report but it's not in Foote's paper. The Regognition section had a misleading statement about current controversy cited to your paper, so I've tried to replace that with a more accurate summary. Please feel free to edit it, or comment here if changes are needed. If Perlin's claims get more attention, we can look for sources for a suitable response. Thanks, . dave souza, talk 12:28, 10 March 2020 (UTC)
 * Many thanks Dave. That looks very measured to me. RolandJacksonUK (talk) 12:48, 10 March 2020 (UTC)
 * Thanks, Roland. Just to let you know, I've added two introductory paragraphs to John Tyndall (permanent link) to show the timing of this aspect of his work, and the sequence following on after he'd begun work on glaciers (though that work then overlapped). That's me done with the topic for now, will watch out to see if there are more developments on the Foote issues, . . dave souza, talk 12:05, 13 March 2020 (UTC)
 * Thanks Dave. Looks good. One day I'll take a look at the Tyndall wikipedia entry in detail, but having just published an extensive actual biography I've had enough of biography for a while!