John Naylor

This puts me in mind of Descartes for whom matter was absolutely rigid so light travels instantaneously from source to receiver & the impact of a stick against the ground is transmitted instantaneously to the hand that holds it. In the situation you pose I assume the pull takes .2s

Arguably, the only “proof” of “his” law provided by D was its use in his successful account of the angular diameter & shape of the rainbow. Explanation for its colours had to await Newton. Harriot had forestalled both by 1605, though he never published this work.

In a letter (1632) to J. Golius, Snel’s successor in the chair of Maths at Leiden, Descartes cheerfully admitted that he had never carried out a direct experimental test of the law. Golius found that Snel had already discovered the law of refraction, but never suggested that D. had plagiarised S.

Assume that moon is close to full phase?

I'm going to try this with a small glass sphere. Either drop sphere or raise/lower camera. On a sunny day, of course. And we've had a few of those recently in UK.

not to mention editors!

This is one of those things that one knows must be true, but hasn't bothered to see in the flesh, so to speak. Well done!

C. indirectly responsible for the term “scientist” who in 1833 asked Wm. Whewell to come up with a more inclusive term in place of “natural philosopher”. But the word did not come into general use in the English-speaking world until the 1860’s. W.W. responsible for much scientific terminology

Interesting. I had not realised that yellows & oranges are due to pigmentation. But I am sure that that blues are due to interference, not refraction.

I learned about this during a talk about the Jubilee Line (London's most recent tube) some 15yrs ago. The lecturer, a civil engineer who had worked on the project, said that in search of best concrete they analysed the mortar in a roman fort on the South coast (had lasted ~2000 yrs)

Runge & Goethe corresponded on the subject of coloured shadows, a phenomenon first described by da Vinci tinyurl.com/25b49db9 & correctly explained by G. Monge (1789). Descriptions on how to produce such shadows by Goethe tinyurl.com/476pbny6 & Rumford tinyurl.com/43w5vzj9. My flashlight version

A timely reminder that to see a rainbow one must turn one's back on the sun.

And made the mistake of opening at random Augustin's Confessions on reaching the summit of Mt Ventroux and reading his admonishment that men should not admire the natural world rather than the human soul. Deflated, he descended in silence.

You could use an lcd panel (set to white) as a source of polarised light.

As the author of "Now Hear This, A Book about Sound" I shall be listening on #WorldListeningDay to Radio Lento if I can't get out and about. ebook available at a generous discount here tinyurl.com/bdcud8mv

Here is its audio spectrum

As an aficionado of sources of unusual sounds, I commend your wife’s ambition! My shop bought TT produces a large number of closely spaced harmonics, which one would not guess from its raucous sound. My T.T., 18cm long, is loudest at ~450Hz.

Pleased to see a review of Bohren's "Clouds in a glass of beer" A later work: "What light though yonder window breaks". Pity that such books are no longer published. An acquaintance of mine was taught by Bohren and said that he did not suffer fools, as is evident in both these books.

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From the expressions on these faces I can tell that people in the 16c experienced the same emotions as we do today. But I & they would certainly struggle to understand our respective world views.

I love images of shadows but I can’t work out where the photographer was standing

I spy a couple of inferior mirages (2 & 3)

Acoustic dispersion occurs in many situations. Known as acoustic whistlers, I have heard this phenomenon as a train draws up to a station and when a stone is cast onto a sheet of lake ice. Of course this is a temporal effect, not spacial.

no gin?

Now you mention it…

The moon is the only source of reflected light in this image

The remark was made to Hooke and given their frequent ill-tempered disagreements, the compliment may not have been entirely sincere; it was nonetheless true. Newton had learned a great deal about light & gravity from Hooke.

Had it not been for E. Halley, Principia would never have been written. Not only did H. rekindle N’s interest in the matter of gravity etc, H also had convince N of the importance of finishing the work & oversaw & paid for its publication. H should be considered the midwife of Newtonian physics!

T. v. attentive to sounds “At the entrance to the Deep Cut, I heard the telegraph wire vibrating like the Aeolian harp”…“The telegraph harp sounds strongly to-day, in the midst of the rain. I put my ears to the trees and I hear it working terribly within… the sound seems to proceed from the wood.”

This is a roll cloud, not K-H.