John Naylor

I couldn't place the photo, was it the visit to the euro tunnel project?

Flattered by your description of me. I retired in 2004, so my recollection of past pupils is hazy at best so I can't quite place you, though I remember the astronomy O level. Images you posted of a telescope & eyepieces imply a continued interest in the sky.

In my view Jonathan Treitel gets closest to the correct explanation. It would appear that an interest in colour naming is comparatively recent.

Whenever I see Jupiter close to the moon it makes me realise that I am seeing something incredibly large at a huge distance next to a body that is relatively very small (40x smaller than Jup) that is over 100x closer to me.

Les Cowley's www.atoptics.org.uk a far better source of info on atmospheric optics. Now, sadly, no longer actively maintained

Died OTD, French physicist, Felix Billet, published in 1868 results of an experiment in which he illuminated a thin, vertical stream of water with sunlight and managed to see 19 rainbow orders including supernumeraries. He named it “la rose des arc-en-ciel”, known in English as Billet’s Rose.

You may be interested in Wollaston's diagram of how he observed the absorption lines. Not by projection, but by looking at the slit through a prism. His paper on the subject was published in Phil Trans 92, p365: "A Method of examining refractive and dispersive by prismatic Reflection"

Wm Wollaston (1802) was the first person to employ a very narrow slit to create a spectrum of sunlight & observe absorption lines. Newton couldn't achieve a well separated spectrum because his "slit" was “a round Hole, about one third Part of an Inch Broad, made in the Shut of a Window"

Poe was the first person to come up with a plausible solution to Olbers’ Paradox (i.e. why the night sky is dark). In lecture, later published under the title EUREKA, he suggested that the reason why the sky isn’t ablaze with light is that light from the most distant stars hasn’t yet reached us.

John Ruskin, Modern Painters Vol 1, Section V. Ch1. p. 496 ‘The truth of water’

Puddles enliven a walk, as Ruskin knew well!

Luke Jerram Museum of the Moon

Braille Moon Map provided for visitors to Museum of the Moon exhibition

I went the the Natural History Museum (London) In June 2019 to see Luke Jerram's splendid Museum of the Moon. Although the surface of the sphere was smooth, the shading fooled one's eye into interpreting it as embossed. My tactile acuity with Braille map didn't my match visual acuity!

Having found that I have been baking to the higher temp, & much preferring the result without knowing why, I am like Moliére's M. Jourdain: "By my faith! For more than forty years I have been speaking prose without knowing anything about it, and I am much obliged to you for having taught me that."!

Guide by the advice in this blog I baked bread in my usual way and found that I end up with a loaf just short of 100°C. I then baked one that came out at ~88C. But unlike the author, I far prefer the former texture. I found the cooler loaf too squashy. Thanks for the reference!

I devoted several pages to this issue in my book on the rainbow because I was surprised that its colours are never mentioned in any of the pre-scientific myths about the phenomenon. Gladstone, as you may know, concluded that ancient Greeks must have been unable to perceive colour.

Cultural considerations are as important in the perception of colour as physiology. Experience suggests that colour perception is automatic and that no special effort is necessary to see colours, so the widespread indifference to colour in pre-scientific languages (e.g. Homer) is surprising.

And a body to experience those emotions.

Thanks. This is really interesting. Just have to convert °F to °C.

You know, it had not occurred to me to use a thermometer when I bake bread. I use sound, i.e. tap the base. But I will use a thermometer next time out of curiosity.

Moire patterns are often noticed as one's view of the elements that create them changes. Here is a short film of a moire formed by Venetian blinds and a garden fence with open horizontal slats.

I usually rely on a thermometer when cooking. The days of uncooked baked potatoes & joints of meat are history!

I saw the same thing many years ago as I travelled by train across SW London. The foot of the bow appeared to leap from one building to the next. This was long before the days of smart phones, so the only record is a memory!

The variation of pressure with altitude was confirmed by B. Pascal in 1648 when he persuaded his brother-in-law, Florin Périer, to take a barometer to the summit of Puy-de-Dome, an extinct volcano near the French city of Clermont-Ferrand.

You are quite right. As an enthusiastic home cook I often stop to consider the science of what I am doing: eg thermal properties of foods & the container/medium/heat source in which they are cooked.

If ever you need proof that a rainbow is centred on the ye of the beholder…

What I meant by “knowing what to look for “ also includes “on the look out for xxx when conditions seem favorable”

I have long been an admirer of Franco Fontana's abstract landscapes, and in my opinion you are his equal!

Very compelling illusion! As an alternative to a ruler, I always look at these illusions from the side. What makes visual illusions interesting is the insight they provide into the inner workings of our visual system. Am I right that there seem to be far fewer auditory illusions than visual ones?

Same here. I wonder if noticing these patterns depends on knowing what to look for, because they are often rather subtle. I am inspired to send you a sieve/shadow moire. Sieve resting on sheet of paper & illuminated from above.
May 2026 be a year in which we come across unusual ones

Turneresque

Now that takes me back! Rogers’ “Physics for the Inquiring Mind” which I found such a useful book when I started my teaching career.