Must share (Purification of Water)

@Grandpakimo
The guy actually used bottles to make a device for extracting pure water #shorts
https://www.youtube.com/shorts/MskWjuCA-3k

If You Get Sea Water

Desalinate it.

Or dilute it.

Desalination is done by evaporating sea water and collecting the vapours as they condense on some surface, for instance a transparent plastic sheet, if you do it under sun light, or a pan if you boil the sea water in a kettle.

Totally salt free water is not too goof either, distilled water can be improved in taste by adding a very small quantity of sea water to it./HGL

A Spread Like Butter, that's Not Margarine?

A) You can buy Bregott.
B) You can make something similar.

Here is how.

• 400 g of butter
• 100 g of a vegetable oil
• salt, if needed

If the vegetable oil is rapeseed oil, I do reccomend adding salt.

Heat the butter gently until liquid, mix with oil (and salt), allow to cool./HGL

What's in a Good Restaurant Sandwich? Why Are they Complicated?

Some people would not from their homes be used to putting lettuce on the sandwich, between the butter and the topping.

But the lettuce has its use. It's not just to be fancy or complicated.

A solid fact : bread is usually porose, lettuce has a hard surface.

Yesterday, I made double sandwiches from Harry's bread, a French brand of sandwich bread. As a topping, I used cucumber salad and goat cheese. For the goat cheese, no problem. But for the cucumber salad, I was partly thankful I had a second bread on top, and partly regretting I had no lettuce below. My fingers got moist.

So, to serve the same recipe in a restaurant, one would:

• put a lettuce leaf below the cucumber salad so it doesn't ooze through the bread
• put spread butter below the leaf, so it stays in place.

If you think the butter is too hard, there are two ways around that:

• dip the knife in boiling water a few seconds before putting it to the butter
• or use Bregott or a similar mixture.*

Even if the topping is not liquid, it can be smeary, like some French goose liver** pâté, and on that occasion, I was happy to have, instead of bread above it, leaves of lettuce above it./HGL

* A Spread Like Butter, that's Not Margarine?

** In fact, it was something even stickier, if you don't have lettuce or bread on the top - mousse de canard.

"Kir léger"

En parties égales, ou à peu près ...

• eau cassis
• Cinsault rosé

À servir frais./HGL

PS, si vous avez un meilleur nom pour ceci que "Kir léger" n'hésitez pas de commenter!/HGL

Salade d'un sdf

Les haricots verts, c'est un peu sec, une fois qu'on a égoutté ... huile, beurre fondue, quelque chose serait bienvenu, non?

Les sardines, c'est assez fort en goût ... même avec du pain, c'est juste un peu trop, non?

Ah, mélanger ... les sardines, il y a de l'huile avec. Et les haricots verts, le goût est suffisamment fort pour rivaliser avec les sardines, mais pas du tout âpre (une fois qu'on a de l'huile).

Mais, le problème est, en quoi mélanger?

Bon - j'avais le petit bol en carton que j'avais eu pour un dessert de Hong Kong, à emporter, j'avais lavé les deux bols pour une éventualité comme ça, et il m'en reste un.

Être sans abri ne veut pas dire être sans goût!/HGL

PS - oui, c'était une salade composée très acceptable, sinon je ne serais pas en train de la partager (en recette) ici, non?/HGL

How to Tunnel Through a Mountain with Pre-Modern Equipment

Hannah Fry (a longstanding team member on Numberphile) had a lovely exposé about how the ends of the tunnel meet up:

Tunnelling through a Mountain - Numberphile
23rd Jan. 2022 | Numberphile
https://www.youtube.com/watch?v=kwrDX5qkwvA

She left however somewhat vague (though she offered suggestions) how they knew where E and S were, and that the elevations were equal on both sides, here I step in:

1) E, W and S, N:

5:54 Compasses - drawing tool, yes.
Magnetic tool for finding N, S, anything at right angles (E, W) and anything in between, no.

Marco Polo brought these latter ones from China. In his day magnetite was explained as:

• element earth
• under influence of Mars to make it iron
• and then under influence of Venus to make it attract.

Magnets worked even so, and as said, it was in China they were first used for compasses. In early modern times they were equipped with a paper that marked off not just quarters, not just eighth parts (NE, SW etc), not just sixteenths (NNE, ENE etc) but even thirtyseconds (E by N, ENE by N)* ... Belloc wrote an essay about a sailor who went mad as his captain or boatswain was explaining this.

Now - what did Polycrates (po-LEE-kru-TEES) use, as he lived before Marco Polo?

You might use the other type of compass or simply strings and pegs, in drawing straight angles, and that would include straight angles between a shadow marked at sunset and one marked at sunrise. At equinox these would be due W and E of what was throwing the shadow, and either way they would make a line due W-E, so that a straight angle would mark the exact time when the sun was in zenit, the shadow straight N.

Ensuing exchange:

Mark Tillotson

But the magnetic properties of iron were known the Greeks, its not a big stretch for them to have the compass - after all we get the word magnet from the greek region of Magnesia, so they had magnetic rocks and iron. Thales of Miletus described magnetic phenomenon (we only have second hand accounts of this apparently) - a lot of knowledge may have been lost to the ravages of time.

Hans-Georg Lundahl

@Mark Tillotson We have no direct reason to believe Greeks used magnets for compasses.

We have no reason to believe seafarers would have lost such knowledge if they had had it.

We have every reason to believe that Marco Polo got the magnetic compass from China. And that prior to him, it was unknown in the Mediterranean.

Greeks were not all that famous for practicality in using scientific discoveries. Nero used a lens as a magnifying glass, but corrective eye-glasses only came with the Middle Ages. Archimedes used a screw for elevating water slowly - around 1400, Europe had a practical push and lift pump and was attaching objects to each other with screws turned by screwdrivers. While screws for oil presses / wine presses already existed in antiquity, Europe added screws for woodcut pressing and printing with moveable types in the Middle Ages.

2) Elevation:

6:57 Build a momentary dam around the whole mountain or at least on one side the entrances need to have contiguity around the mountain.

Then fill that dam with water. Tada, entrance levels are equally high!

* Correction on these

"(in first quadrant) north by east (NbE), northeast by north (NEbN), northeast by east (NEbE), and east by north (EbN)"

Thank you, wiki:
https://en.wikipedia.org/wiki/Points_of_the_compass