Category: learning curve

Buys Ballot’s law

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I honestly thought* when I saw this that it was how Trump “won” the election, but as probably all my readers already know, Buys Ballot’s law is:

the relation of wind direction with the horizontal pressure distribution named for the Dutch meteorologist C.H.D. (Christophorus Henricus Diedericus**) Buys Ballot, who first stated it in 1857.

It’s a rudimentary method of estimating the position of varying centres of local atmospheric pressure from the prevailing wind direction.

Obvs.

Basically, it works around the relationship that (theoretically) states that the angle between the wind and the pressure gradient is a right angle. That means that in the Northern Hemisphere a person who stands facing away from the wind has high pressure on the right and low pressure on the left; in the Southern Hemisphere, the reverse is true.

We’re in the Southern Hemisphere [checks quickly… yep], so that means that if I stand with my back to the wind, then the low pressure area will be on my left (to be more accurate, it’s actually just slightly forward of my left), and the high pressure area on my right.

But why would I need to know this? Well, I probably wouldn’t, because I’m not a seafarer, miles out in the oceans. And if I did need to know it, then I’d just look at the nearest computer and it would show me where everything was. But in 1857 and for a long time before and afterwards, that wasn’t an option, because the internet was still dial up and that meant that you had to be attached to a really long cable.

Not possible in the middle of the South Atlantic (I am reliably informed).

So this law allowed sailors to estimate where the storm centre was, and thus allowed them to try to avoid it. Of course, you might not have been able to avoid the storm completely, but you could avoid the most dangerous quadrant – that is, the section of the ocean in front of you where the chances of damage from the storm was highest (Northern Hemisphere – front right, Southern Hemisphere – front left).

Less damage in those days (and maybe still even these days) meant more chance of survival.

There are a lot of factors that can mess up the wind/pressure relationship – it doesn’t work near the Equator, for example. But we’re not [checks quickly… nope] near the Equator. And though technology has far outpaced Buys-Ballot and his work, his law obviously still holds true. We just do things differently now.

Next time it’s a bit windy, cancel a marathon give it a go, then impress your friends by comparing your estimates with your modern day synoptic chart.

.

* I didn’t, this was just for comedic value.
** Crazy name, crazy guy.

Yesterday, I discovered Derek Paravicini

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I mean, discovered for me. He was already very much about, like when the Khoikhoi when Jan came to the Cape and the Indigenous Americans when Chris went across the pond.

I just found out about him for the first time yesterday.

Who is Derek Paravicini?

Derek Paravicini is one of the most extraordinary pianists and musicians of his generation, yet he is blind and has severe learning difficulties and is on the autism spectrum.
Based in London, Derek performs regularly across the UK, and is also making a name for himself internationally having performed in venues across Europe and the United States.
Derek has a repertoire of tens of thousands of pieces — all learnt very rapidly, just by listening.

Beneath his quiet charm lies a fiery, creative musician, whose astonishing improvisations and dazzling technique have wowed audiences all over the world, with many millions of views on his YouTube channel and a much-revered TED talk, that has been translated into 26 languages.

I came across him on social media on this Facebook reel, and I was “reeled” in (rofl!) primarily because I love the song in question, the beautiful Avril 14th by Aphex Twin:

Derek – as you will see below – gets played about 30 seconds of this and then just absolutely nails his version of it. Even picking up on the tiny excerpt of the gentle repeating phrase which makes up a lot of the beginning of the song, but not so much in the bit he hears.

I know – I know! – I share a lot of videos on here and tell you that it’s worth your time and effort watching through to the end. But this one just blew me away.

It’s definitely well worth your time and effort watching through to the end. Obviously.

Derek’s website is here, with all his links to social media readily available. He’s also part of the Derek Paravicini Quartet (who knew?), which you can find more about here.

About those lemurs

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Yesterday, we filled you in on how to identify your raccoons. Not that hard, given that there are only 3 species, and they are pretty much geographically distinct. Your only real issue is around Panama, which interestingly is pretty much the same as when you are traveling the length of the Americas.

Today, we’re upping our game a bit and bringing it back to Africa (and North Carolina), with a great guide on how to tell lemurs apart. The clever guys at the Duke Lemur Centre have noticed that aside from a few different personality traits and odd bald spots, their Ring-Tailed Lemurs have telltale signs regarding their ear shapes. And they’ve made a quadrant chart to assist them (and others) in how to identify their RTL stock. The four different ear shapes are Round and Elf (most specifically regarding the tufts on the lemurs’ ears), and Cat to Airplane (basically pointing upwards or sideways):

Of course, this doesn’t help distinguish Ring-Tailed Lemurs from other lemurs in the way that yesterday’s raccoon graphic does. But you can use the rings on their tails to do that. And the fact that at the DLC, they’ll be in the Ring-Tailed Lemur enclosure.

I love the personalities in the shot above. Aside from Seagrams (middle-left, just to the right of the word Round), who looks like he’s just been arrested, all of the other lemurs there look like they’ve just gone in for their passport photos, which is actually quite amusing; but I’m wondering if you could further identify at least one of them – it’s Liesl (middle-bottom) – by her amazing resting bitch face.
Wow. Someone got out of bed on the wrong side that morning.

However, when Liesl is happier and Seagrams hasn’t just had a mugshot, remember that ears are the way to go for RTL ID.

So that’s Raccoons: geographic location, and lemurs: shape of the ears.

Will this ad-hoc foreign mammal identification series continue tomorrow?
I don’t think so.

And honestly, that’s probably a good thing.

Know Your Racoons

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Almost forgot to blog this evening after a bit of a weird day.

So quickly let me educate us all on racoons:

There’s absolutely no need to know this information in Africa (unless you are heading for a pub quiz), but then you never know when you might be heading for a pub quiz, so here it is.

Tomorrow (if I remember): Know Your Lemurs.

I’m not even joking.

I’ve been using Amazon

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and…?

And I’m pretty impressed. They’ve entered into the fray in SA with a mountain to climb in terms of getting market share in online shopping delivered to your door, given that Takealot have been around for a long while here with virtually no opposition.

But Amazon have started small and sensible: a limited product range, but each one with the guarantee that it will get to you cheaply and quickly. And it works. I ordered a soundbar and paid a whole R2 (less than a penny) to get it delivered that evening. I ordered a mousemat (because my mouse doesn’t like how shiny my new desk is) and it cost nothing to get it delivered the following day.

Compare this with Takealot, whose confusing price structure for deliveries actually makes it difficult to compare, but a next day delivery would likely be R50 or R75. Or you could pick it up at one of their depots for R35.

Same day? Virtually unheard of, but almost always in three figures. (Yes, unless you have their monthly subscription service, but I’m doing apples and apples here.)

And it’s sad to say that Takealot have been lounging on their monopoly. Their prices – always allegedly discounted – only ever match with the normal prices everywhere else. I’ll certainly be using Amazon whenever possible for those online purchases. And yes, using local businesses for stuff too, but only if they are willing and able to offer decent prices and service.

You do wonder though – how quick could an Amazon delivery actually be? Like, if you needed something small, but really – really – urgently?

Mere seconds, it turns out (this service is not available in SA) (yet).

Such a good video, if you have the time to watch. Some delicious, subtle, dry humour, some incredible engineering and some amazing attention to detail and high quality workmanship.

It’s the future. Now.