Friday, 25 October 2024

Cumecs

I was interested in the board for the river flow gauge at The Hermitage near Perth. I'd never come across cumecs as a unit abbreviation. 

Thursday, 24 October 2024

Durham Geology Map

I loved this map on the pavement outside the Bill Bryson library. They have done their best to make the stones in the pavement match the correct type found in that location.
Here's Cumbria. Wigton is indeed on some lovely red sandstone - but clearly not our easy wearing type!

Wednesday, 23 October 2024

Units for pressure

This came through my door. Pressure can't possibly be measured in joules. Those are units for energy. 

Tuesday, 22 October 2024

Durham Cathedral Meridian Line

I found this notice and looked across the cloisters to see one covered over section.
And below is the view from the other side.
Their website says it is quite recent: 1820s. They made a mark at noon when the Sun was highest in the sky on summer solstice. The mark is on the floor.
Repeated at winter solstice and the lower sun puts the mark higher up the wall.
They drew a line between the two. On any other day, when the Sun hits the line it is noon. Watches and clocks can be set by this. The website says this was necessary because devices were less reliable in those days. This was still before train timetables so there wasn't a standard time across the country. This fixed local Durham Mean Time.

Which I guess means I was wrong about Murdoch Mackenzie's Meridian in Kirkwall. It probably wasn't for surveying purposes as a base line but was to fix accurate local time.

Monday, 21 October 2024

And the pressure has gone right back up again!

An impressive rise of 0.5 inHg in 12 hours. 

Sunday, 20 October 2024

Bombogenesis

With Storm Ashley raging around us, I was interested in an article that told me about bombogenesis. This article spells out the definition. My barometer works in inches, so it would be a fall of 0.71 inHg in 24 hours. I last set the reading marker a few days ago and it has come down 0.6 inHg in that time. Not bombogenesis but quite a fall. Reading the article carefully shows that it depends on latitude. I can see how but not why. We are 54 degrees North and would then need a fall of 22mb. I converted my readings and had a fall of 21mb, but I think that was over 3 days not 24 hours. It's got me paying more attention to the baromter.

Saturday, 19 October 2024

Murdoch Mackenzie's Meridian in Kirkwall

I found the line in the pavement in Kirkwall. 
I was wondering if Murdoch Mackenzie had been working on the time problem on ships. It turns out he was mapping North Ronaldsay. I thought that this must have been the base line for his map against which he made the measurements. But if you read the post on Durham Cathedral Meridian Line from 22 Oct 2024, it's most likely this is a line to fix local Kirkwall time.






Friday, 18 October 2024

Interesting scale

 

This was in the Botanic Gardens at Oxford. Apparently the Scoville Scale is based on chemical analysis. I was trying to work out whether it was logarithmic. But as it seems to be ranked against variety, which is not a linear scale, there shouldn't be a clear spacing between each level.

Wednesday, 16 October 2024

Colder inside than out

Strange conditions with a wad of warm damp air coming after the house got cold. There is condensation on the outside of the windows because the cold inside is making the glass surface temperature low enough.