Mapping the Meridians - Objectivity 97 

well, the correct use of a strikethrough is not to conceal information, but to communicate that's to be culled from the next draft/version

but im interested in also what he thought it was based on his measurements

From what I just read, and it was confusing as all hell, seems he laid out the total distance to be about 160,650 fathoms (+- depending on which spheroid you use). Units weren't exactly all that standardized back then, apparently a fathom could range between 5 and 7 feet. If you use the upper end you get 213 miles.

213 at the upper bound and he probably wasnt the exact what he used thats pretty close

If you stop at 6:27 you'll see that is just shy of 2°40' as an angle.

~337.9km from the longitude at 6:27 and using 51.509865 for London lat. and 48.864716 for Paris lat.

+hesgrant thanks for watching us. Tell your friends. ;)

+Objectivity I do, and I will continue to, you guys are great :)

I thought of you folks before he even said the number aloud. Yay, FIRST!

Seems like you missed the 2 unnumbered videos then.

Ameto Lmao, I was just going by the video number on the title. I've been here since the start.

Brady?

That would be Brady.

I believe that's Brady.

Bradypus

Add three more.: Circumference: Eratosthenes and the Ancient Quest to Measure the Globe, The Measure of All Things: The Seven-Year Odyssey and Hidden Error That Transformed the World and Measure of the Earth: The Enlightenment Expedition That Reshaped Our World

Which will be based on the map projections used by Google. Unfortunately, this is a rather complex matter.

That's not the same as the distance between the meridians through the two cities.

MichaelKingsfordGray a straight line following the curve of the earth

...stay tuned! :)

The Greenwich Meridian uses local vertical as defined by gravity, which does not quite cross the centre of the Earth. The GPS prime meridian, on the other hand, does not include local gravity in its model of what it considers vertical at each point, so even though the two have seemingly identical definitions, the slight deflection of a plumb line in Greenwich means that the two are about 102 m apart.

ashley beaumont I think he talked about this on an episode of Hello Internet. You're actually at a greater risk of damaging a book with gloves than without, IIRC.

ashley beaumont had the same question myself

you lose a tiny bit of control as you cant feel as small a detail and it causes more human error when say turning a page you pull a tad to hard kinda thing

I've seen a lot of people asking this question on this channel, and whenever I see it I wonder if those people ever tried to flip book pages while wearing gloves.

ashley beaumont They explain that on Hello Internet, Brady and Grey's fantastic podcast. Specifically Episode #40: Oval Office of Science, you should really check it out! :D

The answer to the distance between London and Paris, perhaps?

In surveying, angles more precise than the instrument can measure directly are measured through a process of repeated measurements. The scales are constructed so that the halves can be locked together and rotated with the telescope, or one half can be fixed to the body of the instrument while the other rotates with the telescope. If any clockwise rotation is done with the scales unlocked, and any counter-clockwise rotation with the scales locked, the instrument will begin to read the cumulative angle of multiple successive measurements of the same angle. The same angle is measured a number is times to an accuracy of minutes, then the cumulative angle is read off the instrument and divided by the number of measurements. Often the scope in the instrument is flipped 180° on a horizontal axis between repetitions to cancel out any errors in the construction of the instrument.

@@beefchicken I see. So by a aggregating results from repeated observation, they can improve the resolution. Even so, the implied precision seems implausible. Were they keeping an extra digit or two for the purpose of minimizing error propagation or something? Even modern digital theodolites can rarely measure to a tenth of a second.

They are called surveyors. I personally, love metrology. From old brass sextants and theodolites to modern laser interferometers and the ultimate measuring device, the Watt Balance (aka Kibble Balance), at the US National Institute of Standards and Technology, that is being used to define the standard Kilogram based on Planck's constant.