I've always found contour lines a very elegant and practical solution, but never really gave a thought to the invention. After seeing one map with them, I almost immediately made an imaginary one. They've made me love geographic maps more than any maps without them. I was hooked for life. To thank you, I'll make a donation for that trip.
These are the little-known mountains of Berkshire - 'The Himalayas of the Home Counties'. Very few visitors have explored them, because they are usually concealed by a low hedge. But the actual Schiehallion is wonderful, because it can be climbed without ropes or crampons or any technical skills - you just keep walking and clambering until you reach the top. Hard work, but well worth the effort.
I'm one of those geeks who likes my fiction silly. (Hitchiker's Guide to the Galaxy is a good example.) Seeing the phrase "concealed by a low hedge" appied to something called "the Himalayas" has made my day!
It’s so difficult to decide which is the more entertaining. The information you convey, or the ‘Paul and Rebecca double act’. Whichever, your videos are always worth a look.
Well, I remember learning all about contour lines a long time ago, a very long time ago, but no one taught me the history until today. Thank you Paul and Rebecca!
When I was at school / college I hated history, not just the content but the delivery that was so dry. Since I have been watching all your vlogs I appreciate the subject so much more. In addition having done numerous outdoor courses etc I now the background of contours. So thank you
Fascinating vid you two. Contour lines were vital to canal and railway building to avoid major civil engineering works. There we are, back to canals again.
As a mountain biker, and map nerd, I spend a lot of time looking at contour lines for places to ride my bike. This is a really intersting bit of knowledge that I probably would of never heard of, thank you.
He came close to inventing the staple gun. He invented the cat flap. There is a similarity. If the thing that is supposed to go through them gets stuck, there's a nasty sharp thing to dislodge (with difficulty) before it can be used again...
@@chrisstephens6673Oh, dear…are we feeling threatened by historical realities? Seems so, as nobody is making up history to favor those groups you surely selected at random and without any underlying bigotry.
@@chrisstephens6673To be fair, most of the history we learned in school was heavily biased by colonial thinking, racism and sexism, and empire building mentalities, so it's good to learn the bigger picture about the women and coloured people who worked behind the scenes and previously received no credit or recognition for their work. 🙏
Modern gravity meters are portable, and relatively robust bits of kit (airborne surveys are also done). The principle involves measuring acceleration, and the common unit is the "gal" (after Galileo), 1 of which which is equivalent to 1 centimetre per second squared. Variations around the place, (including in Berkshire, I'm sure!) are measured in milligal, and occasionally, microgal.
And hence the reason why precision drift-less inertial positioning / navigation won't work. There are some chip-scale sensors being worked on to give mobile phones inertial nav, but given the fact that we've built a load of gravity field generators everywhere (ie buildings) such sensors are doomed to drift no matter how good they are.
@@jameshatton4211 Brocken, the highest peak in the Harts/Harz mountains was where it was first documented. A Brocken spectre is where your shadow gets projected in the mist with a halo round it. Usually bigger than usual and very impressive. And, yes, the Soviets had a listening station on the Brocken and NATO also had one in the Harz on the Stoberhai.
When Rebecca was asked if she had a weight, she really should have looked at her wrist and said "How long". These write themselves you know, and you should always take advantage.
Funny coincidence: I was in Rome for the last four days (hence why I am only watching this today), and when I walked from the centre (Piazza di Spagna / Fontana di Trevi) to Termini station, I felt how hilly Rome was. A fact that I had forgotten. Because I am pretty well with orientating myself, with and without the help of maps, and therefore mostly check the general geography beforehand. On a regular map, such as Google Maps, that is. And that doesn't show contour lines. Which I remembered were a thing. And which I actually had learned about back in school. But as I never used such maps, I forgot how to read those. Especially as contour lines aren't included in regular maps. I assume, I am not the only one, who unlearned how to read contour line maps. So I wanted to ask - or suggest to - you, Paul and Rebecca, whether you could do a video about contour lines and how to read them. (Funnily enough, you have just published this video on how the contour lines came about. However, I still wouldn't consider this a "How to read a contour lines map" video imho. Not sure, whether you'd agree or not.)
Wow! One of your best videos ever! Very entertaining and informative. Id never even heard of that guy Neville before! Could we have more videos like this one if possible, please? Great to see Rebecca again as well, you work well as a team! 👍🙂
You should have gone to Schiehallion, It's one of the easiest Munros to climb and it's in a beautiful location, I should know, It's on my Ancestors lands :)
Now that, I didn't know. Thank you guys, I had always taken contour lines for granted, never once considering how they came about and who did it. Great bit of research. The history of the inestimable OS map is not only longer than most people think, but as fascinating as a good whodunnit.
Really liking this new format. You have really developed an entertaining as well as informative style. Top marks for this one (although don't test me on any of the mathematics and calculations!).
Very interesting. I once helped my son to do a reverse. From the contour lines we build a hill! It was a school project and I photocopied a large scale map multiple times and then cut out each contour and glued to cardboard. Stating with a flat plan, each layer was then glued in turn. Of course the vertical scale was different to the horizontal scale. The location was Vernham Dean in North West Hampshire, situated in the middle of a steep valley of the North Wessex Downs. It's not far from the Roman Road called Chute Causeway and the tripoint of Hampshire, Wiltshire and Berkshire. The highest hill being Haydown Hill aka Fosbury Hill with its iron age fort. PS In the video the view from the hill at 3:19 looks like one can see Highclere Castle, used for many historical films including Downton Abbey.
I missed one thing in this story. As they measured deviations of plumb lines, what was the reference they compared it to? I assume they used optical means (theodolites) to compare directions over a large distance?
I didn't know that, but I do now! I know Beacon Hill quite well though. Even when I was a lot fitter, that climb was a challenge. I think the fitter me used to go up a lot faster...
Yup, the days of the polymath where an astronomer/mathematician/physicist is also an Architect. Now we're so into 'specialization' the guy that takes my order at a coffee shop isn't allowed to make coffee because he's not a 'Barista'.
Spirit level or, better, a U tube? The plumbline decouples the gravity of the mountain from the combined gravity of the planet, which it opposes with the internal tensile force of string.
Contours allowed the concept of a '300-foot contour canal' from Newcastle (and Wales) to London en.wikipedia.org/wiki/Grand_Contour_Canal Not built of course but what an idea !
At 4:46, did they also come up with designs for the first roller coaster? 😜 I quite often take a staple gun with me when out, but I’m a planning officer and we need some way of attaching site notices to things!
It's amazing that they could come up with a method to measure the density of the planet at a time when they couldn't work out that large birds can fly a long way. (Spoiler: barnacle geese don't hibernate under water)
The question this brings to my mind is, "How do you determine in the field what straight up is without using gravity?" Since this experiment was intended to test gravitational effects, gravity could not be the frame of reference. My best guess would be to use a clock, the sun, and a protractor. You'd have to know what clock time is solar noon at that longitude and on what date the sun is straight overhead at solar noon at that latitude. You could then use that to determine what straight up is in relation to the rotation of the Earth and your position on it by measuring the angle of shadows with adjustments according to the current clock time/date. It seems a very difficult thing to do, considering how fuzzy shadows are.
@@pwhitewickthat doesn’t work, as “perfect level” is defined as perpendicular to a plug - for many practical purposes. No, what they used was astronomical references. The angles are incredibly tiny, and the errors are therefore significant. That doesn’t mean it wasn’t worth doing, as before that, there was no information!
Thanks for this. Fascinating and informative as usual, but I was a tad surprised that at no point were the obligatory white lab coats and horn rimmed glasses donned during the delivery of this scientific-ish video.
Thanks both, but think Rebecca missed a trick by not first producing a plum from her rucksack for the plumb line rather than going straight for the stapler. Love the double act though.
Newton saying that it would be impossible to measure the gravitational effect of mountains reminds me that Einstein thought that gravitational waves could never be detected because the effect was so weak. So these two titans of gravitational theory were proven wrong by human ingenuity...
As a career user of contour lines, bravo! I do have a question…or is it three…four? What is the reference to know if a plumb line is leaning? A level, straight staff, and a tape measure? We’re the tools calibrated to the standards hoarded across the Channel? Did you have to best the Black Knight at any point on your crossings of streams to reach Beacon Hill? Ah, wait. Scratch that above…just the rantings of a genetic Scot, displaced across the pond, lost among the untold thousands of contour lines which make my favorite wrapping paper. Carry on!
One point that wasn’t clarified was if the plumb bob is pulled towards the mountain, how can you establish a vertical datum point to the zenith in order to calculate the deflection? Since the mountain is exerting a gravitational pull on every nearby object, nothing that relied on gravity to establish a vertical line could work. At the very top of a symmetrical mountain, all the forces should add up to essentially point between the zenith and the centre of the Earth, but how do you do the measurements elsewhere?
"...and he noticed something quite spectacular. (Insert Revelation music)" TH-cam - "Insert advert with least sounding revelation music possible..." Thanks for such an interesting, "short & moderately quirky video" - great wording considering that a synonym for "Quirky" is 'Off-centre', which they were measuring with their plumb-line. (Although wouldn't it have been easier to simply go down to their nearest branch of WHSmiths & bought OL49 Ordnance Survey Map of Pitlochry & Loch Tummel?) I do disagree with one thing though - water depth was originally measured with a "Lead-line' rather than a plumb-line. The line being marked off with knots, & telltales to indicate depth in fathoms (6-foot intervals) and the lead weight on the end usually had a hollow base filled with tallow onto which a sample of the seabed stuck, thus giving an indication of what the seabed consisted of (which helps when picking a good anchorage).
Schiehallion is the only Munro that appears on 3 OS Landranger sheets: 42, 51 and 52 (but not 49). "Plumb" comes from "plumbum" - the Latin for lead - so plumb line and lead line are the same thing.
Not so easy "Mount Sunflower, while the highest natural point in the state in terms of elevation, is virtually indistinguishable from the surrounding terrain"
I've always found contour lines a very elegant and practical solution, but never really gave a thought to the invention. After seeing one map with them, I almost immediately made an imaginary one. They've made me love geographic maps more than any maps without them. I was hooked for life.
To thank you, I'll make a donation for that trip.
🙏🙏
These are the little-known mountains of Berkshire - 'The Himalayas of the Home Counties'. Very few visitors have explored them, because they are usually concealed by a low hedge. But the actual Schiehallion is wonderful, because it can be climbed without ropes or crampons or any technical skills - you just keep walking and clambering until you reach the top. Hard work, but well worth the effort.
It can be done without employing sherpas? Intrigued! We shall endeavor to form an expedition and establish base camp at once. 😊
You might need an ice axe and crampons in winter though. In good weather it's a straightforward climb.
?
I'm one of those geeks who likes my fiction silly. (Hitchiker's Guide to the Galaxy is a good example.) Seeing the phrase "concealed by a low hedge" appied to something called "the Himalayas" has made my day!
@@Summers-lad You have a fair point. I was there in June, as opposed to Winter (as Billy Connolly would say.)
It’s so difficult to decide which is the more entertaining. The information you convey, or the ‘Paul and Rebecca double act’. Whichever, your videos are always worth a look.
Don't you just love a complementary couple as roll models? 😎
Well, I remember learning all about contour lines a long time ago, a very long time ago, but no one taught me the history until today. Thank you Paul and Rebecca!
"Who's on Mount Rushmore?"
"Three surveyors and some other guy."
(You'll never guess what I do for a living.)
Wonderful work, you two. Thank you.
Are you a librarian?
Or a nude model?
When I was at school / college I hated history, not just the content but the delivery that was so dry. Since I have been watching all your vlogs I appreciate the subject so much more. In addition having done numerous outdoor courses etc I now the background of contours. So thank you
Fascinating vid you two.
Contour lines were vital to canal and railway building to avoid major civil engineering works.
There we are, back to canals again.
Keep it going.These presentations are amazing. Thanks xxx
The biggest question this video has to be, why did Rebecca have a staple gun in her bag at the top of Beacon Hill?
In case she was attacked by a swarm of bees ?!! 😅😅
You've heard of extreme ironing, well I have my suspicions that Rebecca is performing extreme upholstery!
Setting up lost my cat leaflets. Otherwise they would have used the cat.
A staple gun??? Loved that random bit. Oh you two play well together. Loved it.
Fabulous, I've always loved looking at contour lines and drawing the elevations. Nerdy I know, but that's the love of maps.
As a mountain biker, and map nerd, I spend a lot of time looking at contour lines for places to ride my bike.
This is a really intersting bit of knowledge that I probably would of never heard of, thank you.
Very interesting. Great fun. Rebecca is comical with her expressions. But seriously very informative. Thank you.
Rebecca of the many expressions - particularly when Paul is talking....
Expressive is good. Useful for acting, especially.
Rebecca's gurning is what makes these videos.
You two are brave peeps wearing shortened leg garments, lots of ticks this year.
Always check for ticks after.
What a treat! Rebecca, Paul, a nod towards calculus, gravity, and a staple gun.
What if Newton had a staple gun 🤔
Sir Isaac Newton would have been able Mechanically pin pieces of paper together and amaze his friends.
PERHAPS
Cheers from Australia 🇦🇺 👍
If Newton had a staple gun he could have used the side of a giant's head as a notice board.
Newton had nails & doubtless staples (of the kind found on doors), so if he was just able to lay hands on a 'kinetic modification device'!
@@pcka12 Also known as a linear impact driver!
But just imagine if he had had Paul and Rebecca as assistants!
He came close to inventing the staple gun. He invented the cat flap.
There is a similarity. If the thing that is supposed to go through them gets stuck, there's a nasty sharp thing to dislodge (with difficulty) before it can be used again...
Always wondered who “started” contour lines on maps. Thanks both 😊
If I were to be cynical, who me?, the modern revisionists of history will tell you an African American or Caribbean got there first! 😂
Contour lines beneath the sea are called soundings.
@@chrisstephens6673Oh, dear…are we feeling threatened by historical realities? Seems so, as nobody is making up history to favor those groups you surely selected at random and without any underlying bigotry.
@@jacksons1010 indeed not, just upset that history has to be fabricated in the aim of inclusively.
@@chrisstephens6673To be fair, most of the history we learned in school was heavily biased by colonial thinking, racism and sexism, and empire building mentalities, so it's good to learn the bigger picture about the women and coloured people who worked behind the scenes and previously received no credit or recognition for their work. 🙏
These two are quite fun and adorable to watch. Great communication skills and very educational. Thanks for this!
I can't figure out what is more fascinating your video of the discovery of contour lines or what ever Rebecca has in her knapsack 😊
What a disastrous game of Whitewick bingo that was! No mention of Roman roads, railways, canals... portals...and no doodbledoos!
Awks
Loving Rebecca's faces! 😊
So expressive aren't they?
Is no one going to mention the gravitational effect and natural display of contours shown by the Hillfort?
Good call
Thank you Paul and Rebecca, that was bloody interesting, short and sweet. I like your longer vids too, obviously.
Modern gravity meters are portable, and relatively robust bits of kit (airborne surveys are also done). The principle involves measuring acceleration, and the common unit is the "gal" (after Galileo), 1 of which which is equivalent to 1 centimetre per second squared.
Variations around the place, (including in Berkshire, I'm sure!) are measured in milligal, and occasionally, microgal.
And hence the reason why precision drift-less inertial positioning / navigation won't work. There are some chip-scale sensors being worked on to give mobile phones inertial nav, but given the fact that we've built a load of gravity field generators everywhere (ie buildings) such sensors are doomed to drift no matter how good they are.
Schiehallion, the fairy hill. The only time I've seen a Brocken spectre was on Schiehallion.
Pity Rebecca wasn't with you. You could've borrowed her stapler to fix it back together
Brocken not Broken? Brocken the Soviet spy station?
@@jameshatton4211 Brocken, as in the Harz mountains. No doubt there will be a play on Hart now. Oh deer.
@@BrokenBackMountainsoh really? Very ironic, Brocken Soviet spy station was on top of a hill also?
@@jameshatton4211 Brocken, the highest peak in the Harts/Harz mountains was where it was first documented. A Brocken spectre is where your shadow gets projected in the mist with a halo round it. Usually bigger than usual and very impressive.
And, yes, the Soviets had a listening station on the Brocken and NATO also had one in the Harz on the Stoberhai.
Can I just say that the non-human edited automatic subtitles are absolutely hilarious! Bravo! I have been poor.
When Rebecca was asked if she had a weight, she really should have looked at her wrist and said "How long". These write themselves you know, and you should always take advantage.
Interesting topic! Thanks
Funny coincidence: I was in Rome for the last four days (hence why I am only watching this today), and when I walked from the centre (Piazza di Spagna / Fontana di Trevi) to Termini station, I felt how hilly Rome was. A fact that I had forgotten. Because I am pretty well with orientating myself, with and without the help of maps, and therefore mostly check the general geography beforehand. On a regular map, such as Google Maps, that is. And that doesn't show contour lines. Which I remembered were a thing. And which I actually had learned about back in school. But as I never used such maps, I forgot how to read those. Especially as contour lines aren't included in regular maps.
I assume, I am not the only one, who unlearned how to read contour line maps. So I wanted to ask - or suggest to - you, Paul and Rebecca, whether you could do a video about contour lines and how to read them.
(Funnily enough, you have just published this video on how the contour lines came about. However, I still wouldn't consider this a "How to read a contour lines map" video imho. Not sure, whether you'd agree or not.)
He really put contour lines on the map!
Thanks
Thanks both ... That was a fascinating insight to something we just take for granted
Wow! One of your best videos ever! Very entertaining and informative. Id never even heard of that guy Neville before! Could we have more videos like this one if possible, please? Great to see Rebecca again as well, you work well as a team! 👍🙂
Very interesting bit of cartographical history
An interesting tour today. A good explanation of the views shown. Very interesting to view! Thank you Paul and Rebecca! See you on the next! ❤❤😊😊
You should have gone to Schiehallion, It's one of the easiest Munros to climb and it's in a beautiful location, I should know, It's on my Ancestors lands :)
Now that, I didn't know. Thank you guys, I had always taken contour lines for granted, never once considering how they came about and who did it. Great bit of research. The history of the inestimable OS map is not only longer than most people think, but as fascinating as a good whodunnit.
Really liking this new format. You have really developed an entertaining as well as informative style. Top marks for this one (although don't test me on any of the mathematics and calculations!).
Likewise!
OK, that was very interesting... and I now have the urge to go to that hill and clean that grave...
I think he helped build the railway that was once at the foot of that hill
Very interesting. I once helped my son to do a reverse. From the contour lines we build a hill! It was a school project and I photocopied a large scale map multiple times and then cut out each contour and glued to cardboard. Stating with a flat plan, each layer was then glued in turn. Of course the vertical scale was different to the horizontal scale.
The location was Vernham Dean in North West Hampshire, situated in the middle of a steep valley of the North Wessex Downs. It's not far from the Roman Road called Chute Causeway and the tripoint of Hampshire, Wiltshire and Berkshire. The highest hill being Haydown Hill aka Fosbury Hill with its iron age fort.
PS In the video the view from the hill at 3:19 looks like one can see Highclere Castle, used for many historical films including Downton Abbey.
Yes you can, surprisingly clearly. The view from Beacon hill, or at least, that particular Beacon hill, is amazing.
I missed one thing in this story. As they measured deviations of plumb lines, what was the reference they compared it to? I assume they used optical means (theodolites) to compare directions over a large distance?
Perhaps calibrated in Norfolk
I didn't know that, but I do now! I know Beacon Hill quite well though. Even when I was a lot fitter, that climb was a challenge. I think the fitter me used to go up a lot faster...
comedy gold lol , really well done and thank you Paul and Rebecca 😊😍
If the plumb line tilted towards the mountain, how did they measure the angle against the plumb line that didn't?
They used astronomical observations to determine the point directly overhead, which gave them a true vertical.
@@CharlesStearman Ho, Ho...
Never mind the science/history lesson, Rebecca carries a staple gun in her bag. Kudos for this lady. [Insert standing ovation music here].
Tis a deep bag
@@pwhitewick LOL
Great job guys! Reminds me a bit of the old James Burke TV series Connections. 😁
You are still getting better and better
Thanks Kate
Thank's for the lesson! Perhaps this might suggest a video on contour lines on OS maps? There must be a quicker way.
Beacon Hill, Burghclere, Hampshire, is that the part of Berkshire they mean?
Who takes a staple gun on a walk? Very interesting video. I've been up Schiehallion. Nice mountain.
You don't????
Today I learned why you take a staple gun into a field!
Clever stuff, thanks very much.
Fascinating! thankyou Paul and Rebecca
Great to hear about how these things got started.
Nice short entertaining video. Some lovely mountains in Berkshire! 😂
Who knew?
Fascinating both! 😊
Excellent. Very very interesting and informative. Thank you both very much.
Yup, the days of the polymath where an astronomer/mathematician/physicist is also an Architect. Now we're so into 'specialization' the guy that takes my order at a coffee shop isn't allowed to make coffee because he's not a 'Barista'.
Really informative as always. I have always wondered how they measured the angle of the plumb line? What was their datum?
Spirit level or, better, a U tube? The plumbline decouples the gravity of the mountain from the combined gravity of the planet, which it opposes with the internal tensile force of string.
They used astronomical observations to determine the point directly overhead, which gave them a true vertical.
Cheers. I think a spirit level relies on gravity in the same way as a plumb line. Astronomical observations seem the most likely.
I loved the video and the science, very educational. Just wanna check - I'm pretty sure that Beacon Hill is in Hampshire.
Expect there are loads of 'em. 1 wouldn't be much use for relaying signals.
Beacon Hill defo is in Hants according to my OS map!
Still an excellent watch though :)
Contours allowed the concept of a '300-foot contour canal' from Newcastle (and Wales) to London en.wikipedia.org/wiki/Grand_Contour_Canal Not built of course but what an idea !
Oh yes... we did a video on that a few years back.
At 4:46, did they also come up with designs for the first roller coaster? 😜
I quite often take a staple gun with me when out, but I’m a planning officer and we need some way of attaching site notices to things!
“I’ve got a staple gun”! Pa ha ha. I’ve just spat my coffee out!
Meters cubed? Sounds strange. Cubicmeters is what we say in Germany.
We probably say it here too... I'm not thw brightest
Paul, I have enjoyed following, I really hope you would teach and inspired youngsters. maybe you do, great deliveries
Very interesting, I didn't know that, something I just didn't think about. Thanks
That was really fascinating. But I can't be the only person wondering why Rebecca takes a staple gun on hikes.
I'm too scared to ask
@@pwhitewick
It's amazing that they could come up with a method to measure the density of the planet at a time when they couldn't work out that large birds can fly a long way. (Spoiler: barnacle geese don't hibernate under water)
The question this brings to my mind is, "How do you determine in the field what straight up is without using gravity?" Since this experiment was intended to test gravitational effects, gravity could not be the frame of reference.
My best guess would be to use a clock, the sun, and a protractor. You'd have to know what clock time is solar noon at that longitude and on what date the sun is straight overhead at solar noon at that latitude. You could then use that to determine what straight up is in relation to the rotation of the Earth and your position on it by measuring the angle of shadows with adjustments according to the current clock time/date. It seems a very difficult thing to do, considering how fuzzy shadows are.
Thanks Rebecca, Paul, and Skylarks!
That was incredibly interesting thanks. Thanks for share. Please take care
I've never grasped how they measured the deflection of the plumb line. Any instrument used to record it would also be affected by the same attraction.
I guess but not if the instrument was fixed to the ground at a perfect level.
@@pwhitewick They used astronomical observations to determine the point directly overhead, which gave them a true vertical.
@@pwhitewickthat doesn’t work, as “perfect level” is defined as perpendicular to a plug - for many practical purposes.
No, what they used was astronomical references. The angles are incredibly tiny, and the errors are therefore significant.
That doesn’t mean it wasn’t worth doing, as before that, there was no information!
My question is: what did they measure the plumb line deviation against? E.g. what was their vertical reference? Usually, you would use - a plumb line.
I want to know how they measured the difference of the plumb line from vertical. Usually the plumb line IS the vertical reference.
That was a major issue. Ultimately, astronomy.
Would they not have calibrated in somewhere like... Norfolk?
Thanks for this. Fascinating and informative as usual, but I was a tad surprised that at no point were the obligatory white lab coats and horn rimmed glasses donned during the delivery of this scientific-ish video.
Thanks both, but think Rebecca missed a trick by not first producing a plum from her rucksack for the plumb line rather than going straight for the stapler. Love the double act though.
Scotland: "Wind, rain and weather" - you forgot the *_midges_*
Oooh yes
@@pwhitewickThat'll be where that 20% went, balancing the mass of the airborne midges.
And NOW it's a sunday . . . :)
Thanks for this
Newton saying that it would be impossible to measure the gravitational effect of mountains reminds me that Einstein thought that gravitational waves could never be detected because the effect was so weak. So these two titans of gravitational theory were proven wrong by human ingenuity...
Love it
As a career user of contour lines, bravo! I do have a question…or is it three…four?
What is the reference to know if a plumb line is leaning? A level, straight staff, and a tape measure? We’re the tools calibrated to the standards hoarded across the Channel? Did you have to best the Black Knight at any point on your crossings of streams to reach Beacon Hill?
Ah, wait. Scratch that above…just the rantings of a genetic Scot, displaced across the pond, lost among the untold thousands of contour lines which make my favorite wrapping paper. Carry on!
I believe astronomical observations were used to determine the exact position of the zenith and hence a true vertical at each observation point.
Fascinating stuff
Another good one and I learned a lot from this one very interesting
"Is that a fact, how very interesting?" But actually it really was. Keep it up guys
Beacon Hill, Burghclere, Hampshire, is that the part of Berkshire you mean?
British maps are a reason to be proud 🙂
Agreed. To a degree. I mean... the fact I was born here is just pure luck... so I can't really take credit. I'll celebrate it though.
I want to know how did they measure the deviation from the vertical ?
Big ole instrument. Can't recall its name.
@@pwhitewick Why isn't "Big ole instrument" affected by the mass of the mountain.
One point that wasn’t clarified was if the plumb bob is pulled towards the mountain, how can you establish a vertical datum point to the zenith in order to calculate the deflection? Since the mountain is exerting a gravitational pull on every nearby object, nothing that relied on gravity to establish a vertical line could work. At the very top of a symmetrical mountain, all the forces should add up to essentially point between the zenith and the centre of the Earth, but how do you do the measurements elsewhere?
Presumably they calibrated the instrument in Norfolk
Are you now in hiding from Jay Foreman and Mark Cooper-Jones? excellent video btw!
"...and he noticed something quite spectacular. (Insert Revelation music)"
TH-cam - "Insert advert with least sounding revelation music possible..."
Thanks for such an interesting, "short & moderately quirky video" - great wording considering that a synonym for "Quirky" is 'Off-centre', which they were measuring with their plumb-line. (Although wouldn't it have been easier to simply go down to their nearest branch of WHSmiths & bought OL49 Ordnance Survey Map of Pitlochry & Loch Tummel?)
I do disagree with one thing though - water depth was originally measured with a "Lead-line' rather than a plumb-line. The line being marked off with knots, & telltales to indicate depth in fathoms (6-foot intervals) and the lead weight on the end usually had a hollow base filled with tallow onto which a sample of the seabed stuck, thus giving an indication of what the seabed consisted of (which helps when picking a good anchorage).
Schiehallion is the only Munro that appears on 3 OS Landranger sheets: 42, 51 and 52 (but not 49).
"Plumb" comes from "plumbum" - the Latin for lead - so plumb line and lead line are the same thing.
TY 🙏🙏
Fascinating stuff, I feel a little smarter after that😊
Very interesting. I learned a lot. Thanks.
A great video and some great scientific history
Assume this is slightly different to weighing the earth - as local born (local to me - Monton, Manchester) John Henry Poynting's blue plaque states
What about those Blurred Lines?
"Insert revelation music" and just at that split second an advert for dog food came on. Spoilt the moment!
how do you measure a change in a plumb line if you cant use a bubble ?
I guess a delicate instrument with a measured angle change on it
Local “true” vertical established by astronomical measurement.
Mt. sunflower in kansas would've worked for his experiment as it's by itself was left behind by the Rockies.
Not so easy "Mount Sunflower, while the highest natural point in the state in terms of elevation, is virtually indistinguishable from the surrounding terrain"
Where were you walking when you filmed this please?
North of Whitchurch in Hampshire.
very cool that might make a cool movie.
Lovely Views 🙂🚂🚂🚂