After much scratching of heads, one soldier solves the problem by getting an axe and chopping down the pole. His mates then measure it as it lies on the ground.
“Twenty foot and seven inches, sir!” they report to the sergeant-major who goes red in the face with anger.
“I told you I wanted to know its height, not its length!” he bawls.
I mention this because when I was at junior school, we were taught how to measure the height of a tree using a protractor fixed to a ruler and with a piece of string weighted with plasticine to make a clinometer.
Using this rudimentary instrument, you could measure the angle when looking along the ruler aimed at the top of the tree. Next you used graph paper to create a scale drawing not unlike the one above and, voila, you could work out the height of the tree.
I think this lesson was to introduce us to the practical uses of geometry, but to me it opened up a whole new way of seeing the world and I spent many happy hours using my new-found skill to measure the height of everything in sight — telegraph poles, lamp-posts, the town hall etc.
It was the start of my interest in geography. Not the boring stuff — the population and principal export of Germany, or the average annual rainfall in the Atacama Desert, that sort of thing — but the practical geography that lets you see the world around you with new eyes.
I really enjoyed the field trips to places like Malham in North Yorkshire to look at limestone pavements and work out where the glaciers had once gouged out a valley.
But most of all, it was the ordnance survey maps that intrigued me with their symbols for spot heights, windmills (with or without sails), battlefields, non-Roman castles and the like. And how you could use the contour lines to draw a cross-section of the terrain between one point and another.
Mrs P is another geophile, at least when it comes to maps. She is the official keeper of the pink-covered OS Landranger map on her Saturday walks, wrapped in its plastic rain cover. And when we drive any distance, she’d much rather follow our progress on a road atlas than the sat-nav so she can see what lies round and about.
It is quite a weighty tome, as befits such a crucial item as a map that is an accurate and reliable representation of the world about us.
Which brings me back to where I started. I’ve been dipping into the book and it makes you realise what a great undertaking it must have been for the early map-makers to look across the landscape and then at the blank piece of paper they had to fill.
Their tools might not have been quite so rudimentary as my protractor, ruler and string and plasticine, but someone would have had to create the instruments to complete the project.
Think about it. Where would you begin? Just how well do you know the places you think you’re familiar with?
When I was younger, I would amuse myself by drawing maps of places I knew without leaving my room. Invariably it was wrong. The roads wouldn’t quite meet up in the way they should, or the scale would go awry. It really isn’t easy.
Left is a section from the 1897 OS map roughly centred on my house which you can click to enlarge. (The map, not the house.)
You can see that George Lane dog-legs to the left just north of centre and then curves gently right. In my version, I had it much straighter so that it finished up where St Mark’s graveyard would be.
I mentioned a challenge in the title and here it is — to try drawing a map of the area around where you live and then comparing it with Googlemaps or whatever to see how accurate you are.
How wide a radius is for you to decide, depending on the complexity of the geography of your locale. I’d be interested to hear how you get on.