If you hike up Mount Kearsarge you are likely to see several names carved into the granite. One carving is a square with seven names and the initials USCS and the date 1872. That carving was done by a team known as the United States coastal survey and it's meant to memorialize the work they were doing, which was to build an early modern map of New Hampshire.
For more on this we turn to Granite geek David Brooks who has been writing about this for the Concord Monitor.
So chief among those names carved into that box was Professor E.T. Quimby. Who is he?
He was a Dartmouth professor of geology, approximately, who basically got the contract to do this kind of mapping in New Hampshire. U.S. coastal survey was established sort of after the War of 1812. The U.S. realized that it needed better maps of the coast because ships kept running aground. Started doing it and then its usefulness became obvious and there was mission creep, if you will, and the mapping expanded away from the coasts and eventually covered the whole country. And in 1860-1870, they were doing it in first Massachusetts and then New Hampshire, and as I say, Professor Quimby sort of got the contract to do it, to lead the team in New Hampshire.
And what exactly was he doing on Mount Kearsarge?
What was he doing on Mount Kearsarge? Besides carving his name into the rocks, which we frown on these days, by the way. He had a team of a lot of Dartmouth undergrads and other folks working with them. And what he was doing was he'd chosen a bunch of mountains around the state and he would go up under the top of each one of them and set up 15-foot poles with a nail keg on top, painted black, and the poles were painted black and white. And then he would have a team on another mountain that would be observing this pole, and he would observe the pole on the other mountains. And he would use these observations and surveying equipment to do his mapping -- to figure out where things were very precisely.
And he used triangulation, which is something that map makers used a lot. And how does that work? How does triangulation work?
Very simply, it's basically, you go up on these mountains, you look from mountain to mountain, you measure the angles. You know a certain distance, some set distances as a baseline using angles, and little bit of high school geometry. It's not that complicated, actually. And you can draw these monstrous triangles and if you can go look at the maps that he was created in the 1870s, you'll see a map of New Hampshire with all these triangles drawn from mountain to mountain, from Monadnock up to Crotched Mountain up to Kearsarge up to Uncanoonuc. Anyway, and of course Mount Washington and many other prominences around the state, drawing these big triangles, measuring the angles, using that little bit of mathematics to have precise distances, to really nail down where things were.
So for you to learn more about Professor Quimby you went to the state archives?
They have all these notebooks that he and his team have did for years and years writing down angles and measurements, from point to point, and not just from mountain to mountain, what they do is also go up on a mountaintop and once they sort of triangulated it then they would make angle measurements to various things they could see. You'll see this church spire. You'll see the angle measurement from Crotchet Mountain to the to the gold dome on the State House, or to the ridge pole on the barn, the Shaker barn in Canterbury.
How precise were these measurements taken by triangulation? Were they within a foot, within a yard, a few inches?
No, no, they were within a few inches, but I would say they were within a few yards. If you look in his notebooks you'll see he's got some decimal calculations that are to nine significant digits, which is kind of ridiculous. That's more significant than you possibly could, but he's measuring angles to two minutes and seconds of arc. So they were more than precise enough for the 19th century and for most of the 20th century. They are not precise enough for your GPS in your car, which is why satellites are up there doing it now.
And he wasn't the first person to try and do it this way. So what was the significance of his efforts?
Well as I say, this was the first attempt to make widespread maps, modern maps, using triangulation. Triangulation of course is still used today. I mean, surveyors still do it all the time and even the satellites going overhead use triangulation to figure out our GPS locations. But this eventually became sort of filtered down as now U.S. Geological Survey maps, really the basis of all the maps we have today. It was before that maps were made frequently by people taking trips and doing sightings, you know, doing solar sightings to figure out latitude and longitude of specific places, and then compass points and trying to sort of figure out how they were related. And there were lots of very good maps but it was hard to connect them all together. Triangulation was the way to tie everything together and create the one big map.
David, thank you very much for speaking with me about this.
That's David Brooks. He's a reporter for The Concord Monitor and the writer guaranteed to find the geekiest thing on top of any mountain he climbs at GraniteGeek.org.