Reddit reviews The Measure of All Things: The Seven-Year Odyssey and Hidden Error That Transformed the World

Given the difficulty of the terrain, I'm pretty confident they would have done it by surveying. This was about the same time George Washington was working as a surveyor in the Colonies.

https://en.m.wikipedia.org/wiki/Surveying

If you search "18th century surveying methods" there are a bunch of good sources with detailed descriptions on the first page other than the Wikipedia article.

Or if this achievement gets you excited, get a copy of The Measure of all Things by Ken Alder.

https://www.amazon.com/Measure-All-Things-Seven-Year-Transformed/dp/0743216768

It describes a roughly contemporary surveying expedition that completely dwarfs this one in ambition. It describes the techniques used in fairly user-friendly detail, and Alder is a very respected historian working from primary sources.

On a flat surface, making an accurate circle of that diameter would have been achievable since the heyday of Babylon.

Probably the best (and most accessible) book on this subject is The Measure of All Things by Ken Alder. Alder discusses the need for standardised measurements in France, where each municipality had its own weights and measures, resulting in about 250 000 different measures being in use throughout the country. It wasn't only tax officials who wanted to have a national standard for weights and measures, but also merchants, who wanted to trade with other provinces in the country; and scientists who wanted to exchange information with their peers in other countries.

A government committee decided that a ten-millionth of the Earth's circumference would be the standard for the metre. After surveying the meridian from Dunkerque through Paris to Barcelona, a metal bar was produced as a standard.

Since then, the metre has subsequently been defined as a number of wavelengths of a beam of light at a particular frequency, and now is determined as the distance light travels in a defined fraction of a second.

These changes in the definition have not meant that the length of the metre has changed. It just means that the metre is defined with more precision than was possible with previous methods. Also, they ensure that laboratories worldwide can independently make their own standards and use them to calibrate secondary standards, physical metre rulers.

I second the vote for Cartographies of time.

I might add a couple different options:
A book on Minard's hyper famous graph on Napoleon's invasion of Russia
https://www.amazon.com/Mapping-Time-Illustrated-Napoleons-Campaign/dp/158948312X/ref=sr_1_1?s=books&ie=UTF8&qid=1481581204&sr=1-1&keywords=minard

"the measure of all things" on how the metre was established
https://www.amazon.com/Measure-All-Things-Seven-Year-Transformed/dp/0743216768

and "longitude" a must read for the aficionado
https://www.amazon.com/Longitude-Genius-Greatest-Scientific-Problem/dp/0802713122/

If you want to be more original, get her a sextant replica

https://www.amazon.com/Scott-London-Sextant-Hardwood-C-3082/dp/B00L290KHQ

or maybe go to etsy and grab a laser cut wood map of her state/country
https://www.etsy.com/listing/265691544/seattle-laser-engraved-wood-neighborhood?ref=market

map people, we're easy.

From Library Journal


Most people don't think about how a mile became a mile or a foot a foot, but Alder here presents a fascinating account of how the meter the standard measure of distance for over 95 percent of the world's population became the meter. We live in an era when standard measures for objects and time have become so common that we would have difficulty imagining a world without them. Alder takes us back to revolutionary France, when it is estimated that 250,000 different units of weights and measures were in use. Written in the vein of Dava Sobel's Longitude and reading much like a historical thriller, his book follows the seven-year effort of two accomplished astronomers to measure the meridian and the curvature of the earth from Dunkirk to Barcelona. Imbued with the spirit of the Age of Enlightenment and the revolution's call for universal rights and truth, these scientists strove to create a truly universal standard. Alder's first book, Engineering the Revolution, won the 1998 Dexter Prize; his second is a fascinating and well-written work recommended for medium and large public libraries as well as academic libraries. James Olson, Northeastern Illinois Univ. Lib., Chicago
Copyright 2002 Cahners Business Information, Inc. --This text refers to an out of print or unavailable edition of this title.

This is a fascinating read...


http://www.amazon.com/Measure-All-Things-Seven-Year-Transformed/dp/0743216768/ref=sr_1_1?ie=UTF8&s=books&qid=1250780477&sr=8-1

Here's a really great book about it. Set in the throws of the French Revolution. It's a story of how the meter was formulated using triangulation by two scientists appointed by the King.

Because it was designed that way. Before the French revolution, units were a mess and could differ from town to town. Each town often had examples of their local foot, yard and gallon fixed to the town hall. At the height of the French Revolution, scientists who had suddenly been elevated to high positions decided, with revolutionary fervour, that a new regime needed a new, logical system of units. Thus they conceived of the meter - to be defined as 1/10,000,000 of the distance between the North Pole and the Equator at the Paris meridian - and derived all other units from that.

If you're interested, try this book, which has a good history of what happened back then: https://www.amazon.com/Measure-All-Things-Seven-Year-Transformed/dp/0743216768/ref=sr_1_1?ie=UTF8&qid=1469607564&sr=8-1&keywords=the+measure+of+all+things

Wrong.
The metric system was made "Legal" to do business in, but not mandatory.

http://www.amazon.com/The-Measure-All-Things-Transformed/dp/0743216768

The history of the metric system. How an error in measurement fundamentally flawed the " Meter " and is perpetuated to this day.

TLDR: The meter is several millimeters short of its intended size (1/10,000,000) of the arc of the meridian.

TLDNR the TLDNR: the metric system is all LIES!!!

Read The Measure of All Things, it will yield a little more insight into the origin of the meter and the thinking that led to it.

Ken Adler -- http://www.amazon.com/The-Measure-All-Things-Transformed/dp/0743216768

The book is fascinating! The two surveyors were expected to prove the meter was accurate to their theory. Instead they spent seven hard years only to find the earth isn't even a perfectly oblate spheroid.