Review of The Measure of All Things: The Seven-Year Odyssey and Hidden Error That Transformed the World by Ken Alder

After a long spate of young adult novels, and in particular the very harrowing Asking for It, I needed a palate-cleanser. How much further can we get than a book about the expedition to define the metre?

I take the metre for granted. It’s just there. I was aware, vaguely, of the various ways in which it has been defined, and I knew that the metric system came out of the French Revolution. What I didn’t realize, however, is how close we came to having a different metre—or to not having a metre at all. If any number of events did not happen precisely as they did, we might still have unit chaos, or we might be using a metre that looks much different from the one we have today.

It’s this exploration of the politics around the definition of the metre that makes The Measure of All Things so fascinating. Although Ken Alder takes the time to explain some of the science and engineering that went into this expedition and its efforts, this story is ultimately about people, and how their egos and follies can shape entire generations of scientific thought.

It’s attractive to think of science as neutral or objective. Indeed, when I was younger that is often how I thought of it. While this might be a goal towards which science strives, it is naive to believe we can achieve such neutrality. Science is a process of human endeavour, and so ultimately it is vulnerable to social biases. We must acknowledge these biases and remain watchful for when they show up in our efforts. Similarly, we can’t just pretend that science is free of the influence of politics. It’s tempting to assume that science transcends national and corporate loyalties, but that is a dangerous fiction to maintain.

Probably few have been as aware of this as the scientists—or savants as Alder calls them—labouring during the French Revolution. With the political winds shifting every year, it was all too easy to find yourself out of favour—which, in this climate, typically meant losing your head. It’s also important to recognize that many of the innovations introduced at this time, including the metric system, were spurred on by revolutionary motives. Hence, politics drives and influences science far more than we might want to admit. The metric system was supposed to standardize weights and measures across France, giving the nation a renewed unity that would help solve some of the problems with taxation and commerce that had plagued the country under monarchy. Moreover, in the form of the meridian expedition, it would be a work of national pride: French savants on French soil would measure the Earth and use its glorious natural proportions to define a new unit of measurement!

And then they screwed it up.

Alder knows how to tell a tale: The Measure of All Things is a mixture of a couple of biographies and some intrigue set against the backdrop of Revolutionary France. I was fairly interested in a story of the development of the metre, but I absolutely cannot resist non-fiction that promises me scandal! intrigue! cover-ups! And this book has all of those things in spades. As Delambre makes his way through the rural villages of northern France, you hold your breath with each delay and detainment by the suspicious villagers. (The Enlightenment, of course, was a phenomenon exclusive more to the privileged and urban inhabitants of Europe. Superstition and mistrust of savants was still the order of the day, and given this context, it’s easier to understand why that still seems to be the case in parts of North America.) Likewise, the tension on the southern leg of the expedition as Méchain agonizes over his discrepancies and delays departures keeps you constantly guessing as to how everything will shake out. I mean, we know the broad strokes of how the expedition ends, but there was plenty I didn’t know.

Alder excels at providing the historical context for the astronomers’ discoveries, as well as explaining how astronomers went about actually measuring the Earth. Geodesy is cool, and if you haven’t spent much time thinking about the shape of the Earth, this book will give you a crash course in some of the innovative methods people have created over the centuries. We in the era of GPS devices are so divorced from this type of technology that it’s easy to forget that the actual methods are very basic. Delambre and Méchain were using techniques similar to what geodesers use today—we just have more precise and accurate tools.

Speaking of which, I loved Alder’s digression into the difference between precision and accuracy, and his description of Laplace’s development of error theory. Going to be honest: even as a mathematician, I don’t like statistics. But I always find it interesting how certain aspects of mathematics and science emerged (in their rigorous form at least) relatively late—Delambre and Méchain had access to a lot of good mathematical tools, but error analysis wasn’t one of them.

I also appreciate how The Measure of All Things does not succumb to the Great Man Theory of history. Yes, it foregrounds the two leaders of the meridian expedition, and Alder ascribes much of what transpires to those leaders’ particular personalities—Delambre striving for integrity and transparency, Méchain obsessed with precision and completeness. I can definitely see how the expedition might have turned out differently if, say, Cassini IV had ended up leading it. Nevertheless, Alder never supposes that these two great men were Great Men who dual-handedly put France, and the world, on the path to metric. He points to the confluence of other factors that made this the right time, right place. He highlights the work of other savants, such as Borda, Lalande, Laplace, Legendre, et al, who developed theories or devices that made the expedition possible. He also points out the diplomats and public servants who at various times helped or hindered the expedition. Finally, Alder mentions the people who supported the expedition leaders: their assistants (often very capable savants or surveyors in their own right) and family (Thèrese Méchain was a pretty cool lady, given her ability to manage the Observatory on her own and the way she just up-and-joined her husband to try to talk him away from the abyss).

At times Alder likes his digressions a little too much. Did I really need the entire backstory on Lalande? No, although I admit it was interesting. Did I really want those last couple of chapters on the metric system post-Revolution, including most of a chapter devoted to the United States? Not really. The Measure of Things is detailed and comprehensive in pursuing its topic, and as such it’s also overly long and occasionally to detailed for its own good.

I would definitely recommend this book to anyone interested in history or the scientific method. Even if you’re not that interested in learning about the inception of the metric system, this is a different approach to looking at the French Revolution that you might appreciate. Other than my criticisms about the length and digressions, Alder’s writing is remarkably clear and unassuming; he is always honest about what we know or don’t know from the evidence and correspondence he could find. Too many popular history books inject the author’s view into the conversation—sometimes that is useful or necessary, depending on the topic, but it’s a welcome absence here.

Regardless of your opinions of the metric system, it has shaped the modern world. That all started in the 1790s in France, ended in the early 1800s, and gradually came back into vogue over the next two centuries. The Measure All Things promises to trace the development of the metre as an aspirational unit based on the size of the Earth; it also promises to unmask and clarify the ways in which this aspiration went awry through human error and political machination. It delivers on both of these promises, and the result is a fascinating and enjoyable non-fiction book, the perfect palate-cleanser before I dive back into some hard-hitting YA.