The Seven Measures of the World (Yale University Press, £18.99, ISBN: 9780300266276) is a guide to the natural world through seven units of measurement: the metre, the second, the kilogram, the kelvin, the ampere, the mole, and the candela. With these seven measurements, Martin argues, we can understand the universe.
The book begins with a sketch of a moment from our recent history: 1960. Elvis was at the top of the charts, the Beatles had just formed, and, at the 11th General Conference of Weights and Measures, the SI system of measurements was adopted: "At last humanity had a coherent architecture for measurement, whose seven basic units defined a complete and universal language for measuring not only our own small world but all of nature, from the most obscure subatomic recesses to the boundaries of the universe."
Seven Measures is a collection of these critical moments in scientific history, paired with simple scientific explanations. They span all major fields of physics, as well as touching on chemistry and biology. Martin adopts a meandering approach to storytelling that reflects the messy nature of science, its resistance to being squashed into discrete categories or linear narratives of discovery and invention. Much of Seven Measures is dedicated to showing the reader how science does not take place in a vacuum, but is deeply integrated with politics, economics, and questions of state and society. In a number of passages that leave a real impression, Martin depicts great scientists making cameos in momentous historical scenes, including Einstein speaking out on civil rights in the US, and Planck's challenging audience with the new German Chancellor, Adolf Hitler.
But there are so very many sketches packed into fewer than 200 pages that Seven Measures feels cluttered: a 'greatest hits' of science. Do we really need to visit the history of vaccination in a chapter on the candela? Other times, Martin introduces topical problems – climate change, plastic pollution, unequal global access to electricity – which are not necessarily relevant to the chapter. A book can make the case that science must be paired with social responsibility without gesturing to it so explicitly.
Seven Measures is translated elegantly from Italian by Gregory Conti. The pages are adorned with black-and-white illustrations, which lend it the feeling of a popular science book from the late-Victorian or Edwardian age.
Through no fault of the author himself, Seven Measures has the misfortune of being published around the same time as the paperback version of James Vincent's masterly Beyond Measure which also examines the history of measurement, and which was arguably the science book of the year. Seven Measures is distinct, thanks to its format (seven short chapters, one for each unit of measurement), although it would have benefitted from having some passages cut – perhaps reducing it to a similar length to Carlo Rovelli's Seven Brief Lessons on Physics and setting it further apart from the competition.
A high-level introduction to physics through units of measurement, Seven Measures – despite some unnecessary digressions – would make a good gift for interested non-scientists.
