The characters at the center of The Lunar Men were all born between 1728 and 1736. They are Erasmus Darwin, doctor, mechanical wizard, botanist, evolutionary theorist and grandfather of Charles; Matthew Boulton, metal manufacturer; James Watt, a Scottish engineer who made great improvements to the steam engine and then entered into partnership with Boulton to manufacture them; Josiah Wedgwood, pioneer of mass production in pottery and leading opponent of slavery; and Joseph Priestley, chemist and dissenting preacher. Some of them met through the effort to build canals through the Midlands, in which all were involved; others were introduced by mutual connections. From 1775 to 1794 they met at each other’s houses on the Monday night closest to the full moon, so as to drive home by its light. When they met they did scientific experiments and argued over their own results, or over results and theories they read about from all over the world. Chemistry exercised them most, especially Priestley’s work on gases and the debate between Priestley and Lavoisier over combustion and the composition of matter. They also explored electricity, geology, mineralogy, botany, and medicine; perhaps the most important discovery to emerge from their circle was the effect of digitalis on the heart, identified by young doctor William Withering with Darwin’s help. They all drew on each other’s inspiration in many ways. Priestley perhaps spoke for all when acknowledged his friends in the preface to his most famous book, saying that the society was “almost an equal partner” in his work.
All of Uglow’s subjects were amazing men. Darwin was a mechanical genius, inventing among other things the gas turbine and a steering system that would one day be used in most of our cars. When an extremely bright meteor blazed a trail over Europe, he paused in his experimental gardening to triangulate its height above the earth as 58 miles, which was probably about right. His work on botany convinced him that all life was descended from a common ancestor. The discovery of evolution’s main mechanism was left to his famous grandson, but the fact of evolution was perfectly clear to him. Wedgwood brought experimental science into the potteries, drawing on chemistry and geology to perfect new kinds of ceramic and new ways of organizing labor to manufacture it faster and cheaper. His new jasper ware had to be fired at just the right temperature, but there was no technology available for measuring such heat; so Wedgwood invented one, using clay that changed color with increasing temperature. Wedgwood was a younger son who inherited nothing and started as an apprentice in his older brother’s pottery, yet his elder daughter’s dowry was £25,000. Boulton and Watt, after years of struggle during which Watt worked as a canal surveyor and Boulton spent much of his energy keeping creditors at bay, eventually emerged even richer. Their engines were mechanical marvels, five times as efficient as anything that had come before. Priestley appears in every one-volume history of science. Think what those meetings must have been like: so much scientific firepower, backed by so much experience of business and knowledge of the world, tongues loosened by real friendship. We have no records, but working from their frequent letters and their voluminous journals, Uglow gives us a sense of the wonder.
The Lunar Men is a breathtaking glimpse of the industrial revolution as it took off, and of the society from which it emerged. This group portrait of friends who shared a passion for science shows like no other book I have read the tangled connections of industry, politics, money, scientific advancement, technical progress, and sentimental family life that, in Uglow words, "nudged their whole society and culture over the threshold of the modern." It is the best book I have ever read on the eighteenth century.