Ingenium: Five Machines That Changed the World

"Ingenium: Five Machines That Changed the World" by Mark Denny is another book in the genre of popular science books about familiar objects. Denny covers the bow and arrow, waterwheels and windmills, counterpoise siege engines, the pendulum clock anchor escapement and the centrifugal governor. This might seem an odd selection of machines, given the title of the book, but Denny describes the broader relevance of these machines and their underlying physics to society. Denny covers the history and development of each machine and follow this with a more detailed discussion of important principles. He starts with a simple model of the physics of each machine to tease out important variables and to learn about the factors influencing efficiency and performance. This allows him to refine the model and make it more realistic. Such a technique is very useful and should be a part of the toolkit of all engineering and technology students, not to mention their teachers. Modelling a device is an essential first step to understanding its underlying principles. Denny then uses the insights gained from his mathematical models to illustrate how each machine developed empirically over many years as artisans and craftsmen tinkered with traditional designs to improve them - without the use of mathematics or physics. Such empirical developments led to very efficient designs - often close to optimal when checked with all the mathematical and computer tools available to modern engineers. Key equations are not derived in the text, but are simply quoted. References to the full derivations (and much else) are given at the end of each Chapter. That is fine for the general reader who may be put off by equations and physics, but the absence of derivations (even in outline) might frustrate mathematical readers. Website references are given so that readers can see some of the machines (eg clock escapements) in action. Text boxes are used to give short biographical details of key individuals involved in the development of the machines discussed. The chapter dealing with clock escapements is particularly good. There is a simple diagram that shows exactly how escapements work. Sufficient, but very simple, equations are presented so that readers can see what factors are important in escapement design and understand some counter-intuitive conclusions (eg a small amount of friction is critical to the stability of pendulum clocks). The book is a good blend of history, biography and physics. One can enjoy it by reading the non-mathematical text alone. Readers with more physics knowledge will enjoy the additional mathematical challenges. I liked this book. It is a cut above many of the books in this genre. Many of these books are fairly trivial and padded with marginal material and illustrations to bulk out the text. Thankfully, this book does not suffer from such faults. Definitely worth the money.

In this most fascinating book, the author presents a brief history as well as the basic scientific and engineering principles behind five devices (machines) that have been important in human history. Each chapter ends with a set of references for those interested in pursuing the history, the mathematics and the finer technical points more deeply. The writing style is very friendly, witty and often tongue-in-cheek; it is also very clear and authoritative. The author has endeavored to aim the book at as broad a readership as possible and I believe that he has succeeded admirably, i.e., mathematical formulas are included for clarity and to please the scientifically curious but they are not derived, keeping the math-phobic in mind. So, this book should be accessible to everyone, but will likely be most appreciated by science and engineering buffs. Personally, I found this book very pleasant to read as well as very instructive, but I think that more mathematics, perhaps included in appendices, would have made the book even more fun for those, like me, with a scientific background.