Reviewed by: Sparks and Flames: Ignition in Engines—An Historical Approach* Ray E. Hooley (bio) Sparks and Flames: Ignition in Engines—An Historical Approach. By Crawford MacKeand. Montchanin, Del.: Tyndar Press, 1997. Pp. viii+168; illustrations, figures, notes, bibliography, index. $14.95. It has been a pleasure for me to review Sparks and Flames. It is a book written by an old-engine enthusiast for old-engine enthusiasts. The very readable text traces the development of engine ignition systems from the 1600s to recent times. It describes and analyses all forms of spark and flame ignition, but stops short of electronic systems and deals only briefly with compression ignition. Crawford MacKeand’s own special interest in old machinery, especially engines, is evident in his practical approach to the subject. Fellow engine buffs will find it both interesting and of great help to them in dealing with the various problems that they encounter in their hobby. I expect it to become a popular reference book on the workshop shelf. The earliest designs of gas engines used very crude forms of electrical spark ignition. By the early 1800s, however, flame ignition had gained prominence, despite the fact that the first commercially successful internal combustion engine, the Lenoir, employed electrical spark ignition. Chapter 2, the historical section of the book, examines the successes and failures of the large variety of the relative systems. Engineers strove to improve on external-combustion engines (e.g., steam engines). Experiments included the hazard of exploding gunpowder in confined spaces. The resulting release of energy had to be tamed. Chapters 3–7 describe flame and electrical spark ignition systems in detail. Many good-quality illustrations show the evolution of the mechanics of flame cocks, valves, hot tubes, hot surfaces, induction coils, electromagnets, low- and high-tension magnetos, low- and high-tension spark plugs, igniters, distributors, condensers, contacts, and so on. This main body of the book will be most useful to college students, mechanics, engine restorers, and historians. The reader is helped by the author’s liberal use of contemporary detailed illustrations and his efforts to follow the progress of developments in specific topics, while at the same time maintaining the chronological sequence of events. Since the book is essentially a practical study of the subject, advanced students who are more concerned with the theoretical aspects will find little not available in standard textbooks. For them it will serve more as an overview of the many facets of the ignition process. A separate chapter considers the supply of energy for ignition. After a brief mention of flame ignition, which relies generally on burning gases or liquid fuels, MacKeand moves on to the much wider field of electrical ignition. Static electricity was used in the earliest systems. The need for better control of the spark brought the development of batteries and induction coils. Dynamos were required to charge the batteries. Where less bulky systems were required, magnetos provided the power for spark ignition: low-tension [End Page 687] magnetos with igniters and high-tension magnetos with spark plugs. A short chapter on compression ignition describes hot bulb (semidiesel) oil engines, which worked by compression ignition after initial heating of the combustion chamber by external heater. The first successful oil engine, the Hornsby-Akroyd, paved the way for the cold-start compression-ignition engine of Rudolf Diesel. Diesel employed much higher compression ratios than Akroyd-Stuart, the latter preferring to build the safer low-compression models. Worldwide sales of around forty thousand Hornsby-Akroyd engines from 1892 to 1914 rewarded this decision. In later years the higher-compression engines became standard. The oil engine quickly replaced the gas engine for large power requirements and where the use of safer heavy fuel oils was paramount. Another short chapter on ignition theory gives some surprising, and very interesting, facts and figures concerning combustion reaction rates. The nature of sparks is examined, showing the importance of their size to the combustion process. The mysteries of knock and preignition are explained, as is the sequence of events in an electrical spark ignition system. MacKeand concludes with a chronological table and a detailed and very useful bibliography. This book is a must for stationary engine...