The slide rule : $b a practical manual

"The Slide Rule: A Practical Manual" by Charles N. Pickworth is a technical manual written in the early 20th century. The book is aimed at readers who wish to understand and effectively use the slide rule, an analog mechanical device for performing mathematical calculations. It covers the fundamental principles of logarithms and mechanical calculation, as well as the practical aspects, techniques, and various types of slide rules used for technical and engineering computations. This manual is intended for students, engineers, and anyone interested in the theory and application of slide rules. The opening of the manual begins with a series of prefaces noting updates in new editions, emphasizing the inclusion of special slide rules and recent applications such as screw-cutting gear calculations. The content proceeds to a concise introduction to slide rules, explaining their function as tools for mechanically doing calculations based on logarithms. Pickworth starts by demystifying logarithms and demonstrating their close relationship to the slide rule’s function, illustrating both arithmetical and mechanical principles behind the instrument. The text introduces the reader step-by-step to the concepts of notation by powers of ten, the construction and use of the slide rule, and how its unique scales operate. Early chapters provide practical instructions for multiplication, division, reading scales, using the cursor, and understanding the notation and number of digits in results. The author ensures clarity by incorporating worked examples, practical hints, and a logical progression from basic to more advanced operations, making the material approachable for both beginners and those seeking to deepen their expertise with the slide rule.