George Frederick Charles Searle (1864-1954) was a British physicist who worked at the Cavendish Laboratory at Cambridge for 55 years. Originally published in 1925, this book describes optical experiments carried out in Searle's practical class at the Laboratory. A broad range of experiments is contained, reflecting the diversity of student experience within the classes. Illustrative figures are incorporated throughout. This book will be of value to anyone with an interest in optics and the history of science.