James Rendel Harris was an eminent scholar of Biblical texts, best known for his discovery and editing of a great number of Syriac Biblical manuscripts. This piece describes the nature of and use of stichometry, a method by which the length, pagination, and line spacing of the original appearance of ancient documents can be calculated. Many ancient scribes preserve in their copies the stichometric marks used by authors and their copiers to estimate the amount of paper needed to write a document, and this is one of the key pieces of modern scholarship describing the process. This is of use to anyone interested in ancient autographs and the process of writing in the ancient world, and a knowledge of the subject is key to any serious study of ancient texts.