Jāmiʻ al-qawāʻid fī al-misāḥah

The text deals with the precise measurement of the size and shape of the earth, mapping points on the earth's surface, and the study of the earth's gravitational fields. The manuscript includes only three chapters on the third topic. On the last page is a note written in a different script about measuring with different kinds of cubits. This manuscript, probably dating from the 17th century, preserves only a section of what appears to have been an extensive and complete treatise on practical geometry. The title on the second page of the manuscript in fact states that it is "the third section of the book of the General Rules in the Science of Measurement." The larger work of which this is a part consisted of four introductory essays, five chapters, and a conclusion. The author is unknown, as the opening of the treatise where indications of authorship might have been found is now lost. Also not clear is whether the other sections of the book circulated in separate volumes or as part of the present one, as the numeration of the folios--beginning here with number one--appears to have been added to the text at a later date. The work contains a comprehensive syllabus of Euclidean plane geometry. The four muqaddimāt (introductions) present the reader with names and definitions of geometrical entities. The text deals with the precise measurement of the size and shape of the earth, mapping points on the earth's surface, and the study of the earth's gravitational fields. The manuscript includes only three chapters on the third topic. On the last page is a note written in a different script about measuring with different kinds of cubits. The work possibly had a didactic aim, as suggested by the numerous geometrical drawings that accompany the theoretical explanations. In many cases, these drawings in red ink are provided with captions that clarify the specific terminology applicable to the figure along with exemplifying measurements. World Digital Library.