A treatise on mathematical instruments, including most of the instruments employed in drawing, for assisting the vision, in surveying and levelling, in practical astronomy, and for measuring the angles of crystals. In which their constuction, and the methods of testing, adjusting, and using them, are concisely explained / By J.F. Heather.

Licence: Public Domain Mark

Credit: A treatise on mathematical instruments, including most of the instruments employed in drawing, for assisting the vision, in surveying and levelling, in practical astronomy, and for measuring the angles of crystals. In which their constuction, and the methods of testing, adjusting, and using them, are concisely explained / By J.F. Heather. Source: Wellcome Collection.