Diagram of an estimation of the size of Earth by unknown author Diagram in notes taken from a section on measuring the size of the Earth in Giambattista Riccioli's 'Geographiae et hydrographiae reformatae, nuper recognitae et auctae libri duodecim' [Reformed geography and hydrography recently revised] (1661). Diagram is of a globe with angle and measurement lines. Parts are lettered. Appears on the ninth page of the document. Subject: Astronomy 1662