The Art Of Dialling By The Gnomical Scale (1679)

This is the seventh book from Sturmy’s very popular The Mariners Magazine – a warehouse of valuable information for English mariners. Sturmy’s work originally appeared in 1669, and subsequently went through 3 more editions, “diligently revised and carefully corrected” by mathematician John Colson. This is the second edition. Sturmy’s ‘gnomical scale’ is equivalent to the dialing scales that became popular in the 17th century. (Unlike other entries in the collection, this reprint is done with modern fonts; the graphics are facsimile reproductions).