Plate III: Elevation of the Scaffold used at Gravelines. Scale 10 feet to an inch. (to accompany) Extension of the triangulation of the Ordnance Survey into France and Belgium ... 1863.

Uncolored view scaffold.
Printed in vi, 62 pages, with 7 plates. Includes table of contents, text, and manuscript letters and notes. Accompanied by 21+2 pages of text, note and figure, titled: Sur l'Influence des attractions locales dans les Operations Geodesiques ... Par Le General de l'Infantierie T.F. de Schubert ... Altona, 1860. Bound in light brown leather covers, with "Extension of the triangulation of the Ordnance Survey into France and Belgium" and a decorative border stamped in gilt. Noted in introduction: "All computations here given have, been made by or under the immediate superintendence of Captain alexander Ross Clarke, R.E."