1851 Great Exhibition: Official Catalogue: Class X.: J. B. Denton
317. DENTON, J. B., Gray's Inn Square — Inventor.
Specimens of model or relief mapping, finished and in skeleton, accompanied by a beam-level, for ascertaining heights and distances, with plans and tools elucidating the method of construction.
Model mapping is designed for the representation of districts where works of drainage and other hydraulic operations are contemplated, as the best means of developing the natural capabilities of an undulatory surface, and of displaying the geological formation of the substrata.
Workman's draining-level — particularly designed for labourers incapable of using the spirit-level, but who are familiar with the properties of the plumb-bob.
Improved workman's level, similar in principle, but capable of greater facility of adjustment, with or without the spirit-level.