E;*+ - Geological Curators

DISCOVERY OF WORKING DRAWINGS FOR THE SOPWITH MODELS OF 1841
Abstract
AT THE HANCOCK MUSEUM
Working drawings have been discovered for aynique series of three-inch
Sopwith hand-models of geological structures prekent in the Newcastle coalfield
and the Northern Pennine lead mines. The drawings are related to the set of
twelve geological models published in 1841 by Sopwith. Their historical
importance is briefly assessed.
1. INTRODUCTION
For a large part of his professional life, Thomas Sopwith was involved in
practical aspects of geology in the Newcastle coalfield and in the lead mines of
the Northern Pennines. An understanding of the relatively simple geological
structures, gently inclined strata offset by normal faults, of both regions was
of very practical importance in the estimation of coal reserves, and in predicting
the continuation of a coal seam and a mineral lode displaced by faulting. It
must be remembered that the coalfield, and large parts of the lead mining areas
were obscured at the surface by spreads of glacial drift. The practical miner
was confronted with problems of prediction in three-dimensions, often on the
basis of plans of mine workings, which presented very difficult conceptual
problems. A geological map or, at a larger scale, a geological plan of mine
workings presents a two-dimensional view of a three-dimensional world, the
real world of mining and understanding geological structures from a practical
viewpoint.
Contemporaries, and near contemporaries of Sopwith had begun to grasp
the nettle: Forster (1809, 1821) had presented two-dimensional sections of strata
in the orefield, and Buddle (1831) had published two-dimensional traverses of
the coalfields. But the problem was three-dimensional, demanding models rather
than plans and elevations. Sopwith developed isometric projections as a means
of visualisation in three-dimensions, but almost concurrently began to make
three-dimensional models of entire coalfields, and hand-models illustrative of
particular problems. In this he was following in the tradition of Farey (1811)
who 'published an instructive series of coloured diagrams (block-diagrams,
see Rudwick, 1976) to explain the natures of faults or disl.ocations, and tilts
of the strata, also of subsequent denudation' - diagrams which may be regarded
as the precursors of the famous models afterwards constructed by Sopwith
(Woodward, 1911, p.55).
Engineers today concerned with interpreting and understanding the behaviour
of geological structures in three-dimensions on the basis of limited site
investigation data, have the same conceptual problems as the engineer in the
early part of the nineteenth century. Today techniques of engineering
geological mapping, or the representation of geological structures for the
engineer, make use of every expedient to improve representation and with it
understanding. Plans, elevations, cross-sections, fence-diagrams, isometric
projections and three-dimensional models are all used as visual, conceptual aids.
To a very large extent Sopwith initiated this approach with his insistence on the
practical limitations of the conventional engineering plan'and elevation, and
replaced these first with isometric projections and finally with fully three-
dimensioned scale models. His hand-models of basic geological structures,
discussed here, mark an important step in the provision of visual aids directed
to the clarification and understanding of general geological principles. As
such, Sopwith must be regarded as a pioneer in representing geological structures