Page:Transactions of the Natural History Society of Northumberland, Durham, and Newcastle-upon-Tyne 1838 Vol.2.djvu/324

284 These, and the other sections introduced in this plan, suffice to show that whenever it is desirable to combine several geological Sections in one drawing, this mode of projection affords the means of doing so. The escarpment and surface of rocks may be represented so as to show the connection of the several beds or strata of which they are composed. Outlines of the surface of a mountainous district may be represented in various directions, and coloured so as to denote the basset of different strata. Isometrical Projections may be made either from given measurements or from ordinary plans and sections, by a process much more simple and easy than the rules of common perspective. It approaches more nearly than any other mode of drawing to the clearness of a model.

The collection of information respecting the strata and subterranean phenomena of the great mining fields of the north of England is an especial object of this Society, and is of great importance in a district so dependent as this is on subterranean sources of wealth. Next to the collection of such details, their arrangement in such a form as may be generally useful, claims attention; and, in many instances, the simple and comprehensive mode of Isometrical Projection may be employed with considerable effect, and present the details of geological structure, combined with the attractions of a picture.