Isometric block diagrams in mining geology

In the past five years members of the Geological Survey have gained experience in making isometric block diagrams of mines and mining districts as well as of surface features. This paper presents nothing new, but aims to assemble scattered information on a much neglected method of geological illustration. Plotting mine workings on isometric paper is the usual method but is extremely time-consuming. For most purposes the use of some form of isometric pantograph greatly lessens the labor of constructing the diagram. The devices of Dufour, Wentworth, Wilson, and Van der Hoop are described