Chicago Paper - An Improved Hanging Compass

In working brown iron-ore mines on the system employed at Longdale, namely, stoping from the top down, the usual procedure is to drive a succession of upraises from the lowest adit to the highest, or to the top of the deposit, as the case may be. These up-raises are usually driven 120 feet apart., along the strike of the vein,. As the work goes on, they are connected by levels, 10 feet spa* (vertically), and then serve as chutes. A transit is useless in surveying these chutes, and the writer has for several years made use of a hanging compass. The method of using this instrument, described in a former paper (Trans., xx.,.105), embracing as it does the use of a cord and several strips. of wood,