A Triangulation Survey: For a Tunnel at Niagara

Abstract

The article discusses a triangulation survey required to create a tunnel "a mile long and pass under the heart of the city, a triangulation survey for it must needs be made, of a sufficiently accurate character as to enable the centre lines to be located and produced from each of the three shafts. In a paper of this kind, it is not intended to describe in detail this proposed tunnel; the preliminary survey being the object. A few points, however, must be introduced, so as to convey a general idea of the nature of the work."