Excerpt from The Journal of the Franklin Institute, Vol. 118: Devoted to Science and the Mechanic Arts; Nos. 703 708; July to December, 1884 As the Perkiomen division is the most extensive, my instructions were to make a beginning on that side, and accordingly explorations and surveys of all those streams were immediately begun in order to establish gauging points. It was proposed at first to use as far as possible current meters for gauging, but investigation showed that little could be done to advan tage with those instruments under the ordinary conditions of the sum mer flow of the streams. These natural channels are very rough and of considerable width, showing everywhere the marks of the high flows of the winter and spring months, and the inclination of their beds are, as a rule, considerable, the streams forming, in most cases, _a constant succession of mill-ponds, with but short intervals between each dam and the head of the succeeding pond below. Besides, the extreme shallowness of all the streams in their normal summer condition ren dered the use of the current meter impossible at points where there was a perceptible current. Accordingly it was decided to build a number of low weirs or dams, and to measure the flow passing them. This method offered the advantage that the manner of observation is simple, taking but little time, and affording opportunities for continuous measurements when ever desired. The weirs were intended to gauge the ordinary summer or low flows, and the meters were to be used whenever the streams were too high to allow the weirs to act as such. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.