Page:Lowell Hydraulic Experiments, 4th edition.djvu/42



50. Previously to the commencement of the experiments, the apparatus for measuring the useful effect was carefully adjusted. The bell crank was balanced when there were no weights in the scale. For this purpose the link M, figure 3, plate IV., was removed, and the chamber of the hydraulic regulator filled with water; — weights were then applied to the top of the bell crank, near the end to which the hydraulic regulator was attached, until the whole was in equilibrium; — the final adjustment was made, by placing a weight of about two pounds at the extremity of one of the horizontal arms of the bell crank, — the arm was retained horizontally until a signal was given, when it was left at liberty to descend, and the time occupied in descending a certain distance was noted; — the weight was then removed to the extremity of the other arm, and the same process repeated. The balance weights were altered until the times of descent