Board of Water Supply. Conduit and Reservoir Division. Narrows Siphon 1. Experiment 124, one of many experiments made to test the flexible jointed pipe. This joint was laid as the first flexible joint on Brooklyn shore. The apparatus for test deflection of joint is shown lashed to the joint. At forward end is hydraulic cylinder or jack working under 900 pounds to 1500 pounds per square inch. Two high pressure copper tubes connecting cylinder with pump are seen running from cylinder, one on each side of pipe. The hose running into the pipe is connected to the testing bulkheads spanning joint. September 2, 1914.