Velocity studies in a vertical pipe flowing full

"The purpose of this investigation is to install a hard drawn copper pipe approximately 1/2 inch in diameter, and approximately 35 feet long in a vertical position. The copper pipe is to have pressure takeoff points at various distances along the length of the pipe. The purpose of these takeoffs is to measure the pressure of the water at the point of takeoff in the pipe. The water is to be forced into the pipe, assisted by gravity, thereby causing a pressure of some measurable quanity [sic] greater than absolute zero pressure. The discharge was to be by volumetric measurement, as the pipe was flowing full, through the atmosphere into the weighing tank. The object of this investigation is, to study the type of flow in a vertical pipe flowing full where gravity assists the line pressure. The conditions existing within a vertical pipe under free fall are at present unknown. The effort of this study is to shed some light on this unknown subject"--Introduction, page 5.