 The ring used in the initial experiment was made of one inch brass tubing bent into a circle eighteen inches in diameter, where the windows were placed the tube was constricted to a diameter of about three eights of an inch.Compton used small droplets of coal oil mixed in the water to measure the drift velocity under a microscope.Assume the diameter of the glass tube is much smaller than the diameter of the ring, and formula_1 is the radius of the ring, formula_2 is the Earth rotation rate and formula_3 is the latitude.