Chemistry: Volume of gas?

use a gasometric system where a beaker is filled with water and a graduated cylinder is filled with water, turned upside down and submerged into the beaker. The grad, cylinder needs to be held up and clamped to a ring stand. Then a rubber tubing is placed in the beaker of water and up into the submerged, suspended grad cylinder. the other end of the rubber tubing is then placed in a stopper with a hole. This stopper will cover a flask in which a reaction takes place releasing gas. The gas will then travel through the rubber tubing and up into the grad cylinder displacing the water in there. This will allow one to measure the amount of gas produced by reading the distance the water moved.