OSMOSIS APPARATUS SET (LSE) The popular thistle tube form for illustrating the principles of osmosis. Consists of a double thistle tube with a porous membrane attached to the lower end. The tube is held upright with the membrane covered end in the jar. When sugar solution is added to the top of the tube, the liquid level gradually rises. Included are a round battery jar, a 16" long glass thistle tube, membrane, tube support. Qty :