CHARLE’S LAW APPARATUS a bulb and tap at the upper end of one limb and other limb open. From the bottom of the ‘U’ is an outlet tube which passes through a bung and terminates in a tap. The stem below the bulb is graduated 3 x 0.1 ml, an inlet tube with Mohr clip also passes through the bung. The glass water jacket encloses the U tube. All glass parts made of borosilicate glass required only 20 ml mercury. Without mercury