"A cylindrical boiler was tested and withstood a steam pressure of 300 pounds (300 psi or 2,068 kPa) without injury." " When the valve was suddenly opened at a pressure of 235 pounds [ the boiler gave way, the iron being twisted and torn into fragments and thrown in all directions. The reason for this was that the sudden rush of steam from the boiler into the discharge pipe reduced the pressure in the boiler very rapidly. This reduction of pressure caused the sudden formation of a great quantity of steam within the water, and the heavy mass of water being thrown with great violence toward the opening whence the steam was being withdrawn, struck the portions of the boiler near that opening and caused the fracture."