, allows the gas to be collected in a graduated tube filled with water. The tube,
, and its insulator are plunged into a bath of liquid hydrogen,
'. Under these conditions no gas is produced in the tube
. When a bottle containing 0.7 gram of radium bromide is placed in the hydrogen in
, there is a continuous liberation of hydrogen gas, and 73 cc. of the gas are collected per minute. (The radium bromide had been made only ten days before.)