Precautions against external Dangers to Workings Precautions against external Dangers to Workings 75—77. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Precautions against external Dangers to Workings