eight o'clock in the evening
Letter on the way . `` YOUR FATHER . '' Mr. Bradlaugh also gave a long whistle as he sank back in his chair thoughtfully and with the message in his hand . It was eight o'clock in the evening when Merry , Clancy , and Ballard reached the mine and went hunting for the office of Pardo , the superintendent . The surface activities of a big gold mine , in full operation at night , are as weird as they are interesting . The boys were deeply impressed as they looked down into the valley where the mining , milling , and cyaniding were going on . The stamp mill , where the ore was pounded to powder and robbed of its gold , was a huge , ramshackle structure .