ther and son took their picks； their sticks； and their lamps。 They went about searching； sounding the rock with a sharp blow； listening if it would return a favor…able sound。 So long as the soundings had not been pushed to the granite of the primary formation； the Fords were agreed that the search； unsuccessful to…day； might succeed to…morrow； and that it ought to be resumed。 They spent their whole life in endeavoring to bring Aberfoyle back to its former prosperity。 If the father died before the hour of success； the son was to go on with the task alone。
It was during these excursions that Harry was more particularly struck by certain phenomena； which he vainly sought to explain。 Several times； while walking along some narrow cross…alley； he seemed to hear sounds similar to those which would be produced by violent blows of a pickax against the wall。
Harry hastened to seek the cause of this mysterious work。 The tunnel was empty。 The light from the young miner's
lamp； thrown on the wall； revealed no trace of any recent work with pick or crowbar。 Harry would then ask himself if it was not the effect of some acoustic illusion； or some strange and fantastic echo。 At other times； on suddenly throwing a bright light into a suspicious…looking cleft in the rock； he thought he saw a shadow。 He rushed forward。 Nothing； and there was no opening to permit a human being to evade his pursuit！
Twice in one month； Harry； whilst visiting the west end of the