April 20.--In the last three days I have made several expeditions to the Blue John Gap, and have even penetrated some short distance, but my bicycle lantern is so small and weak that I dare not trust myself very far. I shall do the thing more systematically. I have heard no sound at all, and could almost believe that I had been the victim of some hallucination suggested, perhaps, by Armitage's conversation. Of course, the whole idea is absurd, and yet I must confess that those bushes at the entrance of the cave do present an appearance as if some heavy creature had forced its way through them. I begin to be keenly interested. I have said nothing to the Miss Allertons, for they are quite superstitious enough already, but I have bought some candles, and mean to investigate for myself. I observed this morning that among the numerous tufts of sheep's wool which lay among the bushes near the cavern there was one which was smeared with blood. Of course, my reason tells me that if sheep wander into such rocky places they are likely to injure themselves, and yet somehow that splash of crimson gave me a sudden shock, and for a moment I found myself shrinking back in horror from the old Roman arch. A fetid breath seemed to ooze from the black depths into which I peered. Could it indeed be possible that some nameless thing, some dreadful presence, was lurking down yonder? I should have been incapable of such feelings in the days of my strength, but one grows more nervous and fanciful when one's health is shaken. For the moment I weakened in my resolution, and was ready to leave the secret of the old mine, if one exists, for ever unsolved. But tonight my interest has returned and my nerves grown more steady. Tomorrow I trust that I shall have gone more deeply into this matter. April 22.--Let me try and set down as accurately as I can my extraordinary experience of yesterday. I started in the afternoon, and made my way to the Blue John Gap. I confess that my misgivings returned as I gazed into its depths, and I wished that I had brought a companion to share my exploration. Finally, with a return of resolution, I lit my candle, pushed my way through the briars, and descended into the rocky shaft.