About two hours after midnight
It was a strange and a weird journey , but we went on hour after hour , and nothing molested us . About midnight we halted to let the beasts graze for half an hour in a grassy vale , while we did what Tom called the same ; our pasture being cake , and our drink spirit and water . Refreshed by our short halt , we again journeyed , and from time to time , after giving Tom the bridle of my mule , I stayed back to listen and try to discover whether we were followed ; but , save the cry of some beast , there was nothing to be heard . About two hours after midnight we struck the little stream , and soon after were well in the ravine , when , for the purpose of exercising greater caution , and , as Tom said , running the risk of being stung , we each took the bridle of our mule over one arm and went down on all fours , crawling forward ; and so slow was our progress that , were we watched and a glimpse of us obtained , I felt certain that we must be taken for a little herd slowly grazing towards the mouth of the great cavern . We reached the rocky pass at last , and then , muffling the feet of the mules with the coffee-bags , we took them cautiously on -- the intelligent beasts clambering carefully and with hardly a sound -- when we led them right in for some distance , gave them the maize we had brought , and then sat down in the darkness listening to their crunching of the grain and the loud cries of the guacharo birds as they flew in and out , fortifying ourselves the while with a hearty meal -- Tom foregoing his pipe for reasons of cautious tendency . According to my calculations the day would break in about an hour 's time ; and during that hour , but always on the alert , we stretched ourselves upon the sand to rest , listening to every sound ; for there was the possibility , we knew , of there being enemies , biped or quadruped , within a few yards of where we rested . Towards daybreak it turned intensely cold -- colder than I could have imagined possible in a tropic land ; but we were prepared to bear cold as well as danger , for a fire would , of course , have been inviting observation .