Page:The Mystery of the Sea.djvu/309

Rh angle of the cavern where it ran up to a sort of point. I scrambled up beside her, and making use of my greater height, took the torch and keeping it away at arm's length put my hand into the narrowing angle. I had a sort of secret hope that there might be some long crack or rift which, though it might be impossible for our bodies, might still give us air. Any such half-formed hope was soon shattered; the angle of the cave was in the solid rock, and there was no fissure or even crack beyond.

As there was no clue to the level reached by the tide, I tried back on the possibility of gauging it by measuring from low water, so far as my memory of the tides might serve. Judging by the depth of the water, so far as I had gone, the fall of the floor level must here have been some three feet. The floor level of the cave was almost that of low water, except where it dipped under the overhanging roof, or where was the ascending grade up to the pool in which the treasure boxes lay. As here on the border of the North Sea, with no estuary to increase tidage, the normal rise of the tide is between eleven and twelve feet, we had to account for another eight or nine feet for the rise of the tide. The ledge was about a foot above the surface of the water. If my calculations were correct there was head room and breathing space, for as I stood on the ledge the top of my head was still about two feet from the highest point of roof over us. I could not, however, be certain of my calculations, within a couple of feet. If, therefore, we could keep our place on the shelf of rock and endure the cold we might yet win through. The cold was a serious matter. At Cruden where the full sweep of the icy current from the North Sea runs in shore, the water is grievously cold, even in the hottest summer time. Already we were feeling the effects of our wet clothes, even in this silent cavern where the heat seemed to be much more than out-