was
finally lit.

By this they found that Grip was the bearer of another note, and in
addition a packet, which upon being opened was found to contain a card
and a pencil.

The note was very brief, stating tersely that efforts were being made to
enlarge the way through which the dog had come up, and asking for
information regarding their state.

This was furnished as well as the circumstances would allow, Joe holding
the light, while, after placing the card on the smoothest place he could
find, Gwyn wrote the answer--the principal point he emphasised being
that they were safe so far; but the water was rising, and they had
nearly come to the end of their candles.

But even as he wrote there was a cheering sound heard through the
whistling of the wind--a sharp, clear clink as of hammer and chisel upon
stone.

"Hark! do you hear?" cried Joe, wildly; "they are coming down to us. Oh
work, work hard, before the water rises."

He shouted this in a wildly frantic way, and then watched eagerly while
Gwyn tied the card in a handkerchief and secured it to the dog's collar,
Grip going off directly, as if he quite understood the business now.

This done, Joe and Hardock lay down close to the orifice and listened to
the clinking of the hammers, trying the while to imagine what kind of
passage existed beyond the wedge-like block of stone, and calculating
how long it would be before they were rescued. But that was all
imagination, too, for there was nothing to base their calculations upon.

Meanwhile Gwyn was more matter-of-fact; for he took the lanthorn and
descended to where the water had risen, and there, clinging with one
hand, he held the light down, to gaze with a feeling of awe at the
bubbling surface, which was in a violent state of agitation, looking as
if it were boiling. Every now and then it was heaved up and then fell
back with a splash.

Gwyn's object in descending the sharp slope had been to make a mark upon
the rock with his knife just at the level of the water, and then try and
scratch other marks at about a foot apart, so as to descend again and
see how much higher the water had risen.

But this seemed to be impossible, for the level was always changing, the
water running up several feet at times and then descending, playing up
and down evidently as the pressure of the confined air increased or
sank.

Still he made some marks, and then returned to the others to join them
in listening.

But this prov