me all about it this evening."

"One minute, father!" I cried; and thereupon I ran to the house,
reappearing in a few seconds with his rubber boots, which I thrust into
the back of the buggy, and then, climbing in on one side while Joe
scrambled in on the other, I called out:

"Now, father, go ahead!"

"Where to?" he asked, laughing.

"Oh, I forgot," said I. "Up to our stone-quarry."

If we had expected my father to be surprised, we were not disappointed.
At first he rather demurred at going down our carefully prepared
ladders, not seeing sufficient reason, as he declared, to risk his neck;
but the moment we called his attention to the sound of water down below,
and he began to understand what the presence of the rubber boots meant,
he became as eager as either Joe or I had been.

In short, he went with us over the whole ground, even down to the pool;
and so interested was he in the matter that he quite forgot the flight
of time, until, having reascended the ladders and followed with us our
line on the surface down to the heap of stones with which we had marked
the thousand-foot point, he--and we, too--were recalled to our duties by
my mother, who, seeing us standing there talking, came to the back-door
of the kitchen and called to us to come in at once if we wanted any
supper.

Long was the discussion that ensued that evening as we sat around the
fire in the big stone fireplace; but long as it was, it ended as it had
begun with a remark made by my father.

"Well," said he, as he leaned back in his chair and crossed his
slippered feet before the fire, "it appears to come to this: instead of
discovering a way to drain 'the forty rods,' you have only provided us
with another insoluble problem to puzzle our heads over. There seems to
be no way that we can figure out--at present, anyhow--by which the water
can be brought to the surface, and consequently our only resource is,
apparently, to discover, if possible, where it first runs in under the
lava-bed, to come squirting out again down in that fissure--an almost
hopeless task, I fear."

"It does look pretty hopeless," Joe assented; "though we have found out
one thing, at least, which may be of service in our search, and that is
that the water runs between the lava and the sandstone. That fact should
be of some help to us, for it removes from the list of streams to be
examined all those whose beds lie below the sandstone."

"That's true enough," I agreed. "But,