But the task of digging the trenches was not as arduous as it had appeared.  The sand was soft and yielding, and the shovels made rapid work with it.  Soon a fairly deep trench was dug round each of the temporary shelters.

By the time the lanterns had been filled, and Zeb had cut a goodly stack of mesquite wood, everything was ready to begin preparations for supper.

“We’ll have a blow-out to-night,” said Zeb.  “Canned salmon, beans, crackers, cheese and canned fruit, but don’t expect to get that right along.  I’ve lived on beans and bacon for six months in this very neck of the woods, and thought myself lucky to get that.”

“Hullo!” came a cry from the direction of the river.

“There’s Dick!” exclaimed both boys, and then as the young reporter came into sight, “What luck, Dick?”

“What do you know about this?” and Dick held up a fine string of glittering fish.  There were catfish, perch and two eels.

“Good; we won’t go hungry,” said Zeb.  “Nothing better than fried eels and catfish.”

He greased the frying pan with a strip of bacon rind and then skinned the scaleless catfish and eels as if he had been doing nothing else all his life.  Soon the savory odors of the frying with crisp slices of bacon, and the aroma of coffee, filled the camp.

The boys were so busy setting out the tin cups and plates that it was not till Zeb beat on a tin basin with a spoon to announce that the evening meal was ready that anyone noticed that the professor was missing.  Night was closing in and the sky was overcast.

The boys began to worry.  They set up a loud shout.

“Pro-fess-or!  Oh, pro-fess-or!”

The little gulch rang with it.  But no answer came.

“Now what in the world has happened to him?” frowned Jack.  “We must go and find him at once.  He must have——­”

[Illustration:  Soon the savory odors of the frying with crisp slices of bacon, ...filled the air—­Page 208.]

The sentence was never completed.  At that instant Zeb set up a shout, and a ton of earth and rocks, more or less, came hurtling down the steep bank into the camp.  The stones and dirt were mingled with mesquite bushes and in the midst of the landslide was a figure that they made out to be the professor.

Luckily, the avalanche had missed the camp-fire and the supper table, and when they had extricated the professor, and brushed him off, the boys learned that he had almost missed his way, and being shortsighted, in the dark had walked right over the edge of the steepest part of the arroyo instead of by a sloping path up above.

However, nothing was injured about him but his feelings, and since his bag of specimens was intact, the man of science, after a few minutes, was able to sit down and eat with as good an appetite as any of them.

Zeb proved himself a good weather profit.  About midnight it started raining, and such rain as the boys had never seen.  It was not rain.  It was sheets of water.  Even the waterproof tents began to leak, and the fact that the trenches had been dug did not serve to keep the floors dry, for the hard, sun-baked earth did not absorb the moisture, and the downpour speedily spread half an inch or more of water over the ground.