A discovery was made on the return trip.  The horses had been brought along to ride home on, but in testing the sleet on the divide, the sun had softened the crust until it would break under the weight of either of the boys.  By walking well outside the trail, the sleet crushed to the extent of five or six feet, and by leading their horses, the pathway was easily doubled in width.  Often the crust cracked to an unknown distance, easing from the frost, which the boys accepted as the forerunner of thawing weather.

“We’ll put out poison to-night,” said Dell.  “It will hardly freeze a shoal, and I’ve found one below the corral.”

“I’m just as anxious as you to put out the bait,” replied Joel, “but we must take no chances of making our work sure.  The moment the cattle quit drinking, the water holes freeze over.  This is regular old Billy Winter.”

“I’ll show you the ripple and leave it to you,” argued the younger boy.  “Under this crust of sleet and snow, running water won’t freeze.”

“Along about sunset we can tell more about the weather for to-night,” said Joel, with a finality which disposed of the matter for the present.

On reaching the corral, the older boy was delighted with the splendid trail broken out, but Dell rode in search of a known shallow in the creek.  An old wood road crossed on the pebbly shoal, and forcing his horse to feel his way through the softened crust, a riplet was unearthed as it purled from under an earthen bank.

“Here’s your running water,” shouted Dell, dropping the reins and allowing Dog-toe to drink.  “Here you are—­come and see for yourself.”

Joel was delighted with Dell’s discovery.  In fact, the water, after emerging from under a concave bank, within a few feet passed under another arch, its motion preventing freezing.

“Don’t dismount,” said Joel, emphasizing caution, “but let the horses break a narrow trail across the water.  This is perfect.  We’ll build another fire to-night, and lay a half dozen baits around this open water.”

The pelt of the dead wolf was taken, when the boys cantered in home.  Time was barely allowed to bolt a meal, when the loading of the wooden troughs was begun.  Every caution urged was observed; the basins were handled with a hay fork, sledded to the scene, and dropped from horseback, untouched by a human hand.  To make sure that the poison would be found, a rope was noosed to the carcass and a scented trace was made from every quarter, converging at the open water and tempting baits.

“There,” said Dell, on completing the spoor, “if that doesn’t get a wolf, then our work wasn’t cunningly done.”

“Now, don’t forget to throw that carcass back on the ledge, under the comb,” added Joel.  “Wolves have a reputation of licking each other’s bones, and we must deny them everything eatable except poisoned suet.”