smudges with heavy smoke,
drifting over the orchards or the truck fields, if started early enough
in the evening may check a freeze."

"Why, sir?" asked Ross. "Smoke isn't hot."

"No, my boy. But you remember that I told you that the cold was caused
by the radiation of heat from the earth escaping into the air and
through it. If there's a steady layer of smoke, like a blanket, floating
across the land, the heat radiating from the earth will not have a
chance to escape to the upper air. It will stay in the lower layer of
the air and thus keep it from dropping to the killing temperatures of a
true freeze. That's what the Indians of the pueblos used to do."

In the mild winters and early springs of Issaquena County, there seemed
little reason for the boys of the League to trouble themselves with
frost warnings, but, at the Forecaster's urgency, the boys kept wide
awake for it. It happened, though, that the lads had talked so much
about their frost protection plans that several of the farmers decided
to get some oil-burning fire-pots for use that spring, in the event of a
freeze. Jed Tighe, however, one of the few people of the neighborhood
who had shown but a perfunctory interest in the League, laughed to scorn
the idea of buying the fire-pots, as Fred had suggested in a recent
issue of the _Review_. Even Jed Tighe read the little sheet every week,
in spite of his alleged scornfulness.

One afternoon, when Ross was over at the club-house, where he spent so
much of his spare time, Anton pointed out that the conditions were ripe
for a killing frost.

"The hottest to-day was sixty-two degrees," he said, "and you remember
Mr. Levin told us that one wasn't ever safe unless the maximum was
sixty-four. There's not a cloud in the sky anywhere and there's
practically no wind, and what there is, Tom told me over Bob's wireless,
is from the northwest, and that's the worst quarter. I was just going to
take the dew-point when you came in."

"Let's do it now, Anton," said Ross. "Got the cup?"

For answer the crippled lad took down from the shelf a small tin mug. It
was already bright and shining, but he polished it until it looked like
silver.

"I've got the jug of ice-water ready," he said.

Pouring some tap water into the cup, and filling it about one third
full, he began to stir it round and round with a thermometer. The
mercury in the tube quickly dropped, until it read 50 deg., showing the
temperature of the water.

"