il end of a 'high,' with a high barometric pressure--five
points above the low in Salt Lake City--with a cold temperature, and
with a wind blowing outwards from the 'high' or anti-cyclone. Is that
clear?"

"Clear as well water," the farmer declared.

"Now," said the Forecaster, "let us look at yesterday's map for eight
o'clock in the morning. Here, just over the Canadian border, right at
Medicine Hat--as though to make good the old proverb--is a vigorous
'high,' with a barometer of 30.50, with a temperature of 20 deg. below zero
and with the winds blowing outward from the centre. The 'low,' which the
day before yesterday was central over Salt Lake City, yesterday was
central over Oklahoma City. It has, therefore, traveled over five
hundred miles in the day. On all sides of the 'low' there is rain, and
you remember how it rained here, yesterday morning, early?"

"Indeed I do," said Jed Tighe. "I didn't get out on the land until
nearly eleven o'clock."

"Now what was the temperature here yesterday morning, Anton?" the
Forecaster queried.

"Forty-six degrees," answered Anton promptly, for he had been expecting
the question.

"Ten degrees warmer, you see, Mr. Tighe, as the 'low' came nearer. And
what was the wind, Tom?"

"South-south-east," the lad answered, his note-book in hand.

"Showing," the Forecaster explained, "that during the twenty-four hours,
Issaquena County had lost the effect of the 'high,' which has
disappeared from the map, and was fully in the grip of the oncoming
'low.' Now, if you look at the map, Mr. Tighe, you'll see that the
isobar for this region shows a barometer pressure of 29.50, a terrific
drop of four points in twenty-four hours. No wonder it rained!"

The farmer bent over the map, his eyes glued on the lines which suddenly
seemed to spring into life before him.

"Down over the country comes this 'low,' at the rate of five hundred
miles a day, with rain and moist winds accompanying it, and sharp on its
heels, racing from the north, comes the cold 'high' which we have just
seen forming at Medicine Hat. The cold wave is fully organized and is on
its way."

He laid the third map on the table.

"Here is the situation at eight o'clock this morning," he said. "The
'low' or storm, has swung at right angles, following the preferred Ohio
and St. Lawrence Valley Route. It left Toledo early this morning and at
eight o'clock was raging over the Great Lakes, with its centre north of
Buffalo. I