coastline, the currents of the ocean and a thousand other factors. Each
of these the Weather Man has to study when he makes a forecast, but, in
the United States, his work is aided by the fact that weather always
travels eastward and that the storm follows regular tracks, sharply
outlined, like Indian trails across the country."

"Roads in the air?" queried Fred.

"Yes, my boy," the Forecaster answered, "regular roads in the air. There
used to be an old saying: 'American weather is made at Medicine Hat.' In
a sense this was true, for about sixty per cent of the storm
areas--'lows' or region of low barometric pressure--come from the
Canadian Northwest. The St. Lawrence Valley is the outlet for our
storms. You know the saying about the St. Lawrence, don't you?"

"No, tell us, Mr. Levin," begged Fred, always eager for some weather
saying which he could put into the _Review_.

"Up there," the Forecaster rejoined, "they say that when a stranger
complains about the weather, a native will reply, 'Don't mind this,
we'll have another sample along in about five minutes.' And, sure
enough, they do. The St. Lawrence Valley is a magnet for weather changes
and has, perhaps, more storms than any other valley in the world."

"You spoke of the 'roads in the air,' sir," put in Ross, "how many are
there?"

"Five regular trails," the Forecaster answered. "The northernmost one
begins at the Canadian Northwest, runs along the International Boundary,
crosses the Lake region and disappears up the St. Lawrence Valley. The
second starts at the same point in the Canadian Northwest, travels
southeast to the lower Mississippi Valley--a little north of where we
are now, boys--curves up to the Ohio Valley and also escapes by the St.
Lawrence route.

"A third storm track strikes into the Pacific Coast a little north of
San Francisco and runs east and a little south until it joins the Ohio
Valley and St. Lawrence track. A fourth develops in the southwestern
states and runs along Texas and the gulf states to the Florida coast,
where it curves northward along the Atlantic coast, though a few storms
take a sharp turn in the Mississippi Valley and go Ohiowards. The fifth
storm track is that of the West Indian hurricanes, which whirl around
the West Indies and enter the United States south of Cape Hatteras or
from the Gulf of Mexico and pass north or northeastward. A few of these
hurricanes--like the famous Galveston type--sweep westwards a long way