302 
HARRINGTON. 
winds. They cause a fall in temperature, but this is often 
slight. Occasionally the cyclonic or anti-cyclonic condi¬ 
tions are especially favorable to the setting up of the north 
winds. When this happens, and especially when both com¬ 
bine to the same effect, the north winds may come down the 
plains with great velocity, with a sharply defined head of 
cloud like a battering ram, replacing warm and stagnant air 
and causing a sharp and great fall of temperature. These 
are the well-known Texas “ northers.” The “northers” are 
thus exaggerated cases of the prevailing north winds of 
winter on the southern part of the plains. They may also 
occur during the spring and autumn, and are then more 
noticeable to the residents because the chill they bring is more 
appreciable, and because a wind from the north is then less 
usual. When the conditions under which they are formed 
are especially favorable, they push their way far southward. 
They give tempestuous weather over the western part of the 
Gulf of Mexico. They even sometimes bring frost and snow 
on the high-land coffee plantations of Gautemala and Hon¬ 
duras, and, crossing the peninsula of Tehuantepec, they are 
sometimes encountered by ships far toward the equator on 
the Pacific ocean. 
The conditions especially favorable to the formation of 
“northers” fall easily under two types. The first, or essen¬ 
tially cyclonic type, was recognized by Professor Ferrel. It 
is where a warm winter cyclone is closely followed by a mass 
of cold air. The pressure in the rear of the cyclone rises 
sharply, the heavy air behind, coming directly from the 
north, presses closely on it, and a sharp fall of temperature 
with northerly winds results. This is most common with 
winter cyclones originating in or crossing the western Gulf or 
southern Texas. The warm vapor laden air is suddenly dis¬ 
placed by the cold, dry, piercing air from the north, and the 
very contrasts between the two unlock energies which pro¬ 
mote the latter. Good specimens of this type can be seen on 
the weather maps for the forenoon of December 3, 1890; also 
the afternoon of December 7 and morning of December 8; 
