56 
GREELY. 
practically prairie country such as is most of Texas, can be 
formed a fairly accurate judgment of the precipitation of the 
intervening regions. 
The average annual rainfall of Texas varies from about 
52 inches in the extreme eastern counties to about 10 inches 
in El Paso county. The largest annual rainfall, as deter¬ 
mined from records of considerable length, are Clarksville, 
12 years, 57.13 inches; Galveston, 21 years, 52.33 inches; 
the smallest, El Paso, 22 years of miscellaneous records, 9.37, 
and Fort Stockton, 16 years, 15.94 inches. In connection 
with the El Paso rainfall it should be noted that for twelve 
years ending with 1890 the annual mean rainfall, as deter¬ 
mined from Signal Corps records, is 10.54 inches. This 
latter mean is doubtless the more reliable. 
It needs but casual examination of the available data to 
decide on or to verify the opinion that the average yearly 
precipitation decreases from east or southeast to west and 
northwest. In other words, the rainfall diminishes in quite 
regular proportion as the distances increase from the primary 
source of rain, which for the greater part of Texas is the 
Gulf of Mexico. Such decrease in the yearly precipitation 
also coincides, as a general rule, with increasing elevation— 
an incident and not a cause. 
It has been suggested that the rainfall over the Llano 
Estacado is more copious than over the country lying imme¬ 
diately to the eastward, but all accessible data indicate the 
incorrectness of this theory or supposition, except where the 
Trans-Pecos type of rainfall overlaps that of central Texas. 
Doubtless in this case, as in other sections of the United 
States, the amount of local rainfall is somewhat affected by 
the configuration of the adjacent country. However, save 
in the mountainous regions of extreme western Texas, it is 
not probable that the rise in elevation is sufficiently rapid to 
compensate by its diminished temperature for the advantages 
arising from the increased distance from the Gulf of Mexico 
or the Gulf of California, according to the regularly varying 
or to accidental meteorological conditions. In any event, 
