64 
GREELY. 
This extension eastward of rainfall, originally dependent 
for its source on an arm. of the Pacific ocean, as far as western 
Texas, is a striking illustration of the fact, obvious with the 
precipitation over the temperate zone of the northern hemis¬ 
phere with its westerly wind circulation, that precipitation 
is deposited with greater facility to the eastward of rather 
than to the westward of its origin. 
The line of demarcation between the Trans-Mississippi 
type and that of the Gulf in eastern Texas and of the Trans- 
Pecos in western Texas cannot, in the nature of the case, be 
sharply and definitely drawn. In consequence, a very large 
part of the State, perhaps one-half, shares the combined 
characteristics of the three types whereby May and Septem¬ 
ber are months of maxima (primary and secondary) rainfall 
and January and July months of minima (primary and sec¬ 
ondary) precipitation. 
It is very fortunate for Texas that neither the Gulf nor 
the Trans-Pecos type of rainfall distribution obtains over 
the whole State, since autumnal maxima of precipitation 
are not usually favorable to agricultural interests unless 
supplemented by abundant rain in other seasons. Happily 
the coast has sufficient rain in all seasons, save in years of 
exceptional droughts, while over the central meridians the 
obtaining maxima of the late spring are usually marked 
by sufficiently copious rains to subserve the needs of agri¬ 
culturalists. 
It thus results that the extreme western portions of the 
State are the only regions where deficient rainfall and un¬ 
seasonable distribution make it regularly needful to resort 
to irrigation for successful farming. 
In conclusion, it is not strictly relevant to the subject, but 
it may be a matter of interest to some of the Society to 
point out the bearing which the Trans-Pecos type of rainfall 
has upon the late experiment made under the supervision of 
the Department of Agriculture for the purpose of producing 
rain by artificial means. These experiments were made, I 
believe, either in the Trans-Pecos region or adjacent thereto, 
