THE TEXAN MONSOONS. 
299 
The weather maps are now based on observations taken 
at 8 a. m. and 8 p. ni. of Eastern standard time. This is 
about 6 a. m. and 6 p. m. by Texas local time. An inspec¬ 
tion of the maps shows that the disturbances of the south¬ 
erly winds caused by cyclones and anti-cyclones are appre¬ 
ciably greater in the early morning than in the early 
evening. This is probably due to the fact that the temper¬ 
ature is at about its minimum at 6 a. in. in summer, and a 
wind due to differences in temperature of land and water 
would be weaker at that time than at 6 p. m.—a few hours 
after the daily maximum of temperature. 
To make a thorough investigation of the velocity of the 
southerly winds would require a collation of the records by 
hours and days for the winds from different directions. This 
is an arrangement of the data which is not usually made, 
and it has not as yet been made in the Weather Bureau. It 
would require a great deal of labor to make it. The record 
sheets of the registering anemometers show, on glancing 
through them and taking only the cases where the south¬ 
erly winds are fairly independent of cyclonic or anti-cyclonic 
action, that these winds often continue day and night, but 
with a decrease of velocity in the morning hours. As a 
typical case, the record at Abilene, which is far inland, for 
the dates August 13 to August 21, 1891, shows that the 
mean velocities for the south and southeast winds during 
this time were as follows: 
Wind Velocities at Abilene, Texas, August 13 to August 21, 1891. 
Honrs. 
1 
Miles 
per 
hour. 
Hours. 
Miles 
per 
hour. 
Hours. 
Miles 
per 
hour. 
Hours. 
Miles 
per 
hour. 
Midn.... 
9.7 
6 a. m. 
9.6 
Noon... 
11.8 
6 p. m. 
13.8 
la. m... 
9.1 
7 “.. 
8.1 
1 p. m. 
10.5 
7 
13.9 
2 “ ... 
9.3 
8 “.. 
9.7 
2 11 
12.2 
8 
11.0 
3 “ ... 
9.6 
9 
12.2 
3 “ !! 
12.7 
9 “.. 
10.1 
4 “ ... 
9.2 
10 
12.9 
4 “ .. 
13.5 
10 “.. 
10.6 
5 “ ... 
9.8 
11 “.. 
11.9 
5 “ .. 
12.6 
11 
10.4 
