BULLETIN 918, U. S. DEPARTMENT OF AGRICULTURE. 
JAN. FEB. MAR. APR. MAY JUNE JULY AU6. SEPT. OCT. NOV. DEC 
The Laguna district is an irregularly shaped valley of about 2,000 
square miles, almost completely surrounded by mountains. It is 
situated about 250 miles south of the Bio Grande, on the boundary 
line of the States of Durango and Coahuila, Mexico. It derives its 
name from the fact that it was formerly a lake (laguna) serving as 
an outlet of the Rio Nazas. As recently as 1837 a part of the Tla- 
hualilo property was 
under water and at 
present there are con- 
siderable areas near 
San Pedro, Coahuila, 
which are filled with 
water when the river 
is at a flood stage. 
The soil is a deep al- 
luvial deposit, very 
rich, and well adapted 
to the culture of 
cotton. 
CLIMATIC CONDITIONS. 
Torreon, the prin- 
cipal city of the Lagu- 
na, has an elevation 
of about 4,000 feet. 
Generally speaking, 
this section of the 
country receives an 
average of 6 to 8 in- 
ches rainfall annually, 
but in 1919 the pre- 
cipitation was very 
close to 15 inches. 
In the months of 
May, June, July, and 
August temperatures 
range from 95°to 100° 
F. during the day 
In the winter months 
no 
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1916 
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1919 
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Fig. 1. 
Average mean temperature for 1918 and 1919 at 
Ciudad Lerdo, Durango. Mexico. 
down to about 64° (average) at night. 
of December, January, and February the thermometer registers from 
69° (average maximum) to as low as 24° F. 
Figure 1 gives a graphic record of the thermometer readings taken 
at the station in Ciudad Lerdo, Durango. 
It must be kept in mind that the above charts represent the aver- 
age of the daily readings for each month and not the extremes which 
