' 
50 LANDS UF THE ARID REGION OF THE UNITED STATES. 
DISTRIBUTION OF RAIN THROUGH THE YEAR. 
In a general way the limit of agriculture without irrigation, or ‘dry 
farming”, is indicated by the curve of 20 inches rainfall, and where the 
rainfall is equally distributed through the year this limitation is without 
exception. But in certain districts the rainfall is concentrated in certain 
months so as to produce a “rainy season”, and wherever the temperature 
of the rainy season is adapted to the raising of crops it is found that “dry 
farming” can be carried on with less than 20 inches of annual rain. There 
are two such districts upon the borders of the Arid Region, and within its 
limits there may be a third. ks 
First District—Along the eastern border of the Arid Region a contrast 
has been observed between the results obtained at the north and at the 
south. In Texas 20 inches of rain are not sufficient for agriculture, while 
in Dakota and Minnesota a less amount is sufficient. The explanation is 
clearly developed by a comparison-of the tables of rainfall with reference 
to the distribution of rain in different seasons. 
TaBLE V.—Precipitation of Texas. 
b =S | 
| - | Mean precipitation, in inches. 5 
- | © aioe a = ce 
Station. ates = a3 . FA FI 2 = 
a z iS a 2 = a 5 ¥ 
4 a | DR | A 4 E A cs 
—— — — —— - —— ————— —| 
| I, On sea SOL ekaet. | | 
| Austin Stig SSeS So RE OE oonosceescaapnacss 3017 | 97 44 650 8. 61 7.94 | 10.74 6. 23 
| Camp Verde 30 00, 99 10 1, 400 6.11 9. 81 8.30) 5.05 
| Fort Relknap eres saat see cee ee ae ees eee eas | 33 08] 98 46 1, 600 6. 41 9. 44 8. 34 3. 86 
| Fort Bliss (El Paso) .........----------+--+--- | 3147] 106 30 | 3,830| 0.43] 3.49] 3.38] 1.23 | 
| Fort Brown --| 255 97 37 50 3.18 7. 64 13, 02 4, 04 
RoniG@hadbournotea ss: sees aaa ene anaes | 31 58 | 100 15 | 2,020 5.77 | 6.53 7. 06 3. 52 
Worti@larichsaewceceee ase se aes tee voce cease secs 29 17 | 100 25 1, 000 4.14 7.57 6.55 4. 35 | 
Fort; Davis.----.---.. 30 40 | 104 07 4, 700 1. 84 8. 76 4.72; 1.80 | 
Hort: Duncans -=-.== 28 39 | 100 30 1, 460 3.56| 8.60 6. 54 2. 63 | 
Hort Grifiin =-------2-- | 3254] 9914 |........ 4.95 | 6. 25 6.14 4.17 
|) INQ rE GVH season sen Roo ee SSoaSbor rota. Bosh bSodce 2910 | 99 50 845 5. 38 9. 67 6. 88 3.53 | 
PG CbPM AR OMe eee ee eee eee - | 8040) 9915 | 1,200 6. 36 10. 44 8. 22 3. 96 
Fort MeIntosh......-.-. | 2735] 9948 | g06| 3.22] 656] 5.38| 295] 17.5 | 
RorteMiCkavevte seprisn ster merterioa = esa 30 48 | 100 08 2, 060 5. 21 6.71 7.81 4,22 23. 95 9 7 | 
Helorhis too kbomeeceerer =o ae se 30 20 | 102 30 | 4, 950 1. 24 5. 66 3.31 | 1.29 11.50 5 8 | 
(Galveston=--->t6. -\-~.--|- 29 18 94 47 30 13.15 14. 90 16.83 | 12.19 57. 07 (iy) a 
| Gilmer (near) | 32 40| 94 59 950 | 13.36) 9.93] 11.77] 10.93] 45.99] 7 9| 
IMG AON Cee aaa seas seaseac Re anabebr oct 2942) 9815 720 7. 60 6. 90 8. 83 4.25 27. 58 5 1 | 
Ringgold Barracks | 2623] 99 00 521 3.71 | 7. 00 6. 34 2.58 | 19.60} 14 2 
SaneAnN Oni mee sec meas ae ne me cere } 2925] 98 25 600 6.77 8.91 9. 30 | 6.32} 31.30 | 10 2] 
Means tsaenacoeee: sees ose vives hacus a. Bee seeee coe seeeeeereeee 4. 62 | Bh78 || eis! 369) aia) ae ee 
