6 nri.I.KTlX 4!)S, r. s. APARTMENT 01 agriculture. 



Table II. — Monthly and annual precipitation at Grass Valley and Mow, Oreg., showing 

 the average, maximum, and minimum, for each month, from V>u5 to 1915, inclusive. 



[Precipitation data (in inches): Previous to December. 1 ■. to<.», from the < >rcgon- Washington Railroad & 

 Navigation Co., Grass Valley, <»reg.: since December, 1909, from the substation records. T=trace.] 



Year. 



Jan. 



Feb. 



Mar. 



Apr. 



May. 



June. 



July. 



Aug. 



Sept. 



Oct. 



Nov. 



Dec. 



An- 

 nual. 



1905 



0.76 

 1.00 

 2.65 



.55 

 2.56 



.95 

 1.18 

 3.58 

 1.33 

 2.20 

 1.75 



0.20 



.85 



. 18 



.02 



1.03 



1.47 



.46 



1.36 



.23 



1.16 



2.31 



0.05 

 1.65 

 1.60 

 .68 

 .68 

 .63 

 .25 

 .69 

 .76 

 .11 

 1.27 



0.03 

 .10 



1.06 

 .11 

 .10 

 .66 

 .35 

 .78 

 .58 



2.06 

 .65 



1.70 

 1.05 



.90 

 1.41 



.49 

 1.25 

 1.05 

 1.33 

 2.27 



.76 

 2.06 



1.30 

 1.85 

 .89 

 .37 

 .99 

 .89 

 .64 

 .42 

 1.39 

 . 66 

 .36 



0.36 

 T 

 .30 

 .22 

 .10 

 T 

 .00 

 .02 

 .06 

 .08 

 .57 



T 



.34 



.71 



.34 



.02 



.00 



T 



.T4 



.05 



T 



.05 



0.75 

 .35 

 .50 

 .12 

 .45 

 .20 



4.03 

 .21 

 .49 



1. 05 



1.14 



1.36 

 T 

 .20 



1.11 

 .87 

 .70 

 .33 

 .78 



1.87 



1.48 

 .23 



0.85 

 2.59 

 1.46 



1.12 

 3.31 

 2.76 



.30 

 1.30 

 1.45 



.88 

 2.89 



1.35 



2.22 

 2.68 

 1.63 



1.14 

 .88 

 .61 



2.12 



1.69 

 .88 



1.61 



8.71 



1906 



12.00 



1907 



13. 13 



190S 



7.68 



1909 



1910 



1911 



1912 



1913 



1914 



1915 



11.77 

 10. 39 

 9.20 

 13.33 

 12.17 

 11.32 

 14.89 









1.68 



3.58 



.55 



.87 

 2.31 



.02 



.76 

 1.65 

 .05 



.59 



2.06 



.03 



1.30 



2.27 



.49 



.89 

 1.85 

 .37 



.16 



.57 

 .00 



.20 

 .74 

 .00 



.84 



4.03 



.12 



.81 

 1.87 



T 



1.72 



3.34 



.30 



1.53 



2.58 



.61 



11.35 





14.86 





7.68 







The distribution of the precipitation usually is favorable for grow- 

 ing cereals, nearly all of the rain falling during the months from 



Fig. 4.— Experimental plats at the Moro substation in the spring of 1916, showing the run-oil' during the 

 melting of a heavy covering of snow. 



September to June. July and August are practically rainless. In 

 some years there is considerable run-off in the winter or early spring 

 (fig. 4). Soil samples taken to a depth of 6 feet on 20 plats in May, 

 1913, had an average of only 1 per cent more moisture than samples 

 taken on the same plats in November, 1912, though the precipitation 

 during the interval measured 5.5 inches. From September 1, 1914, 

 to February 28, 1915, the precipitation was 8.35 inches, but this 

 penetrated stubble ground to a depth of less than 2 feet. The rains 



