318 



average January temperature is below the freezing point. This same 

 condition marks most of the great wheat regions of the world. 



The wheat countries (which are also the countries of oats, barley, 

 and rye) are where the summer season only is the growing season, 

 and the comforts of winter must be provided for by forethought and 

 labor; and hence they are also the countries of labor, industry, and 

 enterprise, and wdiere the highest civilization has been developed, the 

 result being correlated to these climatic conditions. 



The table of distribution according to rainfall (Table XXII, p. 16) 

 shows that 132,152,234 bushels, or 28.8 per cent of the crop, grows 

 with an annual rainfall of between 40 and 45 inches, 62.7 per cent 

 Avhere it is between 35 and 50 inches, and 92.4 per cent where the 

 annual rainfall is above 25 inches, although some important wheat 

 regions, notably those of California, are where the mean annual 

 rainfall is less than 25 inches. We have an explanation of this in 

 the seasons at which the rain falls. The table of distribution accord- 

 ing to the rainfall of the growing season (Table XXIII, p. 16) shows 

 that 220,656,637 bushels, or 48 per cent of the crop, grows where 

 from 20 to 25 inches of rain falls during this season, and 366,381,658 

 bushels, or 79.7 per cent, where the rainfall during the growing 

 season is from 15 to 25 inches, 6.4 per cent wdiere it is below 15 inches, 

 and only 1 per cent where it is less than 10 inches — a fact of much 

 significance for great tracts of our country. 



CULTIVATION OF CEREALS— EXPERIMENTS AT BROOKINGS, 

 S. DAK. 



The first annual report of this station, for the year ending June 30, 

 1888, gives following table of results of experiments on different 

 varieties of wheat, at Brookings, S. Dak. (lat. 44.3° N.; long. 98.5° 

 W.), in April and May, 1887, on plats of ground that had already 

 borne one crop of wheat or flax or oats. Some were soAvn broadcast 

 and had no subsequent cultivation; others were "drilled by hand" 

 and subsequently hoed twice or thrice. 



The columns giving the calculated sums of degrees of temperature 

 are based upon observations at the Signal Service station at Huron, 

 some distance to the westward, because the special station at Brook- 

 ings was not then established. The meteorological table for Huron 

 follows the agricultural tables, so that the student may make such 

 further studies as he desires. A fragment of the meteorological 

 record at Brookings for 1888 is given in the station Bulletin No. 5, 

 which I have compared with the record for Huron and find that no 

 important error will result from using the Huron records. 



