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 where the highest civilization has been developed, the 
result being correlated to these climatic conditions. 
The table of distribution according to rainfall (Table X XII, 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 
where 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 X XIII, 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 where 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. 
WHEAT. 
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 sown 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. ; 
