317 
more upon the variety cultivated than upon either soil or climate. 
The spring wheat of Dakota and Minnesota produces as strong flour 
as does grain from a sunnier climate. It is true that certain varieties 
of very hard wheats only grow in hot, dry climates. Such is said to 
be the case with the best macaroni wheats. It is claimed that the 
macaronl wheats of California are equal to the best of northern 
Africa or of southern Europe and that the macaroni made from it in 
San Francisco is equal to the best Italian. But while, as a whole, 
the quantity of gluten and the strength of the flour is determined more 
by the variety of wheat than by the climate or the soil, yet both of the 
latter have their influence on chemical composition. Although direct 
chemical evidence is lacking, derived from a large number of chem- 
ical analyses from samples chosen with this special object in view, 
it is claimed that abundance of phosphates in the soil increases the 
quantity of gluten in the crop. The millers of western New York 
say that the flour has grown stronger with the increase in the use of 
superphosphates in growing wheat in that region, and that the same 
has often been stated as a fact in English experience. 
The particularly bright character of American grain, however, 
depends upon the climate rather than upon the soil. The sunny 
climate of the whole United States south and west of New England 
is favorable for this, and from the time of the first settlement of 
the colonies the bright color of American grain, as compared with 
that of northern Europe, particularly that of Great Britain, has been 
remarked. 
The table of distribution according to annual temperature (Tenth 
Census, Cereals, Table XIX, p. 14) shows that the greatest produc- 
tion is where the mean annual temperature is between 50° and 55°, 
173,895,149 bushels, or 37.8 per cent, being grown in this belt, and 
136,401,822, or 29.7 per cent, where the mean annual temperature is 
between 45° and 50°. Adding these two, we see that 310,296,971 
bushels, or 67.5 per cent, is grown where the mean annual tempera- 
ture is between 45° and 55°. Considered in respect to the mid- 
summer or July temperature (Table XX, p. 14), which has much to 
do with the ripening of the grain, our figures are of less interest in 
this crop, because over considerable regions of the country the crop 
is already ripe before July begins, notably in California; but we 
find that 223,852,371 bushels, or 48.7 per cent, grows where the mean 
temperature of July is between 70° and 75°, and 178,530,037 bushels, 
or 38.9 per cent, where the midsummer temperature is between 75° 
and 80°, or an aggregate of 87.6 per cent where the July temperature 
is between 70° and 80° and 97.3 per cent where it is between 65° and 
85°. While the ideal climate for wheat is one of mild winters, and 
some of the most noted wheat regions of the world are where snow 
and frozen ground are unknown or very rare (as in Egypt, India, 
and California), nevertheless most of the wheat of the world grows 
in regions of cold winters. 
The table of distribution according to mean winter temperature 
(Tenth Census, Cereals, Table X XI, p. 15) shows that in this country 
46.6 per cent grows where the mean January temperature is between 
20° and 30°, 68.9 per cent where it is below 30°, and it is safe to say 
that 70 per cent of the wheat crop of the country is grown where the 
