4 ^ THE BOOK OF WHEAT. 



The results of recent investigations have shown that improve- 

 ment by selection is relatively a slow process 



DISTRIBUTION. 



Longitudinal. The migration of wheat has necessarily been 

 closely connected with the migration of peoples, and especially 

 with those of Europe. Consequently its general direction of 

 spreading has been westward, though it is claimed that it 

 spread eastward to China at a very early date. 



In the United States, the meridian bisecting the wheat acre- 

 age passed through eastern Ohio in 1850, and was about 81 

 degrees. In 1860 it was 85 degrees 24 minutes, in 1870 88 

 degrees, and in 1880 it had reached middle Illinois, 88 degrees 

 45 minutes. The center of wheat production at the time of 

 the census in 1900 was near the east central border of Iowa, 

 the meridian of 95 degrees. This shows that the westward 

 march of wheat proceeded at a much more rapid pace from 

 1880 to 1900 than from 1860 to 1880. During the last half 

 of the nineteenth century, the center of wheat production 

 moved west about 680 miles and north about 99 miles. 



Latitudinal. As European peoples and their descendants 

 are meeting the demands of increasing population by con- 

 tinually subjecting to cultivation land of colder and of warmer 

 latitudes, the domain of wheat is being extended on both 

 sides of the temperate zones. In 1887 Sering published a map 

 of North America in which he gave as the northern boundary 

 of wheat growing territory a line beginning south of Lake 

 Ontario running fully half way around it, a little north of the 

 northern boundary of the other Great Lakes, through Lake of 

 the Woods, through the southeast end of Winnipeg lake, 

 northwest to the Athabasca river, following this to the Rockies, 

 and beginning again in northeastern Washington. 



In 1894 the editor of the Social Economist denied that 

 wheat could be raised in Canada or Siberia north of the 55th 

 parallel. This widespread notion that wheat could not be 

 raised in the far north was gradually dissipated as wheat 

 crept closer and closer to the Arctic circle. Wheat has fre- 

 quently been matured at Sitka, Alaska, 56 degrees north lati- 

 tude. At the Sitka station, winter rye, spring wheat, barley, 

 oats and buckwheat matured both iri 1900 and 1901. In the 



