938 REPORTS ON THE STATE OF SCIENCE. 
valuable for wheat, thinks that lands now idle will be brought to its 
production, and even anticipates that the centre of wheat growing may 
reverse its historic direction of movement and return eastward. 
In 1904 Dr. William Saunders reported that Fort Simpson, on the 
Mackenzie River, was the most northerly point from which samples of 
wheat had been received. This is about 62° N. lat. Dondlinger’ is 
authority for the statement that spring wheat has been matured at . 
Rampart and Dawson, still nearer the Arctic Circle. It is fair to say, © 
however, that the latitude range of wheat in North America is from 
30°, latitude of New Orleans, to 60°, latitude of the northern boundary 
of Saskatchewan and Alberta, a belt of 30°. The areas of large and 
assured production may, however, always remain between 35° and 
55°, with more chance for northern than southern expansion. In 
RKurasia wheat reaches to Trondhjem (634°) and northern Russia, to a 
point in India below the Tropic of Cancer (to 219). This greater 
range of 40° is due to the cooling effects of the altitude of the high 
slopes and plateaux of northern India. By including the product of 
Mexico and the Central American States, though small, the North 
American range may also be greatly extended. Thus from Nicaragua 
to the Mackenzie River wheat reaches across 50° of latitude. 
Wheat is so important that every effort will be made to widen its 
areal and its latitude range. This will be accomplished in part by 
irrigation. In the last census year, 1899, 99 per cent. of Arizona 
wheat was irrigated. This territory is a small producer, but Colorado 
and Utah, much larger growers, watered 84 and 574 per cent. 
respectively of their wheat lands. The three States of the Pacific coast, 
which are larger producers, irrigate but a small part of their wheat. 
In the year named all the Cordilleran States, with Nebraska added, 
irrigated 14°1 per cent. of their wheat fields, and raised on this area 
17°7 per cent. of their crop. This shows that the yield can be enlarged, 
where wheat is already grown, by dry farming, as well as by bringing 
new lands under the ditch. The cost of irrigation works, however, 
may make extensive wheat growing impracticable, because other crops 
permit more intensive farming and offer larger returns. Our conclusion 
miust be that only a moderate expansion of American wheat will be due 
to irrigation. 
Agricultural enterprise and the importation of varieties may be 
expected to show, and indeed are now showing, much greater results. 
Some time ago the Department of Agriculture brought from the Crimea 
and naturalised in Kansas a red winter wheat which is described as high 
in hardness, yield, milling value, and resistance to disease. Various 
other Russian sorts have served to push the wheat areas westward into 
the vast semi-arid regions where water is too limited for extensive irriga- 
tion, and which, therefore, must be given over to pasturage unless the 
crops can be adjusted to small rainfall. These varieties belong to the 
durum, or so-called macaroni wheats, and are commonly raised not only 
in Russia, but Turkestan, Algeria, and other parts of the world where 
the climate is dry and hot. 
A climatic comparison of the Great Plains, which cannot grow the 
usual varieties beyond the one-hundredth meridian, shows that the 
American semi-arid belt has three inches more rainfall than the great 
1 The Book of Wheat, p. 5. 
