esulted.

[24] In order to yield a crop of twenty-five bushels per acre the soil
must supply 110 lbs. of nitrogen, 45 lbs. of phosphoric acid, 30.5 lbs.
of lime, 14.5 lbs. of magnesia, and 142 lbs. of potash; these are
approximately the mineral elements taken out of the soil with each crop,
and it is needless to say that they must be replaced or the grain will
starve for want of nutrient substances.

[25] In the United States there are about seven wheat-districts, each
characterized by particular varieties that grow best in the given
locality. In the New England and most of the middle Atlantic division
Early Genesee Giant, Jones Winter Fife, and Fultz are chiefly grown. In
the Southern States Fultz, Fulcaster, Purple Straw, and May are
foremost. In the north central group of States Early Red Clawson, Poole,
Dawson's Golden Chaff, Buda Pest, and Fultz are common. In the Dakotas
and Minnesota Scotch Fife and Velvet Blue Stem (both spring wheats) are
generally planted. In Kansas and Texas and the adjacent locality the
principal varieties are Turkey, Fulcaster, and Mediterranean (all winter
wheats). In California and the southern plateau region Sonora,
California Club, and Defiance are the principal kinds (all winter
wheats). In Washington and Oregon Little Club, Red Chaff, and Blue Stem
(which are either winter or spring) are the main varieties.

[26] Sometimes the owner sends it to the nearest elevator at tide-water
where the grain is stored, not in bulk, but in the original packages,
subject to his demand. In the course of a month or six weeks it absorbs
so much moisture that the gain in weight more than pays the storage
charges.

[27] The elevators are equipped with "legs" or long spouts, within which
belts with metal scoops transfer the grain from car to vessel or _vice
versa_. The elevators at Buffalo will fill a canal-boat in an hour's
time, or load six grain-cars in five minutes. A large whaleback
steamship may be relieved of its 200,000 bushels in about three hours.
Most of the east-bound wheat of the Middle West is transferred to the
seaboard by rail, but that of the northwest, which forms the chief part
of the crop, is shipped from Duluth through the St. Marys Falls Canal to
Buffalo, where it is transferred to cars or to canal-boats. New York is
the leading export market, but Boston, New Orleans, Galveston,
Baltimore, and Philadelphia are also important shipping ports.

[28] The following is approximately th