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of seed rather than the influence of climate, since large crops have 
been and can be raised in this country. 
The injurious influence of hot, moist, and rainy weather has, he 
thinks, a general tendency to deteriorate the quality of American 
wheat, as the plant needs a hot and dry climate. Moisture defines 
the southern limit of wheat cultivation while the northern limit has 
not yet been found. In 1853 the growing season in England was too 
cold to ripen, the average being 57° F. for July and 59° F. for 
August, so that only one-half or one-third of the usual crop of wheat 
was harvested. 
In Bogota, Colombia, where the temperature of the high plains is 
quite low, wheat that is sown in February is harvested in the last 
week of July, or in 147 days, at a mean temperature of 58° or 59° F. 
At Quinchuqui wheat is sown in February and reaped in July at a 
mean temperature of 57° or 58° F. Hence Lippincott concludes 
that in general wheat requires a mean temperature of 60° during the 
last month of its maturity, or a mean temperature of 56° during the 
whole period of growth. 
In England in 1860 wheat sown March 28 ripened August 20. Of 
these 145 days there were 133 that had temperatures above 42° F. 
In 1861 130 days were required of temperatures above 42° F. 
When the temperature of the soil during the last phase of growth 
(viz., from earing to maturity) falls below 58° to 60° F. no progress 
is made in the growth, and unless 60° is exceeded the crop never 
fairly ripens. These figures appear to accord closely with the 
requirements of the wheat plant in the United States, where it is 
found that those regions having a mean temperature for May be- 
tween 58° and 60° F. can not mature the wheat in May, but those 
having a June temperature above 61° can ripen the wheat in that 
month.. Those having a temperature of 61° in July can mature 
spring wheat which is sown the 10th of April or the 10th of May. 
Those having a mean temperature of 61° in May can mature the 
winter wheat in that month. 
Lippincott gives the following items: At Arnstadt, Germany, 
wheat requires from flowering to maturity 53 days at a mean tem- 
perature of 63° F., or a total of 3,339° F.: 
At Richmond, Va., Japan wheat headed. April 30, 1860, and was 
reaped June 14, or 46 days, with a sum total of mean daily tempera- 
tures of 3,086° F.: 
At Haddonfield, N. J., Mediterranean wheat sown early, headed 
May 18, 1864, and matured June 30, or 44 days, with a sum total of 
3,024° F. of mean daily shade temperatures: 
In Monroe County, N. Y., wheat headed May 10, 1859, and matured 
July 8, or 56 days, with a sum total of 3,562° F. 
The preceding meager data are all that Lippincott was able to find 
