506 AGRICULTURAL REPORT. 



"Wisconsin, is above 61°, and the process of lieadiug, which in lower and wanner 

 districts takes place early in l\Iay, throughout the northern sections of the 

 United States probably occurs late in Jlay or early in June, and the crop \s 

 harvested from the middle of July to the first of August. 



Those places in the northern States which do not enjoy a temperature of 61* 

 in June have this mean in July, and can therefore grow spring wheat, which is 

 sown from the 10th of April to the lO'th of May, and is sufficiently advanced to 

 re<jeive the benefit of the mean of 61°, which is sometimes barely reached in July 

 only, that for August often falling below it, and the wheat is harvested from the 

 lOtb to the 20th of September. In Aroostook county, in the extreme northeast 

 of Maine, the mean for July and August are about three degrees higher than in 

 Washington county, at the eastern extreme of the same State, at points where 

 observations have been made, and the wheat is sown in the middle of May and 

 Lai'vested from the last of August to the 1st of September. 



In the southern counties of isew Jersey, Pennsylvania, Ohio, Indiana, middle 

 . Illinois, Missouri, and Kansas the mean of 61° is reached iu May, and when 

 not grown iu elevated regions the wheat is ready for the reaper sometimes in 

 June, and generally not later than the 10th of July. In districts further south, 

 where not retarded by elevation above the general level, the harvest occurs m 

 June, and in Cabarras county. North Carolina, the " Early May wheat" has 

 ripened in the month from which it takes- its name, and in Montgomery county, 

 Alabama, near the southern limit of wheat-growing east of the Mississippi, it 

 ripens about the end of May. 



The. following observations on the amount of heat required by the wheat 

 plant in different countries and under difierent degi-ees of cloudiness may be 

 of interest iu this connexion. 



Under the comparatively clear sky of Germany, at Arnstadt, experiments 

 show that wheat requires from flowering to maturity 53 days, having a meau 

 temperature of 63°, making an aggregate of 3,339° Fahrenheit. 



In the neighborhood of Richmond, Virginia, the " Japan wheat " headed 

 30th of April, 1860, and was reaped 14th of June, 1860, a period of forty-six 

 days. During the thirty-one days of May the mean temperature was 66.3°, 

 an aggregate of 2,056°.23; for the fourteen days of June, 73.56°, an aggre- 

 gate of 1,029°. 84 ; from which we leara that from heading to maturity 3,086.07° 

 are required at Richmond, Virginia, when the early variety, known as the 

 " Japan wheat," is sown. 



At Haddonfield, New Jersey, early-sown " Mediterranean " wheat headed 

 on the 18th of May, 1864. For seventeen days the temperature had been at a 

 mean of 64.30°. From the 18th to the 31st of May, inclusive, a mean daily 

 temperature of 67.66° was observed, making an aggregate of 9470.27. The 

 thirty days of June enjoyed the high mean temperature of 69°.229, which 

 formed an aggregate of heat of 2,076.89°. The Avheat was cut on the 30th of 

 June, in forty-four days from heading, and required an aggregate of heat de- 

 rived from daily mean temperatures, as observed by a thermometer in the shade, 

 of ^,024.10°, having been hastened to maturity by the almost cloudless skies 

 from the 10th to the 30th of June, combined with intense heats of the last 

 week, and long-continued drought. 



In Monroe county. New York, the wheat headed on the 10th of May, 1859, 

 and was reaped on the Sth of July. To ascertain the amount of heat required 

 from heading to maturity, we observe that for the twenty days of May, which 

 enjoyed a mean temperature of 57.17°, there results 1,143.40°; for the thirty 

 days in June, with a mean temperature of 64.72°, an aggregate of 1,941.60° ; 

 and for the seven days in July, with a mean temperature of 68°.21, results 

 477.47°, which combined, forms a final aggregate for fifty-six days from heading 

 to maturity of 3,562.47°. 



