rTTYKICAT. A^D CLIMATIC ,%'ETTING 21 



State Experiment Station at Chatham, Alger 

 County, has computed the number of hours during 

 which the sun is above the horizon for the period 

 of six months from April 15 to October 15, for 

 latitude 42 degrees north (approximately of Cold- 

 water, Hillsdale and Adrian in the most southerly 

 tier of counties) ; for latitude 43 degrees north 

 (approximately of Port Huron and Grand Eapids) ; 

 and for latitude 47 degrees north (approximately 

 of Houghton on the Keweenaw Peninsula, Lake 

 Superior) ; and he has ascertained the excess of 

 possible sunlight for the forty-seventh parallel to 

 be 56.33 hours when compared with the forty-third 

 parallel, and to be 69.13 hours, when compared 

 with parallel 42.^ The particular conclusion which 

 Geismar derives from the foregoing study is that 

 the Upper Peninsula of Michigan is very favorable 

 to the growth of the sugar-beet, because the con- 

 version of starch to sugar goes on in the presence 

 of sunlight, and, consequently, that one may expect 

 a greater sugar-content in beets grown in the north- 

 ern peninsula as compared with the southern coun- 

 ties of the State. 



The northern latitudes not only have an advantage 

 over the southern in regard to their quantity of 

 sunlight, but also in respect to twilight. Com- 

 putations of the end of twilight for various latitudes 

 falling within the boundaries of Michigan, made 

 by W. J. Hussey, professor of astronomy of the 



^Forty-second Ann. Kept. vState Bd. Agr., Mich., 1903, 

 p. 279. 



