56 The Principles of Fruit-growing. 



ones are. That is, what may be gained by atmos- 

 pheric drainage may be more than overcome by the 

 coldness of elevation. The table (page 55) from the 

 New York Meteorological Bureau*, compares the 

 monthly average temperatures of high and low sta- 

 tions. The high stations give, with but two slight 

 exceptions, a lower reading than the low stations do, 

 but the differences are least, as a rule, in the win- 

 ter months, when the effects of atmospheric drainage 

 are apt to be least marked. 



Thermometer readings taken upon the slope of 

 East Hill, at Ithaca, New York, during January and 

 February, 1897, also show the lower average tempera- 

 tures of very high lands. t The top of this hill is 

 about 400 feet above the valley. Six thermometers 

 were placed along its slope, No. I. being at the 

 foot of the hill, and No. VI. at its top. Tempera- 

 tures taken at night would probably have shown 

 more marked differences. It is probable, however, 

 that if observations were made at night in still wea- 

 ther in spring or fall, between the valley and lands 

 from fifty to one hundred feet above it, the higher 

 lands would have given the higher figures, in con- 

 sequence of the settling away of the cold air. It 

 is well known, for example, that ravines along a fruit 

 plantation often carry away the cold air and save 

 the fruit from light frosts, and also that planta- 

 tions opposite the mouths of gullies are likely to 

 suffer. The Ithaca figures now follow: 



* Fifth Ann. Rep. Meteor. Bureau, N. Y. 388. 

 tMade for me by my student, S. L. Sheldon. 



