HYDROLOGY OP NEW YORK 87. 



further rough guide it remains to point out that in case a given 

 record does not conform substantially to the foregoing it may be 

 assumed that either the minimum or the maximum, as the case 

 may be, is still to occur. Near the seacoast, where the supply of 

 moisture in the air is more nearly constant, there is less variation 

 than in the interior, and the rule that the maximum is double the 

 minimum is more generally true. This proposition is also gener- 

 ally true as regards English meteorology. 



Is rainfall increasing? This question has been discussed by 

 Prof. Mark W. Harrington, 1 who, however, reached no very defi- 

 nite conclusion, although he is disposed to answer it in the 

 negative. The method of discussion followed was to reduce the 

 annual rainfalls to a series of means of each five years. These 

 means were entered on a succession of maps, five years apart in 

 time, and on these maps were drawn the line of 40 inches of 

 annual rainfall. The question to be determined is, as we draw 

 this line for each five-year mean, does it change its position in 

 any regular and systematic way? 



An examination of the detail shows that while these lines are 

 subject to limited fluctuations, there are no uniform or systematic 

 fluctuations. The line of equal rainfall for 1861-1865 occupied 

 nearly the same position as the line for 1886-1890. The varia- 

 tions are sometimes extensive, but without systematic progress. 

 Professor Harrington therefore concludes that with the data at 

 hand there is not sufficient evidence of systematic fluctuation of 

 the rainfall. 



Relation of rainfall to altititde. This matter has been referred 

 to in a discussion of Mr Noble's paper, Gagings of Cedar River, 

 Washington, 2 where the statement has been made that in the 

 8tate of New York the rainfall records show both increase and 

 diminution of precipitation with increase of altitude. The 

 Hudson river catchment area shows a higher precipitation at the 

 mouth of the river than it does at its source in the Adirondack 



1 Rainfall and Snow of the United States, Compiled to the End of 1891; 

 with Annual, Seasonal, Monthly, and other Charts, by Mark W. Harring- 

 ton: Bulletin C, Weather Bureau, U. S. Dept. of Agriculture. 



2 Trans, Am. Soc. Civil Eng., Vol. XLI, pp. 1-26. 



