486 Eighth Annual Report of the 



sonts, approximate!}', the continental type, Blocli Island the mari- 

 time, and Palermo, in the Great Lake Region, a maritime type 

 varied by a secondary summer maximum. 



The Amounts of Annual Rainfall 



in different sections of the State are mainly determined, first by 

 proximity toi sources of vapor, vapor-laden air currents; and 

 secondary, by the character of local topography. In the case of 

 Kew York State a, more definite and substantially correct form 

 of the latter statement is that, under similar conditions, the 

 precipitation is roughly proportional to the altitude of land 

 surfaces. This rule does not apply to the central and southern 

 Atlantic States, whose mountain ridges are parallel to the 

 prevailing direction of vapor bearing winds. 



As has been stated, the Atlantic Ocean furnishes the principal 

 vapor supply of the northeastern States. While passing inland 

 with easterly winds the moisture is, in the first place, largely 

 precipitated over the mountains of New England, as is rendered 

 apparent by the extraordinary rainfall on Mount Washington, 

 averaging over 90 inches per annum. A similar effect is no 

 doubt due to the Green Mountain system near the New York 

 border; and hence the lowlands to the westward, including the 

 Champlain and upper Hudson valleys receive a somewhat 

 deficient supply as compared with that of the State as a whole. 

 A marked increase of rainfall is again found in the Adirondack 

 highlands, and beyond these .a decrease in the St. Lawrence 

 valley. 



Sea-winds from the southeaslt find no obstruction on the imme- 

 diate coast of New York; but passing inland meet the abrupt hill 

 ranges of the southeastern counties, and probably give to each 

 a copious rainfall as compared with thait of the intervening 

 valleys. Very few observations of rainfall have been made on 

 the eastern side of these ridges; and the above statement rests 

 mainly upon a two years' record of the mountain station Minne- 

 waska, which during that period obtained an excess of fourteen 



