86 
EIGHTH REPORT. 
prevair during our rains over all the east part of tine United States, 
because other winds come to us from regions ill-supplied with moisture 
in comparison with the air over Atlantic and Gulf. It is for this rea¬ 
son of course that the rains augment pretty steadily as the eastern and 
southern coast is approached from the west. The vapor condensed here 
rose originally from the ocean. The Lakes are mere pools of this rain 
condensed from vapors of marine origin, lingering in hollows on their 
way to the sea. The widening of the belt of thirty-inch rainfall that oc¬ 
curs near the Lakes, implies at most an addition of five or six inches 
by reevaporation from the surface of the Lakes themselves. 
92 91_90 89 88 67 86 63 84 8J 82 81_80 79 78 
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Fig. 4. —Dotted areas above 1,000 feet; lined areas above 1,500 above sea level. 
The somewhat high rainfall on the east coast north of Saginaw Bay 
is the record of the single station, Harrisville. It is not apparent why 
it should be large. It would be prudent to examine the gage and its 
exposure. 
It was shown by the table, at page 3, that the i*ainfall at neighboring 
places was roughly sympathetic without closeness of correspondence. 
Neighboring places have heavy rains usually in the same years and so 
also their light rains. The failures in this correspondence are as in¬ 
teresting as the agreements. An instance was found in reducing the 
sixteen-vear record of Sault Ste. Marie by using Marquette and Alpena 
as alternative reference stations. During those first nine years, Mar¬ 
quette’s rainfall was about the same as for the average of the entire 
twenty-five years. Alpena, on the contrary, had fairly 15 per cent more 
