MICHIGAN ACADEMY OF SCIENCE. 
85 
STATIONS.-— Concluded. 
No. 
Station. 
Long. 
Lat. 
Elevation. 
No. 
of 
years. 
Average 
annual 
precipi¬ 
tation. 
Reference 
station. 
Averages at 
reference station. 
Mean 
annual 
precipi¬ 
tation for 
1880-1904. 
25 years. 
n. years. 
121 
Port Huron. 
82.5 
43.0 
639 
25 
20.7 WB 
122 
81.5 
41.3 
1 053 
13 
37.92 
34. i7 
32.82 
123 
Cleveland, 0. 
81.7 
41.5 
627 
25 
34 2 WR 
124 
Saugeen, Ont. 
81.3 
44.5 
656 
25 
125 
Port Stanley, Ont. 
81.2 
42.7 
579 
24 
35.33 
Erie, Pa. 
38.04 
37.76 
35.6 
126 
Stratford, Ont. 
81.0 
43.4 
1,190 
8 
40 59 
127 
Newcastle, Pa. 
80.3 
41.0 
800 
6 
38.50 
Pittsburg. 
36^83 
38 A 4 
37! 2 
128 
Erie, Pa. 
80.1 
42.1 
600 
25 
129 
Parry Sound, Ont. 
80.0 
45.3 
635 
25 
39.7 
130 
Pittsburg, Pa. 
80. 
40.5 
842 
25 
2S.2 WR 
131 
Franklin, Pa. 
79.8 
41.4 
955 
18 
40.87 
38.04 
38.90 
132 
Toronto,- Ont. 
79.4 
43.7 
260 
25 
31.1 
133 
79.2 
41.9 
1,137 
18 
43.42 
38.04 
37.15 
134 
Buffalo, N. Y. 
78.9 
42.9 
690 
25 
135 
82.7 
42.1 
606 
6 
34 50 
136 
Maidstone, Ont. 
82.9 
42.2 
627 
6 
28.97 
137 
80.8 
43.9 
6 
33.56 
138 
Durham, Ont. 
80.7 
44.2 
6 
43.08 
139 
80.0 
43.6 
850 
6 
31.77 
140 
Orillia, Ont. 
79.4 
44.6 
775 
6 
31.99 
Parry Sound.. 
39.72 
37 A3 
Zi.7 
141 
81.7 
43 5 
6 
36 36 
142 
Listowell, Ont. 
80.9 
43.7 
1,260 
6 
38.75 
34 29, 
143 
Port Dover, Ont. 
80.2 
42.8 
'636 
6 
32.73 
Erie. 
38.04 
42.83 
29.1 
If we glance at Fig. 4 we shall see that the heavy rains occur not 
merely to southeast of the Lakes, as Harrington pointed out in 1894, but 
rather where strong slopes lie in this position. See especially in On¬ 
tario east of Lake Huron, in the lower peninsula of Michigan, between 
Lake Michigan and the strong northwest-facing slopes north and south 
of the Saginaw valley, in the highlands along the boundary of northern 
Wisconsin and the upper peninsula, and in the strong ascent from Lake 
Erie to the Allegheny plateau. In this latter region it is interesting 
to note the slightly diminished precipitation in the valleys, as at Pitts¬ 
burg and Newcastle. Very remarkable is the V of less than thirty 
inches—four stations—northwest of Detroit and coinciding with the 
lower land among the hills that culminate at Ball Mt., in Oakland 
county. H. V. Payne, 1889 (?) pointed out this effect of the Ontario 
elevation in extracting greater rainfall from the winds that prevail 
here from the west. Fig. 1 shows it to be present throughout the whole 
region. All slopes to leeward of the Lakes get heavier rainfall. Shores 
to windward of the Lakes are equally characterized by light precipita¬ 
tion, as at Milwaukee, the thumb of Michigan and Toledo, the west 
end of Lake Ontario and north of the east end of Lake Erie. Increase 
of precipitation with elevation is familiar to students of rainfall in 
all situations where slopes oblige rain-bringing winds to ascend. Prof. 
Hann recommends it as a desirable improvement in drawing charts of 
the monthly rainfall in the United States that base maps with thou¬ 
sand-foot contours be used and some regard had to these in drawing 
isohyetals. 
Our rainfall is provoked by ascensional movement within cyclones or 
in thunderstorms within cyclonic areas. Easterly and southerly winds 
