A NEW EVAPORATION FORMULA 
11 
The average elevation of all the anemometers above the ground at these 15 
stations is about 100 feet, which is about the same as the average elevation of the 
anemometers at all of the regular U. S. Weather Bureau stations in the United 
States. 
INFLOW INTO LAKE MICHIGAN-HURON, (7 3 ); OUTFLOW FROM LAKE SUPERIOR (/<) 
The inflow into Lake Michigan-Huron from Lake Superior through the St. 
Mary's River, the 7 3 of equation (1) for Lake Michigan-Huron, was computed from 
the formula 
Discharge of St. Mary's River = 46,730+ 15,300 X(S. W. Pier -600.0) cu. ft. per 
second (2) 
in which "S. W. Pier" is the elevation above mean sea-level of the water surface at 
the S. W. Pier at Sault Ste. Marie. The flow through the power plants and locks 
Table 2 — Regular U. S. Weather Bureau and Canadian Meteorological Service Stations near Lake Superior 
Station 
Latitude 
Longitude 
Elevations in feet 
Barometer 
above 
sea 
Thermometer 
above 
ground 
Rain 
gage 
above 
ground 
Anemometer 
above 
ground 
In the United States: 
Sault Ste. Marie 
46° 30' 
40 34 
47 07 
46 47 
48° 27' 
84° 21' 
87 24 
88 34 
92 06 
89° 12' 
614 
734 
668 
1133 
644 
759 
11 
77 
62 
11 
4.5 
33 
3 
70 
57 
3 
1 
27 
52 
111 
99 
47 
100* 
82 
Marquette 
Houghton 
Duluth 
In Canada: 
Porto Arthur 
1 Approximate elevation of ground above mean lake level, 40 feet. 
3.20+1.05 (S. W. Pier-600.0) 
(3) 
is included in the above formula. Equation (2) converted to units of 0.001 foot 
of depth per day on Lake Michigan-Huron, the unit used in equation (1), is 
Discharge of St. Mary's River 
in 0.001 ft. of depth per day 
on Lake Michigan-Huron 
The outflow from Lake Superior into Lake Michigan-Huron through the St. 
Mary's River, the h of equation (1) for Lake Superior, is also equation (2) if ex- 
pressed in cubic feet per second. If expressed in 0.001 foot of depth per day on 
Lake Superior, the unit used in equation (1), it is 
Discharge of St. Mary's River 
in 0.001 ft. of depth per day on 
Lake Superior 
= 4.53+1.49 (S. W. Pier-600.0) 
■(4) 
Lake Superior being the highest lake in the chain of Great Lakes, there is no 
inflow into it from a lake above, so I 3 for Superior is zero. 
Formula (2) was taken from the U. S. Lake Survey Records. 
