538 
BUI.I.ETIN OP THE BUREAU OF FISHERIES. 
Table I. — Hydrography of the New York Lakes — Continued. 
Lakes. 
A 
2 
at M. 
Per cent 
of Dmx. 
V 
2 
at M. 
Per cent 
of Dmx. 
Surveyed by — 
Date. 
Number 
of sound- 
ings. 
Scale of 
original 
map. 
Canadice 
19 - 5 
77 
9 - 5 
37 
City of Roches- 
1909 
283 
1:2,400 
ter. 
Canandaigua 
44. 0 
S 3 
26, 0 
3 ! 
Cornell Uni- 
1888-1890 
395 
1:40,000 
versity. 
d*’ 
33 
40. 0 
30 
1875-1878 
397 
Conesus 
4/ 
U. S. Geolog- 
1904 
1:62,500 
ical Survey. 
Hemlock 
1904 
1:62,500 
Keuka 
32 . 0 
ss 
18. 0 
32 
Cornell Uni- 
1884-1888 
470 
1:40,000 
versity. 
12. 5 
6. 6 
88. 0 
Skaneateles 
Green (Wis.) 
32* 0 
44 
23. 0 
32 
Wisconsin 
1898 
697 
1:20,000 
G e 0 1 ogical 
Survey. 
EXPLANATION OF TABLE I. 
In table i the areas of drainage basins were taken from Rafter’s Hydrology of New York, except Canadice Lake, whose 
basin was measured from United States Geological Survey maps, and Green Lake, which was measured from Wisconsin maps. 
The drainage area of Seneca Lake includes that of Keuka Lake. 
Elevations above sea were from the United States Geological Survey maps, except Green Lake. In this case the elevation 
is that found in Gannett’s Dictionary of Altitudes in the United States, and refers to the railway station, which is somewhat 
below the level of the lake. 
Length, depth, etc., were measured or computed from the maps named in the table. 
The length of each lake was measured along its axis. That given for Keuka Lake is the length of the east arm and main 
lake; the west arm is 10.6 kilometers (6.6 miles) long. The maximum breadth of Keuka Lake is at the junction of the arms; 
elsewhere the maximum breadth is 1.48 kilometers (i.i miles). 
The mean breadth of the lakes was found by dividing the area by the length. The mean depth was found by dividing the 
volume by the area. 
The depths given for Hemlock and Conesus Lakes are those found by the authors. The lakes have not been surveyed, but 
probably these numbers are near the maximum depth. 
is the ratio of the mean depth to the maximum depth. 
The volume assigned to each lake in this table is the sum of the volumes of the several strata as given in the tables of detailed 
hydrography (p. 597). These are computed from theformulan=A 
are the areas of the bounding planes of the stratum. 
(a+b+Vab) 
in which h is the contour interval, A and B 
The mean slope was computed according to the formula of Gravelius a S = 
H (5^/04- /l + /2~t~ 
, in which H 
is the depth of the lake, A its area, and /o, /i, etc., the length of the successive contours. 
The mean slope of the areas between the several contours in the detailed tables of hydrography was calculated from the 
formulas = - in which h is the contour interval, a the area between the contours, and /i, h the length of the contours. 
0(2) 
Shore development is the ratio of the perimeter of the lake to the circumference of a circle whose area equals that of the lake. 
Volume development is the ratio of the volume of the lake to that of a cone whose base equals the area of the lake and whose 
height is the maximum depth of the lake. If the sides of the lake were vertical the volume development would be 3 or the 
volume would be that of a cylinder of equal base and altitude. The formula is and the numbers of this column are there- 
Dmx 
fore three times those in the column That part of the number which follows the decimal point is, in these lakes, the same 
as Peucker’s figure for ‘^mittlere Wolbung.” 
— at m. This column shows to the nearest meter or half meter the depth at which the area of the lake basin is reduced to 
2 
one-half of that of the lake’s surface. 
V 
— at m. shows in like manner the depth of the plane which divides the volume of the lake into two equal parts. 
2 
The columns headed “per cent of Dmx “ show the ratio of these depths to the maximum depth of the lakes. 
See account of Otisco Take (p. 542) for other statistics. 
® Gravelius, H.: Die mittlere Boschung. Zeitschrift fiir Gewasserkunde, bd. ix, p. 267. 
