A UMNOI^OGICAIv STUDY OF THE FINGER TAKES. 
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maps of the Cornell survey for all lakes except three. Canadice Lake was surveyed by 
the Rochester water department, and no hydrographic survey has been made of Conesus 
and Hemlock Lakes. The facts regarding their area have been taken from the maps 
of the United States Geological Survey and those of depth come from the observations 
of the authors. 
The style of publication for the maps of the six lakes surveyed by Cornell Univer- 
sity was a matter that caused much hesitation. The authors would have preferred for 
many reasons to use the metric system, but they decided on the use of the foot-and- 
mile scale in order to show the shore topography by means of the maps of the United 
States Geological Survey. These topographic maps are engraved on this scale, and it 
was easy to insert the hydrography on the plates, while the cost of reengraving the 
topography on the metric scale was prohibitive. 
All of the primary measurements are based on the metric system. Each sounding 
was converted from feet to meters before being platted on the working maps. The maps 
were enlarged to twice the scale of the original or to four times that scale in cases where 
the slopes were steep and the contours crowded. The measurements of areas were 
made with great care and repeated. It need not be stated that the number of sound- 
ings, especially in Cayuga and Seneca Lakes, is not enough to insure great accuracy of 
detail in the contours; but as all of these lakes are simple, straight, narrow, steep- 
sided troughs, without islands, bays, or marked irregularities of outline or of bottom, 
the results are approximately correct, and no subsequent survey is likely to make 
substantial alterations in them. 
The contour interval of 10 meters was chosen for the primary measurements because 
of the nature of the temperature curve. The epilimnion is from 9 meters to 15 meters 
thick, and for computing temperatures the volume of the o-io-meter zone, etc., must 
be known. In the small lakes the contour interval is 5 meters. For determining the 
volume of the several lakes the areas bounded by the several contours were measured, 
the volume of each zone was computed, and the total volume of the lakes as given in 
table I is the sum of the volumes of the several zones. 
In the detailed tables of the appendix the areas and volumes of the lakes are given 
in feet as well as in meters. The primary computations were all made on the metric 
system and the areas of the lakes at the 50-foot or 2 5-foot contour intervals were derived, 
not from the replatting of the lakes for engraving the maps, but from the hypsographic 
curves derived from the metric measurements. These areas agree essentially with those 
shown on the maps, but of course small differences appear. 
In preparing the maps for the engraver the Cornell soundings were platted on the 
outlines of the United States Geological Survey maps and the contours drawn again 
for this purpose. 
The Cornell maps are based upon a detailed survey of each lake; not only were 
the lakes sounded but their outlines were determined by a careful trigonometrical 
survey. The sounding line was of wire; an apparatus was provided for releasing the 
weight when the bottom was reached and a registering apparatus recorded the depth. 
The first machine employed is no longer in existence, but the second one, and that 
