e 
No. 373-] CLASSIFICATION OF LAKES, 33 
results thus far obtained seem to indicate that the first order 
will include only those lakes more than about two hundred feet 
in depth, such, for instance, as the Great Lakes, Lake Cham- 
plain, etc.; the second order will include those whose depth is 
less than about two hundred feet, but greater than about thirty 
feet ; and the third order will include those whose depth is less 
than twenty-five feet. These boundaries are only approximate, 
and it should be remembered that depth is not the only factor 
which influences the bottom temperature. 
Instead of citing long tables of figures giving the results 
thus far obtained, which would materially lengthen this paper, 
the writer prefers to cite a list of references which the reader 
may consult. 
LITERATURE. 
Wm. R. NICHOLS. On the Temperature of Fresh Water Lakes and Ponds. 
Proc. Boston Soc. Nat. Hist. Vol. xxi. 1880. (This paper contains 
. a bibliography of the subject to date.) 
HAMILTON SMITH. Temperature of Lakes. Trans. Amer. Soc. Civ. Eng. 
March, 1884. 
FREDERICK P. STEARNS. Temperature of Water. In Special Report of 
the Mass. St. Bd. of Health on Examination of Water Supplies. 
p-659. 1890. 
C. Dwight MarsH. Notes on the Temperature and Depth of Green 
ake. Trans. Wis. Acad. of Science, Arts, and Letters. Vol. viii. 
F. A. Foret. Le Leman, une Monographie Limnologique. 
ISRAEL C. RUSSELL. Lakes of North America. Ginn & Co. 1895. 
H. E. WARREN and GEORGE C. WHIPPLE. The Thermophone, a New 
Instrument for Determining Temperatures. Technology Quarterly. 
Vol. viii, No. 2. 
H. E. WARREN and GEORGE C. WHIPPLE. The Thermophone, a New 
Instrument for Obtaining the Temperature of a Distant or Inaccessible 
Place, and Some Observations on the bch seria of Surface Waters. 
Amer. Meteor. Journ. June, 1895. 
GEORGE C. WHIPPLE. Some Observations on the Temperature of Surface 
Waters, and the Effect of Temperature on the Growth of Micro- 
organisms. Journ. N. E. W. W. Assoc. Vol. ix, No. 4. 
GEORGE C. WHIPPLE. The Thermophone. Science. Nov. 15, 1895. 
DESMOND FITZGERALD. The Temperature of Lakes. Trans. Amer. Soc. 
Civ. Eng. Vol. xxxiv. August, 1895. 
W. F. GANoNG. Upon Temperature Measurements with the Thermophone 
in Clear Lake, Lebreau. Bull. No. 14, New Brunswick Nat. Hist. Soc. 
