Nichols.] 
62 
[October 6, 
sample of his records: “March 27, 1844. — Temperature of the 
water of the lake in contact with the ice, 32° [0° c.] ; six feet 
below the surface, 32|° [1°.3 C.]; twelve feet below, 34|° 
[1°.4 C.] ; and twenty-five feet below, being the whole depth of 
the lake at that place, 35^° [1°.9 C.]. These observations were 
made nearly one-fourth of a mile from the shore and after the 
lake had been covered with ice about eight weeks.” * In April, 
1851, a few days after the disappearance of the ice, the tempera- 
ture was found to be 36^° F. (2 C .5 C.). 
Buchanan found that the temperature of the water in Loch 
Lomond on January 28 and 29, 1879, was 36°. 3 F. (2°.4 C.), at the 
bottom where the depth was sixty-five feet. Forel found in the 
Lake of Morat a temperature of 2°. 7 C. at the lowest depth 
reached, which was forty meters ; in the deeper Lake of Zurich, 
the temperature increased regularly downward, reaching 3°. 9 at 
one hundred meters, and 4° at one hundred and twenty meters 
from the surface. 
In addition to the observations already mentioned, I have 
found only one other published set, namely, those made through 
the ice on Mystic Pond, January 2, 1861, by Henry Mitchell, 1 
IT. S. Coast Survey. He found a temperature of 36° F. (2°.2 C.) 
at thirty feet, and 37°. 5 (3°.l C.) at fifty feet from the surface. 
It seems, then, to be a fact that the water of lakes and ponds 
is, as a rule, before freezing, cooled to a temperature much lower 
than 4° C., not simply at the surface, as generally stated, but to a 
considerable depth. The commonly received idea and the current 
statements of the text-books of chemistry and physics are there- 
fore misleading. Thus Roscoe and Schorlemmer 2 say with refer- 
ence to lakes and rivers, “ the temperature of the whole mass is 
reduced to 4° C., after which the surface water never sinks, 
however much it may be cooled, as it is always lighter than the 
deeper water at 4°. Hence ice is formed only at the top, the 
mass of water retaining the temperature of 4°.” Ganot 3 says, 
1 Special Report of the U. S. Commissioners on Boston Harbor, Boston, 1861. 
2 Treatise of Chemistry, London, 1878, Vol. I, p. 224. 
3 Elementary Treatise on Physics, translated by Atkinson. 6th Amer. ed., 1873, 
p. 247. 
