1880 .] 
55 
[Nichols. 
Table I. Observations of Temperature in Fresh Pond, Mass. 
Date. 
Height of Water in 
Pond above 
Cambridge Datum. 
Tempei’atu 
© 
© J 
3 
o C/3 
H S 
r- 1 o 
.j-i 
(h 
CD 
Eighteen feet ^ y 
from surface. $ ^ 
a* 
£3 CD 
1 & P- 
5’ 
Thirty-five feet 8 
more or less rr. 
from surface. £ 
o. 
CD 
Feet. 
O 
o 
o 
May 4, 1878 . . 
16.40 
16.5 
12.5 
8.5 
“ 14, ... 
— 
14.5 
14.5 
8.5 
June 4, ... 
16.11 
19. 
16.5 
8.8 
“ 12, ... 
15.68 
17.3 
16.8 
8.6 
“ 19, ... 
] 5.38 
20.5 
16.8 
8.7 
“ 25, ... 
15.30 
22.2 
16.6 
9.2 
July 2, ... 
14.99 
28.0 
16.7 
9.3 
“9, . , . 
14.57 
26.0 
16.4 
9.2 
“ 16, ... 
14.60 
25.3 
16.8 
9.6 
“ 23, ... 
14.38 
24.0 
16.8 
9.9 
Aug. 6, ... 
14.25 
24.0 
17.3 
10.1 
“ 13, ... 
14.75 
24.0 
20.1 
10.0 
“ 20, ... 
14.67 
24.0 
20.0 
10.2 
“ 27, • . . 
14.54 
22.3 
20.0 
10.0 
Nov. 7, ... 
13.66 
9.5 
9.2 
8.7 
Dec. 7, ... 
14.50 
4.5 
4.3 
4.5 
Jan. 2, 1878 * . . 
14.78 
0.5 
1.0 
1.0 
“ 14, ... 
14.68 
0.7 
1.3 
1.7 
“ 22, ... 
14.58 
0.9 
2.0 
1.8 
April 14, ... 
15.16 
6.0 
5.0 
4.4 
May 13, ... 
15.46 
18.5 
13.0 
8.3 
gate-house ; at this point the water was from seventy-five to eighty 
feet deep. 
During the greater part of the time a buoy moored in the pond 
has enabled us to identify the station and to take the samples in 
a nearly vertical line one above the other, but during a part of the 
time the position has been reached only ajiproximately, and the 
observations have been made from an unmoored boat. The 
results of the various observations are recorded in Table II, and 
are shown in the accompanying diagram, Plate I, together with 
’ the daily mean temperature as reported by the IT. S. Signal Service 
observer in Boston, and the daily observations of temperature 
made by the engineer at the pumping station of the water-works, 
to which the water flows from the pond by a closed conduit 
