Mr. NAIRNE on Ice of Sea Water. 2^3 
January 29, at eight o’clock in the evening, I expofecl 
to the open air two fimilar jars, each 5 i inches deep and 
inch in diameter; one of which I fir all, for the fake 
of diftinftion, call a; the other, b. a was filled with the 
fea water; b with water taken out of a water tub, which 
was a mixture of rain and fnow water. In a two ther- 
mometers were placed ; one relied on the bottom ; the 
upper part of the ball ol the other was a quarter of an 
inch only below the furface ol the water; one thermo- 
meter was alfo placed in b, re fling on the bottom. The 
following table diews the refult. 
VefTe] 
Time. 
Therm, a 
Therm, a 
Therm, in 
• 
• 
the Top. 
the Bot- 
the open 
c 
tom. 
Air. 
A 
h ' 
60 
60 
! 9*5 
** t 
B 
8 oP.M. 
60 
A 
8 15 
. 40 
33 
• • 
B 
38 
1 
* i 
• 
A 
8 20 
35 
2 9-5 
B 
37 5 
The furface of the water in B covered 
with ice. 
A 
LO 
Ol 
CO 
3 i 
26.5 
B 
34 
Surface as before. 
A 
8 30 
29 
25 
No appearance of ice. 
B 
32 
The ice on the furface increafed. 
A 
8 32 
28.5 
24-5 
Ice began to appear on the furface. 
B 
32 
Quite frozen. 
A 
B I 
8 36 
28.2 
28.5 
32 
20 
Cryftals over every part of the glafs. 
As before. 
N. B. .-During the time in which thefe obfervations were made, the thermo- 
meter in the open air rofe half of a divifion. 
The 
