198 
Range of Wide 
No. Tube. 
41-6—51:0 
41-0—51°0 
36-0—54-0 
30°5—55-0 

39°5—52°9 
38°5—53°2 
35:0—55'9 
26°5—60'0 
40:5—51°5 
40°7—50-7 

TABLE III. THERMOMETRIC CONSTANTS. 
Inches 
of Wide} Degrees 
Tube in| in Fine 
Fine Tube. 
Tube. 
Length of Length of | Degrees of 
Fine Tube 1° in inches} Fine Tube 
sunk below 
ground. 
of Fine 
in inches. 
Tube. 



OBSERVATORY. 
13-7 | 316 
4-5 | 162 
48| 86 
57 | 48 
EXPERIMENTAL GARDEN. 
30°0 | 24°5 
9:2 8-4 
4:2 6:2 
1:8 3°8 
CRAIGLEITH. 
PROFESSOR FORBES ON THE TEMPERATURE OF THE EARTH. 
Degree 
from which 
the column 
exposed to 
external 
temperature 
is reckoned. 
19°7 
81 | 49 
12°5 
3:2 
37:0—53°6 ; 10 6:4 65 
31:5—55°4 : 10 1:4 2°1 


* This supposes the Atmospheric Temperature to penetrate 9 inches. The tubes at the surface 
would have the following readings :— 
41-2 40°7 35:5 29:4 | 389 38:2 34:3 25°7 | 401 40:5 36:2 31:1 

May 14. 1834, No. 4. Observatory was lowered 3°12, by withdrawing alcohol. May 15, No. 4. 
Craigleith lowered by 1°.95. Corrected scales were immediately applied. 
In the above Table, No. 1 is the longest, No. 4 the shortest, Thermometer. 

VI. Corrections of the Observations. 
It is very evident that the readings of the thermometers cannot indicate ex- 
actly the temperature of the point corresponding to the centre of the bulb, be- 
cause the stem between that point and the surface of the ground never has a uni- 
form temperature throughout; and the portion of the column above ground is 
affected by the temperature of the air at the moment. Of these two corrections 
in our thermometers, the latter is by much the most important, which is fortunate, 
because it is also determined with the greatest accuracy. 
These corrections, however obvious, have, according to M. QUETELET, been 

