OBSERVATIONS OF UNDERGROUND TEMPERATURE. 413 
TABLE III.—ANNUAL HARMONIC VARIATIONS OF TEMPERATURE. 






EXPERIMENTAL GARDEN. CRAIGLEITH QUARRY. 

CaLTON HILL. 













low sur ; nec : 
face in | Amplitudes Epochs of Maximum. Amplitudes Epochs of Maximum. Amplitudes Epochs of Maximum. 
hb A in d aaa ind _ 
a — In Degs. and | In Months be Sue In Degs. and | In Months ae mgs In Degs. and |In Months 
Mins, and Days. 

Mins. and Days. 


Mins. and Days. 




fe} 
7386 | 226 52 |Aug.19 291 40’ |Aug.13] 8-069 | 2990’ |Aug.14 





3 
6 5063 247 5 = |Sept. 8 239 20 31 6148 233 43’ 26 
12 2°455 287 30' |Oct. 19 281 27' | Oct.13] 4-216 256 42' |Sept. 17}- 
24 0:655 3656 |Jan. 6 355 0’ | Dec. 27 




1:836 305 46 |Nov. 7 
By taking the differences of the Napierian logarithms of the amplitudes, and the 
differences of epochs reduced to circular measure (are divided by radius), thus 
shown for the different depths, and dividing each by the corresponding difference 
of depths, we find the following numbers. 
TABLE IV.—RatTEs oF LOGARITHMIC DIMINUTION IN AMPLITUDE, AND OF RETARDATION 
In Erocu, oF ANNUAL HARMONIC VARIATIONS DOWNWARDS. 





CaLtTon Hix. EXPERIMENTAL GARDEN. CRAIGLEITH QUARRY. 
‘Depths below | Rate of Diminu- | Rate of Retarda- | Rate of Diminu- | Rate of Retarda- | Rate of Diminu- | Rate of Retarda- 
surface in | tion of Napierian | tion of Epoch in | tion of Napierian | tion of Epoch in | tion of Napierian | tion of Epoch in 
French feet. | Logarithm of Am-| Circular Measure, | Logarithm of Am-| Circular Measure, | Logarithm of Am-| Circular Measure, 
plitude per foot of per foot of plitude per foot of per foot of plitude per foot of per foot of 
Descent. Descent. Descent. Descent. Descent. Descent. 
BtoGfeet.| °1259 1176 1004 1163 09372 06399 
6 to 12 -1206 ‘1176 ‘1130 ‘1193 06304 -06690 
12 to 24 ‘1101 1129 1084 1062 06476 06690 
3 to 24 1154 ‘1149 "1082 71114 °06841 -06648 



16. Ali the numbers here shown for each station would be equal, if the con- 
ditions of uniformity supposed in the theoretical solution were fulfilled. The 
discrepancies are, with the exception of one of the numbers for Craigleith Quarry, 
on the whole small—smaller, indeed, than might be expected, when the very 
notable deviations of the true circumstances from the theoretical conditions are 
considered. The mean results over the 21 feet, shown in the last line, present very 
remarkable agreements: the numbers derived from amplitudes being identical 
with that derived from epochs for the Calton Hill station ; while the differences 
between the corresponding numbers for the two other stations are in each case 
only about 3 per cent. Taking that one number for the first station, and the 
mean of the slightly differing numbers derived from amplitudes and from epochs 
respectively, for the second and third, we have undoubtedly very accurate deter- 
. Te ¢ ; : 
minations of the value of if oe for the three stations, which are as follows :— 
VOL. XXII. PART II. oO 

