AS DETERMINED BY FIVE PLATINUM-RESISTANCE THERMOMETERS. 
247 
May 28 . 
. 9-55CA 
Sept. 22 . 
. 14-42a' 
29 . 
. 9-59 
23 . 
. 14-41 
30 . 
.. 9-63 
> Coil A. 
24 . 
. 14-41 
>Coil B. 
31 . 
. 9-66 
— 
25 . 
. 14-40 
J 
June 1 . 
. 9-70 1 
26 . 
. 14-39 
2 . 
. 975 
j- Coil B. 
27 . 
. 14-37 
^Coil A. 
3 . 
. 9-80 
28 . 
. 14-35 
4 . 
. 9-82 J 
29 . 
. 14-34 J 
Discussion of the Observations. 
The first step in the discussion of the observations is to group them into monthly 
means, and thence to deduce the harmonic expressions which will represent the 
readings of each thermometer throughout the year. # 
In this part of the work I have adopted the Fahrenheit scale, as the observations 
had already been reduced to this scale for comparison with our other meteorological 
results, and as the observations of the same kind at Greenwich! and Edinburgh^ 
discussed by Professor Everett are expressed in the same scale, there seemed to be a 
distinct advantage in retaining it. 
On account of the inequality in the lengths of the calendar months I have dis¬ 
carded them altogether, and, as far as possible, have divided the year into twelve 
portions which are alternately thirty and thirty-one days in length. As the obser¬ 
vations are taken only once a day, it is of course necessary to have an integer number 
of days in each division, but the following scheme makes the differences in their 
lengths as small as possible, and with one exception, that of January, alternately 
thirty and thirty-one days. In Leap Year this exception would be removed by 
intercalating the extra day in January, instead of February. 
* Professor W. Thomson, “ On the Reduction of Observations of Underground Temperature,” ‘ Trans. 
Roy. Soc. Edin.,’ vol. 22, p. 409. 
f ‘Greenwich Observations,’ 1860 (cxciii.). 
I Professor Everett, ‘ Trans. Roy. Soc. Edin.,’ vol. 22, p. 429. 
