358 PROFESSOR FORBES ON THE CLIMATE OF EDINBURGH. 
in the centre of the lower part an unglazed opening 9 inches square, which 
admitted air freely to the interval between the brick wall and the window. 
The thermometer was suspended in this interval, into which the snow often 
drifted. 
4. The effect of this peculiarity of exposure would probably be to modify the 
extremes both of heat and cold, but (especially for observations taken at 9 a.m.) 
it was not likely to affect materially the mean results. 
5. The observations from May 1799 to November 1802, when the thermo- 
meter was moved into this position, seem (to judge by their results) to have been 
made probably within the house, and therefore I have not retained them in the 
following paper. Till August 1829 the observations were invariably made by 
Mr Fergus, senior, when the failure of his eyesight devolved them (I believe) 
upon some member of his family ; but they were still continued in all respects in 
the same manner until the commencement of September 1837, when the instru- 
ment was removed to a different situation in the town of Dunfermline, where it 
was rather exposed to reflected heat; and in 1842 it was transferred to a different 
part of the country. Two years later it was removed to Edinburgh, where I found 
it in April 1857, in the custody of Mrs Fereus, widow of the original observer 
who had begun to use it nearly 60 years before. That lady confirmed the history 
of the observations, and the fact of its being one and the same instrument which 
was used from the first. She kindly placed it at my disposal for the purpose of 
comparison.* I found it to be a spirit of wine thermometer by Kym, a very well 
known Edinburgh maker of the last century. The colour of the spirit was unim- 
paired (a circumstance very rare in modern thermometers), and the scale was of 
ivory clearly divided. Unfortunately the tube was fixed to the scale with thread 
in an insecure manner, so as to leave some uncertainty as to the precise reading. 
On a comparison with a standard thermometer, corrections to the scale readings of 
Knte’s thermometer were obtained within the limits of the monthly tempera- 
tures, and, by the aid of an interpolating curve, the following approximate cor- 
rections ascertained, which were then applied to the monthly averages calculated 
anew from Mr Ferevs’ MS. volume :— 
Corrections to Scale Readings of the Dunfermline Thermometer. 
At temp. 32 —0°5 At temp. 50 +0°6 
40 —03 55 + 0:9 
45 +01 60 +09 
* This lady died at an advanced age in the interval between the writing of this paper and its 
being read. 

