508 



DR BUCHAN ON THE 



Hourly Observations at the two Observatories on 29th September 1895 are shoion in the following Table, when the 

 difference of their Temperatures teas small. Barometric Differences are expressed in thousandths of an inch. 





Barometer at 3" 

 Sea Level 



2° and 



Temperature. 



Hygrometer 



Depi^sion of 



Wet Bulb. 



Sunshine. 



Rain. 



Wind 

 0—12. 



Fort- 



Ben 



Differ- 



Fort- 



Ben 



Mean. 



Differ- 



Fort- 



Ben 



Fort- 



Ben 



Fort- 



Ben 



Ben 





William. 



Nevis. 



ence. 



William. 



Nevis. 



ence. 



William. 



Nevis. 



William. 



Nevis. 



William. 



Nevis. 



Nevis. 





Ins. 



Ins. 



Ins. 















Hrs. 



Hrs. 



Ins. 



Ins. 



Dir'n.Foice. 



1 A.M. 



30-259 



30-319 



+ 60 



53-2 



51-7 



52-5 



— °l-5 



°1 



5°2 











SW 2 



2 „ 



•248 



■308 



+ 60 



52-5 



52-7 



52-6 



+ -2 



•2 



5-9 











WSW1-2 



3 „ 



•248 



•303 



+ 55 



52-6 



51-8 



52-2 



— -8 



•2 



5-1 











SW 1 



4 „ 



•237 



•300 



+ 63 



51-6 



51-6 



51-6 



— -o 



•1 



5-0 











SW 1 



5 ,, 



•233 



•298 



+ 65 



51-2 



51-2 



51-2 



— -o 



•1 



4-9 











SW 1 



6 „ 



•238 



•304 



+ 66 



50-1 



50-7 



50-4 



+ -6 



•2 



5-3 











sw o-i 



7 ,, 



30-244 



30-312 



+ 68 



49-1 



51-9 



50-5 



+ 2-8 



•4 



5-9 







•24 







SSW 1 



8 „ 



•241 



•300 



+ 59 



49-7 



53-2 



51-5 



+ 3-5 



•4 



5-7 



•40 



1-00 







S 1 



9 „ 



•242 



■288 



+ 46 



53'5 



55-0 



54-3 



+ 1-5 



•8 



6-7 



1-00 



1-00 







S 1 



10 „ 



•229 



•263 



+ 34 



56-4 



55-5 



56-0 



— -9 



"7 



5-0 



1-00 



1-00 







S 1 



11 ,. 



•220 



•249 



+ 29 



59-0 



56-5 



57-8 



— 2-5 



1-0 



5-5 



1-00 



1-00 







S 1-2 



Noon 



•214 



•227 



+ 13 



62-8 



57-5 



60-2 



— 5-3 



2-6 



5-5 



1-00 



1-00 







S 0-2 



1 P.M. 



30-188 



30-220 



+ 32 



63-2 



57-5 



60-4 



- 57 



2-5 



4-9 



1-00 



1-00 







SSW 1 



2 „ 



•171 



•197 



+ 26 



64-8 



57-3 



61-1 



— 7-5 



3-6 



4-0 



1-00 



1-00 







SW 1-2 



3 ,, 



•160 



•181 



+ 22 



66-5 



57 4 



62-0 



— 9-1 



4-2 



5-2 



1-00 



1-00 







SW 2-3 



4 ,, 



•156 



•184 



+ 28 



67-0 



56 2 



61*6 



—10-8 



4-1 



5-3 



1-00 



1-00 







SW 1-2 



5 „ 



•154 



•193 



+ 39 



65-5 



55-4 



60-5 



—10-1 



2-9 



5-1 



•20 



•87 







SW 1-2 



6 ,, 



•156 



•197 



+ 41 



62-8 



53-9 



58-4 



— 8-9 



1-7 



2-8 











SW 1-2 



7 „ 



30-165 



30-212 



+ 47 



62-3 



53-2 



57 8 



— 9-1 



1-6 



3-2 











SW 1 



8 „ 



•164 



•211 



+ 47 



61-5 



52-8 



57-2 



- 8-7 



1-5 



2-0 







• • • 





SW 1-2 



9 ,, 



•163 



•210 



+ 47 



60-0 



52-6 



56-3 



— 7-4 



1-2 



2-3 











SW 2 



10 ,, 



•156 



•213 



+ 57 



57-3 



51-9 



54-6 



— 5-4 



•6 



2-0 











S 2-:i 



11 ,. 



•152 



•217 



+ 65 



56-0 



51-2 



53-6 



— 4-8 



•3 



1-2 











SSW 2 



Mid. 



•146 



•208 



+ 62 



54-9 



51 



53-0 



— 3-9 



•5 



•7 











S 1-2 





30-199 



30-246 



+ 47 



57-6 



53-7 



55-7 



— 3-9 



1-3 



5-3 



8-62 



10-11 



o-oo 



o-oo 



1-4 



No cloud at both stations. 



The results of the observations at the Ben Nevis Observatories soon familiarised us 

 with the fact that during anticyclones the air at the top of the mountain is very dry, 

 and for the height ve^ warm, so that the normal difference of the daily mean 

 temperatures, 15°*4, no longer holds good. On this day the difference was small, the 

 mean at Fort-William being 57"'6, and at the top 53°"7, or only 3°"9 lower. Indeed 

 for several hours in the morning the temperature at the top was higher than at Fort- 

 William ; and at 8 a.m., while the temperature at Fort- William was 49° - 7, at the top it 

 was 53°'2, or 3°'5 higher. 



It is seen that on this day, while at the top of the mountain temperature was very 

 high, and the air very clear and dry, at Fort- William, with a sky equally clear and 

 temperature high, the air showed a large humidity, being in truth near the point of 

 saturation before 10 a.m. and after 10 p.m. ; and it maybe added that, as observed, this 

 condition of large humidity extended to a height of about 2000 feet, or about halfway 

 to the summit. Thus, while the barometer at the top was under an atmosphere 

 wholly anticyclonic, with its accompanying dry dense air, the barometer at Fort- William 

 was not so circumstanced ; but instead it was under the pressure of such dry dense air 



