Notes of a meteorological Tour. 11 



little cumuli formed in tlie valleys had the hills for a background, 

 and were very distinctly seen. They manifested the same pro- 

 cess as aimu'li which tonn high up over flat countries ; many 

 small ones being lo5t as if by evaporation, while the larger were 

 increased and crept up the hills and got aloft. Gentle rain came 

 on in light showers, with vvarm air. The spring begins to ap- 

 peiu. The distances were clear, and I could distinctly ken Fort 

 George as I crossed the water into Ross-shire. By comparing 

 the account of persons with whom I have conversed, 1 notice 

 the average temperature is greater here than at Ai)erdeen. 



May 6. — I noticed some nascent cumvU on the hills,, the 

 upper atmosphere being also thickly clouded. In general, to- 

 day, the clouds were higher. ' 



We travelled along the western margin of Loch Ness to 



Fort Augustus. — Showers came on in the evening, but I 

 observed that the streams of rain were formed higiier up in the 

 air than was the case yesterday morning. Walking out among 

 the moimtains at night after the rain, 1 heard the shrill cry of, 

 some waterfowl near the loch. The heron was sailing leisurely 

 over the loch as we passed along this evening, not far from the 

 Castle of Urqiihart, whose ruined towers are mouldering away 

 by degrees, and their stones rolling down the precipices into the 

 loch below. 



May 1 . — Proceeded to Fort William. I had occasion to 

 observe a range of a/muli (approaching in nature to cumulo- 

 straius) ill the valleys below Ben Nevis, and the contiguous 

 mountains extending irregularly upwards. (Some portions were 

 detached, and went up the sides of the mountain. Higher up 

 were cunudi of more scudlike and nimbiform texture ; during 

 this time it was raining, a circumstance whicli enabled me to 

 see the formation of those aascent cumuli which feed showers 

 from below during the actual falling of rain. Viewed with the 

 high hills of Ben Nevis and its range of mountains behind them 

 as a background, I could distinctly see and compare the dif- 

 ference in colour and density of these clouds and nimbiform 

 clouds higher up. I noticed too that certain flocculous masses 

 of thin clouds apparently evaporated, and the greater masses in- 

 creased, while some portions seemed attached to the tops of the 

 hills, which were comparatively clear. In the evening while 

 rowing on the water, 1 saw the clouds rolling along much below- 

 very low hills, while others which sat upon higher ones had fine 

 cumulous tops, and a nimbiform or dense wanecloud nnich higher 

 up moved off with the direction of the wind and left a dingy 

 horizon ut sunset. I found ascending to the to|,' of Ben Nevis 

 <[uite impossible from the depth of snow. Herring gulls flying 

 in flocks about the water, Air mild. S|uing advancing. By 



night 



