312 Rev. Mr Mac vicar on a Meteorological Phenomenon 



Silicate of Zinc, Bohemia. — This mineral is crystallized. 

 Alone in the matrass, it turns opaque, and thickens in the di- 

 rection of the cleavage ; gives no trace of carbonic acid, but a 

 slight trace of water with salt of phosphorus ; decomposes 

 with difficulty, and leaves a skeleton of silica full of bubbles ; 

 with borax and soda, it comports itself in the same manner as 

 the siliceo-carbonate ; with solution of cobalt, it affords a 

 greenish blue colour. This is consequently a true silicate of 

 zinc with a little water of crystallization. 



Art. XX. — Account of a Meteorological Phenomenon, which 

 zvas observed at the Summit of Ben-Nevis on the 21th June 

 last.* By the Rev. John Macvicar, Dundee. In a letter 

 to Dr Brewster. 



Dear Sir, 

 In consequence of the suggestion of Professor Hooker, I 

 send you an account, as circumstantial as my notes and re- 

 collection admit, of a meteorological phenomenon, which 

 was observed at the summit of Ben-Nevis on the 27th June 

 last. 



The weather, for some days previous, was extremely rainy 

 and disagreeable ; for the temperature was low, and the rain 

 was accompanied with a fog and a fresh breeze of wind. On 

 Saturday morning, however, the rain ceased, and the clouds 

 hung in the atmosphere in the form of immense cumuli and 

 cumulostrati. The nimbus also was seen in various quarters, 

 and before mid-day, the district of Ben Nevis was visited by 

 one of these clouds, which poured rain almost without inter- 

 ruption, during the greater part of the day. About 2000 

 feet of the altitude of the mountain were immersed in the 

 cloud ; and from the observations of those who ascended to 

 the summit, it appears that this was not much less than its 

 general thickness, for they frequently saw its upper surface. 

 On Sunday, the weather improved ; and, on the morning of 

 Monday the 27th, it was still better, though it was not yet 



* Phenomena, bearing; some analogy to the very interesting one de- 

 scribed in rhis paper, will be found in the Edinburgh Encyclopwdia, Art. 

 Electricity, vol. viii. p. 491. — Ed. 



