316 Mr Haidingers Description of Edingtonite, 



lightning, the course of which through the air, could be dis- 

 tinctly traced. 



The thunder storm of the 27th June, came from the south- 

 east, and seems to have had a very wide range. Fortunately 

 its force was nearly spent before it reached the highest point 

 of Scotland ; otherwise, instead of witnessing it in an 

 evanescent state, perhaps we might have afforded a melan- 

 choly decision of the question, whether lightning ascending 

 into the clouds, is equally fatal to the objects it leaves, as the 

 descending fluid is to those which it strikes. 



In the afternoon the weather cleared up. Most of the 

 clouds evaporated, leaving the fine sky. The sun shone very 

 bright, and the evening became very warm. Three hours 

 ago, on the top of the mountain, we had been chilled by cold 

 and covered with snow ; and now, in the valley below, we 

 could look up with admiration to its cloudless summit, in a 

 climate where we were severely bit by the Tabanus caecutiens. 

 The following day was very fine, and during the greater part 

 there was not a cloud to be observed in the atmosphere. 

 I am, Dear Sir, yours sincerely and respectfully, 



John Macvicar. 

 Dundee, September 10, 1825. 



Art. XXI. — Description of Edingtonite, a New Mineral 

 Species. By William Haidinger, Esq. F. R. S. E. 

 With an Analysis by Edward Turner, M. D. F. R. S. E. 

 &c. Lecturer on Chemistry, and Fellow of the Royal College 

 of Physicians, Edinburgh. Communicated by the Author. 



Form pyramidal. Fundamental form, an isosceles four-sided 

 pyramid of 121° 40', and 87° 19' = P. Plate VII, Fig 9. 



a - ^0.905. 



Simple forms. P— 2 (n) = 144° 38' ; P (P) ; P+o> (m). 



Character of combinations. Hemi-pyramidal, with parallel 



faces . E=? = 129° 8', 35° 22'. Fig. 10. | = 92° 41', 58" 



20'. Fig. 11. 



Combinations observed similar to Fig. 12, consisting of all 



