and especially in Scotland. 147 



on which I observed it on Loch Earn, was also very calm in 

 the morning, attended with a thick haze on the Loch. 



*• Should I hear or see any more of the powder in any shape 

 I shall endeavour to procure it, and send it to you. 



" I happened, unfortunately, to be at Perth on the 30th July, 

 and was not myself sensible of the shock on that day. It was 

 distinctly felt here ; but it was not so severe as the shock in 

 October 1839, although all concur in saying that it continued 

 longer. Some describe the sound as appearing to have 

 travelled from south-west to north-east. I would be inclined 

 to infer also, from the accounts I have received from different 

 persons, that this one was more severely felt on the higher 

 situations than on the lower. ^^ 



One of the bottles mentioned in Mr Stewart's first letter, 

 containing the powder from Loch Voil, was given to Professor 

 Traill for chemical analysis. His report is in the following 

 letter : — 



" 10 Albyn Place, I2th August 1841. 



" My Dear Sir, — On carefully evaporating, by a gentle heat, 

 eight fluid ounces of the water of the loch, it left behind 

 a black residuum, which, when thoroughly dried, weighed 

 4.48 grains — so that each English pint may be considered 

 as containing nine grains of black matter. This, when che- 

 mically examined, appeared to consist chiefly of carbon, 

 with minute portions of argil and silica, and, I think, a trace 

 of iron ; but having mislaid the note of the relative quanti- 

 ties, I am unable to give them accurately — and I intend, early 

 next winter, to repeat the analysis, if I do not recover my 

 notes. 



*' The black matter is in a state of extremely minute division, 

 for it took several months entirely to subside, leaving the 

 water of a very pale wine colour, and transparent. The black 

 matter attached itself to the sides of the containing glass- vessel, 

 so as to give the contained fluid an inky hue. The greatest 

 portion had subsided to the bottom, and the fluid itself was of 

 the colour above mentioned when drawn ofl'. 



*' The origin of this dark matter is rather puzzling. Were it 

 only seen after heavy rains, it might be supposed owing to 



