and especially in Scotland, 298 



confined to the waters of the loch, but was found on the land, 

 and at a distance of several miles from it.* It must have fal- 

 len, therefore, in the atmosphere, and was not, as some persons 

 suggested, washed into the loch from the adjoining peat-bogs. 

 A small portion of the water from Loch Earne, containing the 

 powder, having been submitted to Professor Conhell, the fol- 

 lowing note shews the result of his examination. 



" I have examined, in a general way^ the small quantity sent to me of 

 the black powder with which Loch Earne was covered. When heated 

 with access of air, it glows and is consumed, leaving a somewhat bulky, 

 but light and flocky, ash of a grey colour. This ash yields to heated 

 muriatic acid, a trace of the metallic oxide, which seems to be iron, and 

 a still feebler trace of lime, and the residue consists of siliceous-looking 

 particles. When the ignition takes place in a close tube, and lime-water 

 is introduced, it becomes very milky by agitation. It is thus evident that 

 the powder is essentially carbonaceous, with some siliceous admixture. 

 I am quite unable to offer any definite ^opinion as to the origin of such a 

 substance in such a situation. 



" After I had examined it, I got your note, asking me if I could say 

 ' that it was not soot.' The word soot, in a chemical sense, is somewhat 

 indefinite, as the nature of that substance varies according to the com- 

 bustible from which it proceeds. Thus lamp-black is almost entirely 

 carbon, whilst the soot of wood fires contains, besides combustible mat- 

 ter, certain quantities of soluble and insoluble salts. Hence, almost, any 

 fine black carbonaceous powder may he soot from some source or another; 

 and this observation might, I think, apply in the present instance, al- 

 though I should be far from saying that it was so, particularly in the ab- 

 sence of any known burning source on a large scale in the neighbourhood 

 from which it might be derived. The somewhat considerable quantity 



* The following extract from the Edinburgh Weekly Journal newspaper, 

 of date 15th February 1837, gives some further information regarding tho 

 occurrence in question, than what is in the register. " Remarkable Fact. 

 On Wednesday last (8th February) Locherne,in Perthshire, was observed lo 

 bo covered by a black scum, Avhich spread in a thin film over its surface. O n 

 Thursday morning, this had removed from tho central parts and collected 

 near the sides, where part of it Avas deposited on tho sands in the form of 

 black paste, which, when taken up in the hands, was not easily waslied off 

 again, and rendered tlie Avater (usually remarkably pure) totally unfit for use. 

 About the same time, at the farm of Miggar, eiglitor nine miles from Loch- 

 erne, some clothes that had been left out all night to bleach were next morn- 

 ing covered with black dew of a biniilar kind. AVas this phenomenon ob- 

 served in other piurts of the country, and can it have any connection with tho 

 pi*csont uoxious state of the atmospheres I" 



