Prof. Nor densUold— Transport of Volcanic Dud. 295 



in spots ; in the neighbouring Justedalen a fine dust, though in small 

 quantity, had fallen during a whole week, the greatest quantity on 



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the night before the 30th, and at Alesund 17 grammes ol ashes had 

 been collected on a square metre. 



In the neighbourhood of Torghatten, the ashes which fell the 

 29th March and the preceding twenty-four hours would form a bed 

 three lines thick, and here it is even said that the clouds of ashes 

 darkened the day, and made the night uncommonly dark. 



Similar accounts are given in Numedalen and Eomsdalen, in 

 Trondhjem, at Lofoden, etc. The ash-rain of the 29th and 30th 

 March did not extend to the most northerly part of Norway, while 

 on the other hand the snow and ice at Eamsfjord, near Tromso, was 

 found on the 14th March to be strewn over with a dark layer of 

 dust. The southern boundary of the territory of the fall in question 

 is thought to have lain north of Gothenburg, where the owner of 

 extensive carefully kept greenhouses caused special inquiries to be 

 made whether anything unusual had been seen upon the glass, and 

 when he obtained a negative answer, further collected similar in- 

 formation from the surrounding region with the same result. Also 



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from Husquarna, near Jonkoping, Amot, Kongsvinger, and Abo, 

 distinct statements were received that at these places no noticeable 

 fall of ashes took place. It may also be stated with considerable 

 certainty that no fall of ashes happened in eastern Sweden during 

 the period from November, 1874, to March, 1875, because the Assistant 

 in Meteorology at Upsala, Hildebrandson, caused the remainder of 

 melted snow from every more considerable snowfall during this 

 time at Upsala to be preserved; and this remainder has been found 

 to contain common sand, remains of organic substances, iron, and 

 traces of cobalt, but none of the easily recognizable, porous, glass- 

 like particles which distinguish the Haga dust. 



Samples of the fallen dust have been received from most of the 

 places mentioned above, and it has shown itself under the microscope 

 to be of quite the same kind and the same fineness as the newly 

 described dust from Haga, that is, it consists of a fine angular pumice 

 dust, which is neither rounded oif in the smallest degree by being 

 rubbed together in water, nor consists of smooth round glassy 

 particles formed directly by the cooling of lava finely distributed in 

 the form of drops or vapour. 



The volcanic ashes which have fallen in Scandinavia possibly 

 consist of a pumice sand, which in the course of time has collected 

 in the crater opening or in cavities and passages in the interior of 

 the volcanos, until, on the occasion of an eruption and under the 

 action of superheated watery vapours, a violent cleansing has taken 

 place, and the dust which has been collected during the course of 

 many years has been thrown high into the air, to be afterwards 

 spread by the wind to remote countries. 



But even in this case some rubbing at least ought to be ob- 

 servable on the projecting sharp angles of the grains, and some 

 chemical erosion to have taken place on their smooth surfaces. We 

 should besides have expected to find among the inorganic constituents 



