272 Scientific Intelligence. 
with plates, on the coal basins of Bességes and Alais. M. J. de Malbos 
read a memoir on a fossil plant of the green sand, before found in 
other formations by MM. Faujas de Saint Fond and Dunoyer. 
2nd of September was occupied by a continuation of the coal explo- 
rations. ‘The 3d was devoted to an examination of the lacustrine 
Hyppolyte-de-Caton, Euzet; a marly limestone, in the lower part con- 
tains menilites, fossil fish, insects and vegetables. 
7. Volcanic Dust. of Hecla; by Dr. Trait, (Proce. Roy. Soc., 
Edinb., ii, 56, Dec. 1845.)—Dr. Traill read an account of dust falling 
from the atmosphere on the 2d and 3d of September last, in the islands 
of Orkney. 
_ This dust was observed by a gentleman in the island of Rousay, fall- 
ing from the air on the morning of the 2d. It was collected by another 
at Skaill, on the western shores of Pomona, on the morning of the 3d; 
and by two other gentlemen in Kirkwall on the same day. 
also to have fallen in several other parts of Orkney, probably over all 
the islands; and was observed also to reach the northern coasts of 
Caithness, within an area of which the radius cannot be less than 30 or 
miles. 
It covered, to the depth of from +4; to 2 inch, linen laid out to dry, 
glass frames in gardens, and the leaves of plants of every kind, with a 
and grinding between the teeth. It does not effervesce with acids, 
and consisted chiefly of silex, alumina, oxyd of iron, with a trace of 
lime. ‘ 
This dust bears much resemblance in composition and appearance to 
that which covered the decks and rigging of vessels in the West Indian 
seas, when the eruption of the Soufriére took place in St. Vincent, in 
1812. Those who collected the dust in Orkney, state the probability 
that it proceeded from some eruption of Hecla, as the ashes of that 
volcano once before fell in Orkney ; and the wind for several days be- 
fore the 2d of September had blown strongly from the N. W. 
‘he truth is, that such an occurrence has at least three times before 
calamitous which ever happened in Iceland. 
Thus, the volcanic ashes of that island have thrice before reached 
our northern islands ; and recent intelligence brought by Danish fishing 
vessels from Iceland announces, that, in the end of August, after being 
quiescent since 1766, Hecla has emitted a violent eruption from 1s 
flanks ; and there can be little doubt that the dust now exhibited is de- 
rived from that eruption. 
distance between Hecla and the Orkney Islands is about 550 
miles. Volney and other writers assure us that the ashes of Etna are 
often carried to the plains of Egypt, or to double that distance ; 
