THE 



EDINBURGH NEW 



PHILOSOPHICAL JOUENAL 



Analysis of the Volcanic Dust which fell in the Orkney Islands 

 ' on the 2d of September 1845. By Arthur Connell, Esq., 

 Professor of Chemistry in the University of St Andrews. 

 Communicated by the Author, 



At the time of the fall of this dust in Orkney it was 

 supposed that it had originated in an eruption of Heela in 

 Iceland; and it has now been fully ascertained that an 

 eruption of that volcano took place on the morning of 2d Sep- 

 tember, about nine o'clock,* so as to leave no doubt of the 

 justness of the conclusion. The dust had thus travelled 

 about .600 miles. Ashes proceeding from the eruption fell 

 also in the Faroe Islands on the succeeding night, and on 

 several vessels at sea on the succeeding day. 



The specimen of the ashes which was the subject of the 

 following examination, was collected by the Rev. Charles 

 Clouston, minister of Sandwick in Orkney, from the surface of 

 cabbage leaves ; and was sent to me by Professor Jameson. 



These ashes were a very fine powder of a pale brown co- 

 lour. A few insignificant black particles could be separated 

 from it by the magnet. The specific gravity of the powder 

 was found to be 2*21. 



Heated to redness on platinum-foil, it was little altered. 

 Heated in a glass-tube, it gave ofi" moisture and a very slight 

 whitish sublimate, which was partly dissolved by water, and 

 seemed to that extent to be sal-ammoniac. During the heat- 

 ing no sulphurous smell was felt, but a slight empyreumatic 



* See letter of Professor Forchammer to M. Poggendorff, AnnaUn, 

 vol. Ixvi., p. 458. 



VOL. XL. NO. LXXX.— APRIL 1846. P 



