VULCANISM, ETC., IN ICELAND. 507 



1729. The LeirhniiJcr again became active on the 30th of January, 

 and eruptions took place during the entire year. The lava advanced 

 to the lake Myvatn and demolished the presbytery of Reykjalidh, 

 together with three other buildings. One current emptied itself into 

 the lake and a terrible combat took place between the elements. 



1732. Earthquakes at Rangdrvellir and at Eystrihreppr, on the 7th of 

 September, by which forty farm buildings were more or less damaged 

 and eleven or twelve nearly overthrown. These shocks continued dur- 

 ing two weeks. 



1734. Earthquake shocks at Floi and other localities in Arnessyssel, 

 by which thirty farm buildings were overthrown, sixty to seventy 

 damaged, and seven or eight people killed. 



1749. Earthquakes at Olfus and Borgarfjordhr; the flow of the hot 

 spring of Skrifla diminished and the farm-house of Hjalli, at Olfus, to- 

 gether with the church, sank 1.25 meters below the surface. 



1752. Earthquake in Arnessyssel; 12 farms in Olfus damaged, and 

 one church overthrown. 



1753. Eruption in the vicinity of Sedhujokfll. A "Jokellob" pro- 

 duced in the river Djupd, which flows in a gorge towards the presby- 

 tery of Kdlfafell, a rise of 60 meters; an inundation followed which 

 devastated the entire surrounding country. The waters of the Skaptd 

 and of the Hverfisfljot rose proportionate]}". The ashes were carried 

 beyond Skaptdrtunga. 



1754. Volcanic phenomena of three hours' duration in the lava beds 

 west of the Hecla. 



1755. Sixteenth eruption of Katla, preceded in the north by violent 

 shocks of earthquake, overthrowing 13 farm-houses situated mostly 

 in the neighborhood of Hiisavik, and lasting from the 10th to the 16th 

 September. The eruption commenced on the 17th October and lasted 

 until August, 1756. The "Jokellob" and the ashes, which were carried 

 as far as Leird, in the Borgarfjordhr, to the west, and to Djupivogr to 

 the east, occasioned great damages. A large part of Skajitafellssyssel 

 was covered with a layer of ashes 15 to 20 centimeters in thickness, 

 and fifty farms had to be abandoned. In consequence of this eruption 

 two ridges were formed on the Myralssandr, 23,000 meters loug, 40 

 meters high, and composed of ice, pumice stone, mud, and ashes. 



1766. Seventeenth eruption of Hecla, commencing on the 5th of 

 April, as ordinarily with heavy earthquake shocks, perceptible south- 

 westward as far as Reykjanes. The ashes drifted northwest and 

 caused darkness in the north of Iceland ; the layer of ashes formed was 

 60 centimeters thick in the vicinity of the volcano, and 30 centimeters 

 at 225 kilometers distant, but fortunately it fell mostly in uninhabited 

 districts. Pieces of pumice stone of 2 meters circumference were 

 thrown a distance of 15 kilometers, a piece of lava of 1,750 grains a 

 distance of 23 kilometers, and another piece of 3,750 grains weighty 



