506 SCIENTIFIC RECORD FOR 1885 



1716. Erux)tion iu the vicinity of lake Grimsvatn. 



1717. Eruption of the Kvtrlcjjall ou the 17th of September. A large 

 portion of the country, to the north and east, was covered with ashes, 

 and the Jokuls4 i Axarfirdhi carried to the sea large quantities of 

 pumice stone. 



1721. Ninth eruption of Eatla, commencing on the 11th of May with 

 a great " Jokellob." The blocks of ice carried clown to the sea, and till- 

 ing it to a depth of from 130 to 150 meters, formed a barrier to a dis- 

 tance of three nautical miles from the shore. A turf-covered ridge of 

 rock of about 24,000 square meters was cut awaj" on being struck with 

 this giant force. A rocky pinnacle of 38 meters in height was also 

 carried away, and the large cavern of Skipahellir comi)letely filled up 

 with gravel. The wind carried the ashes to the west ; and at Saurbaer, 

 .upon the Hvalfjardharstrond, 150 kilometers distant, the darkness was 

 so intense as to prevent, at broad noon, the distinguishing of letters in 

 a book. The sailors of Reykjanes, 188 kilometers from the Katla, were 

 barely able to find the entrance of the harbor at the beginning of the 

 eruption. It lasted during the summer and fall. 



1724-'30. During this period several eruptions took place in the 

 vicinity of lake M^vatn. 



1724. Eruption of the Krafia, 17th of May. The crater of Viti, on the 

 west slope of the mountains, emitted an enormous quantity of ashes, 

 and to the east of lake My vatn it formed a bank 1 meter deep. The 

 shocks were felt throughout the entire couutryj houses were over- 

 thrown, and the contour of the country changed by the formation of 

 elevations and depressions. 



1725. January 11, eruption of Leirhnukr, with much shaking of the 

 earth, and on April 19 eruption of Bjarnarfiag. The earthquakes, 

 increasing in force, attained their maximum intensity on the 8th of 

 September. In the same year an eruption of Skeidhardrjokull took 

 place. 



1727. Eruption of OraefajoJcull, lasting from the 3d of August, 1727, 

 until the 25th of May, 1728. Powerful "Jokellob" devastated the 

 entire country below the mountains, and carried out into the sea a large 

 number of horses and other animals. The Skeidhardrjokull was, at the 

 same time, much agitated. On the 21st of August another eruption 

 took place from the Leirhmikr, throwing out a current of lava, which 

 took a northerly direction. 



1718. Eruption of the Leirhmikr, at 2 a. m. of the 18th of April, with 

 a flow of lava, which almost reached lake My vatn. Four hours later 

 a new crater opened to the south of Leirhuukr, iu the Hrossadalr, and 

 at about the same moment the Bjarnarflag erupted. Two days later a 

 crater, situated on the east slope of the Dal/jail, near the Beykjahli- 

 dharsel, emitted a large current of lava. Ou the 18th December another 

 eruption of the Leirhmikr. In the same year several volcanic phe- 

 nomena were observed in the lava beds of Recta. 



