At Næfrholt.
July 13.
Ascended Hekla.
Left Næfrholt 8.25 A.M.
Rode down the turf lane; crossed the dwarf stream (lavapés), up right grassy bank, and crossed again. Entered basin of “Unknown Lake”—thin strip of flat land with holes often marked by grass and willows. All “sinks” (sink-holes) and punchbowls, as if limestone country. Last thick vegetation 1500 feet high. Then into dreary region, sand and cinder; powdery red cone of fine cinder on left. Slabs of heat-altered trachyte. Obsidian of two kinds—(1.) Huge blocks of pitchstone found from top to bottom of cone, hard and flinty (Hrafntinnu proper); and (2.) Small pieces of “Samidin,” or obsidian with crystals of white jasper like that of Tenerife and other places. Bombs showed furious cannonade. Palagonite everywhere in situ and in scatters: some contained obsidian.
Made for big, rough lava-stream, rusty and in heaps; in places rapidly degrading, and leaving only core. Ponies sank to fetlock. Hugged left of Steiná (stone stream). After two hours’ ride, at 10.30 A.M. crossed hill, reached barren divide too steep for horses.
Aneroid in air, 28·18 (difference, 2·06); thermometer, 92° (in pocket); hygrometer, 2°.
Walked up slope of divide; descended very short pitch of stone and débris, steepest bit of whole march. Crossed vein of lava (Sept. 2, 1845) like pulled bread, all slag and clinker; pulverising above. Reached a kind of couloir, a rim on left of lava-stream. Black sand and two large tongues of ice-based snow, white and brown, ridged with dirty earth, and dotted with dwarf ice-tables, sable above and ermine below. More ice as we ascended, keeping on the earthy parts. Many halts.
12.20.—Reached crater of 1845. Observed instruments.
Aneroid in air, 26·33 (difference, 3·90); thermometer, 83° (in pocket).