11. August 10: 38°·50 off Hornnes, and 39° same day off Gerpir, 4 miles south of Hornnes.
12. August 19: 44° off Dalataur, entrance of Sydisfjörð.
13. August 21: 44° off Héradsflói.
14. August 22: 42° to north, with Kollumúli bearing south-west, 44° at sea.
15. September 1: 41° off Berufjörð.
The subjoined figures are the means of observations taken every fourth hour on board the “Jón Siggurðsson” steamer, in which the author voyaged (June 26 to August 5, 1872) between Hafnarfjörð and Grafarós:
| Air. | Water. | ||||
| 1. | 12° | (C.=53°·6 F.) | 10° | (C.=50° F.) | at Reykjavik. |
| 2. | 11° | (C.=51°·8 F.) | 8°·5 | (C.=47°·3 F.) | at Flatey. |
| 3. | 13° | (C.=55°·4 F.) | 9° | (C.=48°·2 F.) | at N. lat. 66°30´, W. long. (G.) 24°. |
| 4. | 9° | (C.=48°·2 F.) | 5°·8 | (C.=42°·4 F.) | at N. lat. 66°10´, W. long. 23°12´. |
| 5. | 14°·5 | (C.=58°·1 F.) | 8°·8 | (C.=47°·8 F.) | at Borðeyri. |
| 6. | 14°·5 | (C.=58°·1 F.) | 8°·3 | (C.=46°·9 F.) | at Grafarós. |
| 7. | 11° | (C.=51°·8 F.) | 6°·8 | (C.=44°·2 F.) | at Cap Nord. |
| 8. | 11° | (C.=51°·8 F.) | 8°·5 | (C.=47°·3 F.) | at N. lat. 65°8´, W. long. 23°24´. |
Both series tend to show the capricious variation of temperature (from 38° to 48° F., and from 48°·2 to 58°·1 F.), where the summer sea is subject to the influx of a little snow-water, and none of the regularity which might fairly be expected from a “gulf-stream.”
2. Every book of travels from Horrebow and Mackenzie to the present day, has given notices of the climate of Iceland.[90] The mean temperature of the Iceland year between 1828 and 1834, has been laid down at 3°·42 Reaumur (= 39°·7 F.). The annual average of Copenhagen is assumed at 46°·8 (F.); the maximum, observed in the shade, being 94°, and the minimum about 19° (F.). That of Montreal stands at 6°·30 Reaumur (= 46°·2 F.). The winters in Iceland are colder than in Montreal in October and November (both included); warmer from December to March, and again cooler from April to December. Eyjafjörð (N. lat. 65° 40´) is more genial than Cumberland House (N. lat. 53° 57´), and much warmer than any place in its own parallel. The almost nightless summers from June to August, which must affect the respiration of plants, gather caloric, and the sun at that season fails to heat only at a very obtuse angle, when the rays are intercepted by a thicker column of air. The equatorial current which prevails in occidental England for eight or nine months during the year, as the south-wester in Iceland, must greatly modify the climate. Old travellers assure us that the sub-surface is frost-bound throughout the year; this takes place only after a succession of hard winters and ungenial summers—even the cellars are rarely frozen in winter if care be taken to close the doors. Mr Vice-Consul Crowe (first Report on Iceland, 1865-66), asserts that “the average temperature of the earth is about 4½° Reaumur all the year round.”