9 187 



into a white mist, from the hot water of the springs. In the illustration, which is 

 taken from the north, the swimming-bath is seen farthest away, Hornahver in the 

 middle, and Bæjarlaug in the foreground. The farm is not shown in the plioto- 

 graph, as it lies nearer and more to the right. The picturesque mountains to the 

 south-west, Mœlifellslinji'ikur (and others) are invisible also, as they were enveloped 

 in mist. We also tested the gases, whilst staying at this spot, from two more 

 distant springs. Reijkir No. 4 is from Fosshver, a little spring near Ihe beautiful 

 waterfall Reijkjafoss, two kilometres to the north of Reykir. Here hot water gushes 

 up through rifts in the rocky conglomerate on the eastern bank of Svartâ. The 

 water has a temperature of (Sir, and there are very active gaseous exhalations. 

 Reykir No. 5 is from Skidastadalaug, situated on the other side of Svarta, about a 

 kilometre to the west of Reykir ; hot water issues from three places here at a tem- 

 perature of 67" to OS . There is a considerable volume of water. The peculiarity 

 of this spring is that there are apparently no gaseous exhalations from the spring 

 itself But gases are emitted through a little pool 1 ni. west of the most southerly 

 spring. The temperature in this pool was 17.3" C; at the same time the tempera- 

 ture of the air was only 4" C. The sample gas which was examined comes from 

 this place. 



A fact which characterises all the springs explored at Reykir is that the 

 water shows a weak alkaline reaction. The spring water also contains chlorides 

 and carbonates, and sulphates to some small extent. 



Hveravellir. 



Hveravellir is situated in a hollow by the northern border of the great field 

 of lava called Kjalhraiin. According to the altitude taken by the barometer, lire 

 place where we pitched our tent was 635 m. over sea-level; fjoBv. Thoroddsen 

 made it 632 m., very near to our estimate. 



Among previous descriptions of the springs at Hveravellir, the following are 

 noteworthy: — '"Reise gennem Island", vol. H, pp. 637 — 639, by Eggert Olafsson 

 and Bjarni Palsson, 1752 ; "Iceland, the Journal of a Residence in that Island during 

 the years 1SU and 1815", vol. H, pp. 203-209, by E. Henderson. 



But the most exhaustive description of the springs at Hveravellir is by pOR- 

 VALDUR Thoroddsen ', who stayed at Hveravellir from the 24th to the 26th August 1888, 

 made a map of the neighbouring spring district, and enumerated the most impor- 

 tant springs. Apart from the more detailed examination of the composition of the 

 gases, our efforts in this locality were chiefly confined to ascertain what changes 

 the springs had undergone since Thoroddsen explored them in 1888. As a basis 

 for this investigation, it is necessary to use Thoroddsen's map, which is therefore 

 reproduced here (Fig. 3). 



The springs are situated on two dome-shaped silicious sinters. The sinter to 

 the north-west is the less prominent, and most of the springs are insignificant in 



' Ymer, 1889, p. 49; and Geogr. Tidsskrift 10, 2li, 1889—1890. 



D. K D. ViJensk. SelsU. Skr., 7. IliL-klie, n:iturvidensk. og niathem. Afil. VIM. 4. 25 



