11 



189 



comparison lo those on the south-easterly dome. In order to identify each parti- 

 cular spring, we measured with a line the distances hetween the s])rings on the 

 north-western dome. The position of the springs in the south-eastern group was 

 arrived al hy measuring the distance from a given hase. In making this survey 

 we used a une and optical square. On the basis of these measurements I have 

 made the accompanying map, which shows the relative distances of the springs in 

 the two groups (Fig. 4j. The relative position of the two groups, and the hearings, 



Ce 



. N / 



27 a 



CJ_, Oshiirholl 

 Blnhiyr 



^ ; 



Tenl ; 





015 



•I -- Fannhrrr 



^ , Pjj^'Brœàrahverir 



SS ^ m 

 I 



/6 



Gainli 

 .<!ro/:l,i;r 







.20 



}?2 

 9-21 



/S 



Zi 



-If) 



1/ 



*26 



/Z 





^/ 



in ZO 30 'fO 50 60 10 80 90 WO metres 



Fig. 4. 



are taken from Thoroddsen's map, as these were not ascertained by direct obser- 

 vation. On comparing this map wilh Thoroddsen's, there are several points of 

 disagreement, both in the relative position of the springs and in the distances 

 between them. 



These deviations, which can hardly be caused by changes in the position of 

 the springs, but must naturally be put down to the inaccuracy of the maps, are 

 nevertheless not of such a nature, as to cause doubt as to the identity of the 

 respective springs. On the other hand, if we compare Thoroddsen's description of 

 each particular spring with our observations, they will be found to be, in all the 



