F. A. Ferret — Lava Fountains of Kilauea. 141 



level. The result of this is a general in-surging of surface 

 lava from all sides and a considerable down-flow where the 

 fountain lava sank. In the case of a large fountain appearing 

 at frequent intervals in the same place there may be a practi- 

 cally continuous surging thereto of surface lava whose down- 

 flow will then form a part of the lake's circulatory system. 

 This is especially the case with the peripheral fountains, but 

 the subject of circulation is to be treated specifically in a 



Fig. 2. 



Fig. 2. Telephoto night view. " Old Faithful." Spatter phase. 



future paper and this phase is here referred to merely as a 

 direct effect of fountain action. 



The noble proportions of the surroundings and the consid- 

 erable distance from the eye of the observer unite in giving 

 an impression of the size of the fountains which is far below 

 the reality. For visual observation a good glass is essential, 

 but the rapidity of motion renders photography a more satis- 

 factory means of study, providing an image of sufficient size can 

 be obtained with a short exposure. For this purpose the writer 

 employed a Zeiss a Magnar" telephoto equipment having an 

 equivalent focal length of 80 cin with a working aperture of 

 F. 10. At an average distance of 200 meters the photographic 

 images of the fountain domes were 5 cm in breadth, which gives 

 to the fountains a diameter of fully 12 meters. 



