NOTES ON THE lQl6 ERUPTION OF MAUN A LOA 331 



marked illumination, which we may designate as the primary glow, 

 was most brilliant at the fountainhead, and above the front of this 

 flow (where its outflashing was augmented by the light from the 

 burning forest) ; but also above the course of the flow between its 

 front and source the glow was much brighter than the general sky 

 glare. This formed a band of primary illumination whose length, 

 as seen from the gate about a mile west of the ranch house at 

 Kahuku, was very close to seven miles; and its brilliantly lighted 

 arch rose about three-quarters of a mile above the mountain profile 

 (Plate III, c). 



A diffuse red glow covered the sky everywhere and, in early 

 evening, low-lying cloud and fog banks clinging to the mountain 

 slopes below the road, and illumined dimly by reflections from the 

 cloud layer above, led to a current erroneous opinion that the 

 flow already had advanced down the slope beyond the road in 

 Kona. 



Owing to the wretched state of the road surface, a serious con- 

 gestion of motor traffic (some 250 motors headed westward and 

 about 80 headed southward, toward a meeting-point near Hono- 

 malino, on a road too narrow for passing or turning except at 

 widely separated places), and much uncertainty as to the exact 

 course, rate, and behavior of the flow, the writer spent most of the 

 night at a gate on the road about a mile west of Kahuku, where 

 he returned after going to within three to four miles of a group 

 of houses at Honomalino which stood in the apparent path of 

 the flow. 



The photograph (Plate III, c 1 ) shows the scene from this station 

 as it appeared just before midnight, May 22. In this view, of 

 course, the bright reddish glow which covered all the sky does not 

 appear, but simply the brilliant arch of the primary illumination, 

 as designated above. During the night the following changes were 

 observed: 



A little after midnight there was noticed a rapid spread of very 

 brilliant glow to the right of the fume column rising at the fountain- 

 head. This was a conspicuous feature of the action until after 

 1 too a.m. It was thought to indicate a flow toward Kahuku. This 



1 Made on a Wratten Panchromatic M plate exposed 30 minutes at//6.3. 



