J. D. Dana — History of the Mt. Loa Summit Crater. 15 



II. MOKUAWEOWEO, THE SUMMIT CRATER OF 



MT. LOA. 



Maps. — A map of the island of Hawaii, reduced from the 

 Government map, is here introduced (Plate 1) for the "better 

 illustration of the facts and discussions beyond.* It shows 

 the topographic simplicity of the island — a fact not expressed 

 in most of the small published maps, which generally (like 

 that of the eleventh volume of the new Encyclopedia Brit- 

 tanica) put in mountain ranges or ridges that do not exist. 

 The map will enable the reader to appreciate the relative posi- 

 tion of Kilauea and the Mt. Loa crater, their relative heights, 

 the absence of water-courses from all of the mountain slopes 

 except a small windward region ; the large size of the valleys 

 of the Kohala Mountains to the north ; the positions of the 

 great lava streams of 1840 to 1887 ; the routes of the roads 

 (mostly bridle paths) ; the two routes to Kilauea, one of thirty- 

 one miles on horseback from Hilo, the other of about half this 

 distance, from Keauhou, the upper half a good carriage road ; 

 and also the districts into which the island is divided, and the 

 positions of the principal villages. 



The present form of the summit crater, Mokuaweoweo, is 

 shown on the map by J. M. Alexander, Plate 2, reduced from 

 the results of his survey. The height of the highest point, 

 given on it, 13,675 feet, differs eighty-five feet from Wilkes's 

 determination of the same point in 184:1. 



The history of the summit crater is mostly a history of the 

 results of its eruptions, for few facts have been observed about 

 the action within the crater. It has excited attention when an 

 eruption has been in progress; but the chief outflows have 

 begun below the summit and the source of the outflow is 

 usually the only place reached. Still there is much to be 

 gathered from the reported facts. My personal investigations 

 have been confined to the base of the mountain, and the re- 

 view beyond is hence almost solely from the accounts of others. 



History of the Eruptions from 1832 to 1888. 



1832, June 20.— On the 20th of June, 1832, according to 

 Hev. Joseph Goodrich, lavas were discharged from several 

 vents about the summit. The fires continued to be visible for 

 two or three weeks, and were seen from Lahaina, 100 miles to 

 the northwest. Nothing is known of any large discharge of 

 lavas, and no mention is made of accompanying earthquakes. 



*The Government map, as stated upon it, is only a preliminary map, part of 

 the survey being still incomplete. 



f Goodrich, this Journ., xxv, 201, 1834, letter of Nov. 17, 1832. 



