24 J. D. Dana — History of the Changes in Kilauea. 



Merritt and myself) that Captain Wilkes in his visit to " all the 

 stations around the crater in their turn " (xxxiii, 451), on reach- 

 ing the high Uwekahuna summit, instead of relying on his angles, 

 probably took the shorter way of sketching in the ridges that 

 stood to the southeast and south ; and that he was led by insuffi- 

 cient topographical judgment to throw the wall, together with 

 the parallel ridge outside of it, too far to the eastward. The error, 

 as we saw when thei*e, is an easy one for him to have made. This 

 cramped the map to the southward about the Great South Lakes, 

 but the angles taken from other stations were not enough to serve 

 for the needed correction and the sketching was allowed to con- 

 trol the lines. However this may be, it is lamentable that a cor- 

 rect map, with a careful determination of heights around the 

 crater, was not made in 1840. 



An important error also exists in Wilkes's determination of the 

 longitude of his encampment near the crater. The Surveyor- 

 General of the Islands, Prof. Alexander, informed me that the 

 position Wilkes gives Kilauea is 8-| minutes too far west; and 

 that the error affects all the southeastern quarter of his map of 

 Hawaii including the position of the coast line. His longitude of 

 the summit of Mt. Loa is correct. 



Mr. Brigham 's mo.p. — Mr. Brigham's inap is a register of 

 the facts of 1864-65, a period just half way between 1841 and 

 1887. It indicates unfinished changes in progress within the 

 crater which were commenced in 1840, and other conditions 

 that became pronounced only in later years. 



