J. D. Dana — History of the Changes in Kilauea. 213 



A specimen of the copper slag from the old " Revere Copper 

 Works' 7 in Massachusetts, obtained through the kindness of 

 Dr. Wadsworth, is microscopically and chemically nearly iden- 

 tical with the so-called meteorite. That it is not of meteoric 

 origin thus seems to be settled, but notwithstanding the most 

 positive stories are told about " seeing it fall," " getting pieces 

 while still hot," etc., I have not been able to trace all such 

 stories down. In regard to one of them I learned from the 

 tinder of a fragment which came into my hands that "in 

 1850, while standing upon the shore at Northport in the 

 evening, suddenly the region was lighted and a ball of fire 

 passed over his head from west to east, fell into the water and 

 exploded with a loud noise." Failing to find any fragments 

 he concluded that it struck too far out. In 1881, having heard 

 that pieces of a meteor had been found there, he revisited the 

 spot and at dead low water picked up several, one of which I 

 have. Although the pieces he found were probably old copper 

 slag brought by some vessel in ballast, still the fall of a meteor 

 there cannot be questioned, and it is possible that true meteoric 

 fragments may have been or may yet be found in that reigon. 



Art. XIX. — History of the Changes in the Mi. Loa Craters • 

 by James D. Dana. Part I. Kilauea. Continuation of 

 the Summary and Conclusions. 



[Continued from xxxiii, 433; xxxiv, 81, 349; xxxv, 15 (Jan., 1888).] 

 II. SIZE OF THE KILAUEA CONDUIT. 



To appreciate the power at work in Kilauea and understand 

 its action we should know, if possible, the diameter of the 

 lava- conduit ; and for this we have to look to its condition 

 both in times of eruption and in periods of relative quiet. 



In view of the greatness of the discharge in 1823 — so under- 

 mining, owing to its extent, as to drop abruptly to a depth of 

 some hundreds of feet the floor of the crater, leaving only a 

 narrow shelf along the sides — we reasonably conclude that, at 

 that time, the conduit beneath was of as large area as the 

 Kilauea pit itself — or nearly seven and a half miles in circuit. 

 We may also infer that, immediately before the discharge, 

 wherever there was a lava-lake, the liquid top of the conduit 

 was up to the floor of the crater, and elsewhere not very far 

 below it. The inference is similar from the eruptions of 1832 

 and 1840. When the floor of the pit fell at the discharge in 

 1840, it was not thrown into hills and ridges, as it might have 

 been had it dropped down its 400 feet to solid rock in conse- 

 quence of a lateral discharge of the lavas beneath ; on the 



Am. Jour. Sci. — Third Series, Vol. XXXV. No. 207.— March, 1888. 

 13 



