1871.] 127 [Shaler. 



Carguairazo, one of the Andes. Some of these lakes con- 

 tain beds of diatoms twelve feet in thickness. He also made 

 a brief reference to the multitude of extinct volcanoes in 

 the vicinity of Ceborujo. 



Dr. Charles Pickering, referring to an observation made by 

 Dr. Jackson at the preceding meeting, to the effect that the 

 central heat held water on the surface of the globe, said he 

 had seen this exemplified on a small scale at Hawaii. All 

 the water there is distilled by the heat below, condensed by 

 the vegetation and collected in pools, from which the supplies 

 were taken. Immediately after an eruption, when he visited 

 the volcano, the crater was empty. He could detect no 

 steam or vapor in the fields of lava. There rises from the 

 lava a kind of smoke, which is very conspicuous. He could 

 not say what it was, but thought it was not vapor. The 

 winds there always blowing in one direction, he had visited 

 the regions to leeward of the volcano and found quantities 

 of "Pele's hair" in rolls. The eruption of Kilauea, he said, 

 differs in some respects from that of . Mauna Loa. In the 

 latter, the lava breaking out eight or ten miles from the sum- 

 mit, flows eighty or ninety miles to the sea. The ascent of 

 Kilauea is so gradual that it is difficult for one ascending to 

 its summit to appreciate its altitude. The great crater does 

 not overflow, but when .full splits the island, opening a way 

 for the lava thirty miles to the sea. 



Mr. Brigham, referring to the opinion that water was neces- 

 sary to an eruption, said, that with the ocean all around it, 

 the vapor from this volcano is always dry. It is blown down 

 toward the sea and its moisture, if it contained any, would be 

 deposited, but the region over which it passes is dry and bar- 

 ren. He found it necessary to wear a wet cloth over his face 

 to protect respiration while passing through it, and it was 

 quickly dried. It is mixed with sulphur, but what gives its 

 occasional black appearance ; he could not say. The rocks 



