J. D. Dana — History of t'he Changes in Kilauea. 221 



shaped bullets and granules around the vent ; and this is the 

 nearest the crater at present comes toward producing cinder- 

 cones. 



Besides making driblet-cones, the projectile work raises 

 somewhat the borders of the lakes. Further, the small over- 

 flows, lapping in succession over the borders, often make them 

 steep, and keep increasing their height until a heavier out-flow 

 sweeps one side or another away. 



A third incidental result of the projectile action is the mak- 

 ing of ca/pillary glass, or Pele's hair, from the glassy part of 

 the lavas. In the jetting and splashing of the lavas, the flying 

 clots and drops pull out the glass into hairs, just as takes place 

 in the drawing apart of a glass rod when it is melted at middle. 

 This is the explanation of Mr. Coan and others who have ob- 

 served the action. Mr. Brigham says that " the drops of lava, 

 thrown up, draw after them the glass thread, or sometimes two 

 drops spin out a thread a yard long between, them." His new 

 observations of 1880 (xxxiv, 22) accord with this explanation 

 but are remarkable for the length and size of Pele's tresses that 

 he reports as hanging from the roofs of the fiery recesses. In 

 my visit in 1840 to one of the smaller boiling lakes, I saw the 

 rising and falling jets, and the work of the winds in drifting 

 the spun glass ; but my conclusion erred in attributing the 

 spinning also to the winds. 



Captain Dutton's observations led him to another explana- 

 tion, as follows:* " The phenomenon of Pele's hair has gener- 

 ally been explained as the result of the action of the wind 

 upon minute threads of lava drawn out by the spurting up 

 of boiling lava. Nothing of the sort was seen here, and yet 

 Pele's hair was seen forming in great abundance.. Whenever 

 the surface of the liquid lava was exposed during the break up 

 the air above the lake was filled with these cobwebs, but there 

 was no spurting or apparent boiling on the exposed surface." 

 He then speaks of the vesicles made by the energetic escape of 

 water-vapors, as solidification at the surface commences, and of 

 their " walls as capable of being drawn out into threads as in the 

 case of glass." The descending of the pieces of cooled crust 

 " produces eddies and numberless currents in the surface of the 

 lava;" and as'a consequence "the vesicles are drawn out on the 

 surface of the current with exceeding tenuity, producing 

 myriads of minute filaments " and the air agitated by the heat 

 "lifts and wafts them away." "It forms almost wholly at the 

 time of a break-up ; the air is then full of it." 



The microscopic structure of the capillary glass has been 

 studied with care by C. Fr. W. Krukenberg.f" In his fifty 



* Report, p. 108. 



f Micrographie der Glasbasalte vom Hawaii ; petrographische Untersuchung, 

 38 pp. 8vo, with 4 plates; Tubingen, 1811. 



