KILAUEA, HAWATL 199 
The scoria is mostly glassy in texture, a kind of ferruginous 
basaltic obsidian ; and as shown by Sir James Hall, this glassy con- 
dition of a rock will fuse at less than half the temperature required to 
fuse the same material in its stone-like character.* It is the result, as 
has been often stated, of rapid cooling. 
The capillary glass of Kilauea, called Pele’s hair, is made from the 
scoria here described, or rather from lava that would have constituted 
scoria had it cooled upon a flowing stream. 
The following are the results of analyses by Prof. B. Silliman, Jr. 
of Pele’s hairt and lava from the crater. The last two are from the 
same specimen, the vitreous forming a compact exterior to the stony 
lava.t 
* Sir James Hall states that a stone, fusible at 38 degrees of Wedgewood, yields a 
glass which softened at 14° ; and if again unvitrified, fused at 35°. The general results 
are correct, although we cannot place confidence in the Wedgewood scale. The facts 
show that the material is dimorphous, or assumes a difference of texture according to the 
rate of cooling. The same variation has been detected in more recent experiments. 
t+ According to an analysis by Mr. J. Peabody, in the laboratory of Dr, C. T. Jackson, 
Pele’s hair has the following constitution : 
Silica, - E : 2 
= - 50:00 
Protoxyd of iron, - " ; c - 93:72 
Lime, - - - & = = 7:40 
Alumina, - . z : : : 6°16 
Potash, - - - ° « a 6:00 
Soda, - * r - ~ . ~ 2-00 
Capillary volcanic glass is not mentioned as occurring at any other volcano except on 
the Isle of Bourbon, where it was found by Bory de St. Vincent.—Voyage aux Iles 
@ Afrique, iii. 50. 
t The soluble portions of the minerals were first exhausted by digestion in repeated 
portions of hydrochloric acid; the insoluble residues were ignited, weighed, and the silica 
removed from them by the action of hydrofluoric acid, except No. 3, the insoluble portion 
of which was fused with carbonate of soda. The loss on this analysis may arise from the 
fact that a portion of soda was not extracted by the acid digestion. This was the case 
in Nos. 1 and 4. In the former eight per cent. and in the latter nearly two per cent. of 
soda were found in the part unattacked by the acid. 
The solution in nitric acid, after being nearly neutralized, indicated the presence of 
chlorine to a small amount in all, more abundantly in Nos. 1, 2 and 3, and less so in 
Nos. 4 and 5. 
The alkaline residue, when dissolved in water, treated with a solution of bichlorid of 
platinum, and evaporated to dryness, was entirely redissolved in alcohol, proving conclu- 
sively the absence of potassa,. 
Traces of peroxyd of iron were discovered in all the specimens, excepting the light- 
coloured specimen of Pele’s hair. 
