40 
Volcano of Kirauca. 
height of twenty feet, against the walls of the reservoirs, 
the current of air, filled with foam by the fury of their 
agitation, carries away the spray which they scatter, 
spins it out in threads, makes it float like snow or 
cobwebs, and deposits it at a distance over the rugged 
surface of the congealed masses in delicate threads of 
woven glass. # 
So, in the midst of the very torrents of fused minerals 
cast up from the bowels of the earth, and seeming to 
threaten a portion of its surface, we see on the one hand 
muriate of ammonia tranquilly forming in elegant pyra¬ 
mids of an elongated and hexahedral shape, and even in 
the unusual form of cubical crystals; on the other hand 
the petro-alumines of Tolfa and sulphate of alumine with 
its acicular crystals, securely constructing its appointed 
forms. 
On the S.E. of the crater the contrast seems still 
more wonderful. Here the vast walls of its basin, six 
hundred feet high, bear evident marks of torrents of lava 
which have spouted from the sides of the clifls in gushes, 
depositing mounds^f sulphur at the base more extensive 
than those of Solfaterra, and everywhere sparkling with 
the rarest crystals, sometimes pure and clear, sometimes 
studded with sulphuret of arsenic, or mixed with it. I 
observed and collected more than ten secondary forms of 
the primitive octahedron, and at least seven modifi- 
cations under which the substances are found:—1. Simple 
octahedrons, with all modifications produced by trunca¬ 
tions of the summit, edges or angles of the primitive form. 
2. Amorphous masses. 3. Dentiform and mammillary. 
4. Stalactitic. 5. Granulated and compact. 6. Glo¬ 
bular. 7. Acicular. 
No volcanic theory applies better to these remarkable 
facts displayed by Kirauea than that of Sir Humphrey 
* Called “Pole’s hair” by the natives. — Voyage of the Blonde. 
