SOUFPJEEE, AND ON A VISIT TO VONTAGNE PELEE, IN 1902. 
521 
project showers of hot bombs and dust into the airr The later stages of the 
Pelean eruj)tions do not essentially differ from those of the eruptions of other 
volcanoes. 
There is, in fact, a considerable amount of evidence to show that that part of the 
magma which gave rise to the great black cloud was not in a state of complete fusion, 
but that even the matrix separating the individual crystals was semi-solid and 
partially crystallized.''" The glassy fragments in the dust of Pelee contain many 
microliths. According to the descriptions of Mr. J. S. DiLLER,t “at least half the 
mass (of the dust which fell on the ‘ Roddam,’ in St. Pierre on May 8th) is dark 
microlithic, more or less felty, but not vesicular ground-mass, often enclosing or 
clinging to crystals, and appears identical with the gronnd-mass of the lavas of 
Mount Pelee antedating the last eruption.” 
Professor Lacroix,"^ describing the ashes which fell in St. Pierre on May 2nd and 
3rd, 1902, says;—“The examination of the glassy matter wliich plays an important 
part in these ashes is not wnthout interest ; it is compact, with few cavities, or at 
most enclosing a few minute vesicles ; it contains very few microliths of felsi^ar, bnt 
a pretty large nnmber of opaque globulites, and occasionally some crystallites of 
hypersthene. It is not in I’eality a pumice composed of vesicular, filamentous glass, 
like that which characterised the great explosion of Krakatoa, and that which in 
pre-historic time blew out the bay of Santorin.” 
From these descriptions it is clear that a second generation of crystals had begun 
to form in the magma within the mountain, or at least in the upper part of it before 
it was forced to the surface and blown into dust by the expansion of the gases it 
contained. Mr. Diller, indeed, advances the view that these glassy fragments 
belong to the older rocks of the monntain :—“ It appears certain that the greater 
portion of the material which fell on the deck of the ‘ Roddam ’ was derived from 
the pulverisation of solid rock about the volcanic vent of Mont Pelee, and only 
a small portion from the molten magma which was the seat of the eruption.” He 
arrives at the same conclusion as a result of his examination of the dnst which fell in 
Kingstown, St. Vhncent, on May 7th, 1902:—“The larger particles are of dusty 
glass, rarely clear, and colonriess, and full of bubbles. Others contained a multitude 
of minute crystals. Those filled with these microlites are of pulverised older rock, 
while the dirty vesicular glass ones, like the ground-mass of the pumice, represent the 
molten magma of the eruption.” j; 
This theory, that much of the dust was due to the comminution of the older rocks 
of the hill, was suggested to us by Professor Jaggar, whom we met in Barbados 
* Professor Israel C. Pusseia also is of ojRiiion that the magma had partly consolidated. 
Century Magazine,’ vol. Ixiv., p. 795, September, 1902. 
t “ Volcanic Pocks of Martinique and St. Vincent,” ‘National Geographic Magazine,’ vol. xiii., p. 290. 
t ‘ National Geographic Magazine,’ vol. xiii., p. 290. 
VOL. CC.-A. 3 X 
