SOUFKIEKE, AND ON A VISIT TO MONTAONE PELEE, IN 1902. 52:3 
We have seen that the magma of these Antillean volcanoes, or at least the 
uppermost part of it which gave rise to the great black cloud, was to a large extent 
crystallized, contained comparatively little fluid matter, and that it was accordingly 
near the temjjerature of consolidation, or may even in part have solidified already. 
These may all ha.ve been powerful factors in determining it to assume the form of 
a dust cloud as soon as the retaining pressures were relieved, and the vast quantities 
of steam and other gases it contained were free to expand. 
But the chemical aspects of the problem must not he neglected; they may be of 
even greater importance than the physical. Both magmas are andesitic, but the 
analyses and microscopic investigations which have already been published make it 
certain that they are not exactly the same, so that it does not appear likely that the 
dust-avalanche type of eruption is a consequence merely of the presence of a magma 
with a certain narrowly-restricted chemical composition. 
On the otlrer hand, it is a significant fact that many of the most terrible instances 
of disastrous and sudden volcanic e.xplosions have been furnished by volcanoes 
emitting hypersthene andesite. Krakatoa and Bandaisan are two examples of quite 
recent date. This group of rocks is, of course, a very diverse one, and includes many 
important variations ; but as contrasted with the basalts, which in so many cases give 
rise to floods of liquid lava quietly welling out of craters or fissures, they seem 
predisposed to violent and disruptive activity. The rarity of dykes in St. Vincent, 
and the al)undance and thickness of the sheets of coarse agglomerate, point to the 
same conclusion. 
What influeiice the nature of the gases present in such quantities may exert is a 
problem equally interesting and obscure. Till we know more of what these gases are, 
and in what jjroportions they exist in the- magma, it is premature to enter into a 
discussion of the jjart they play in the origination of the great black cloud. Any 
conditions whatever, whether chemical or otherwise, which diminisii the cohesion of 
the magma in which the gases were absorbed will, prima facie, facilitate the 
conversion of the mass from a spongy frotli into a cloud of liquid droplets. 
The Cause of the Deaths. 
Owing to the exigencies of the case, it was impossible to ])erform autopsies on the 
bodies of the dead in St. Vincent, and however much we may regret this from a 
scientific point of view, we must recognise that the first call on the energies of the 
medical men was to attend to the wounded, and give them what assistance they 
could. At first the number of doctors in the island was too small to enable them to 
cope with the sudden emergency, but help was rapidly provided from the adjacent 
British islands, and the final I'esults were brilliant. It was several days before the 
state of the volcano warranted the exploration of the devastated country on an 
extensive scale, and when the bodies were finally all discovered and interred, they 
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