SDUFRIERE, AND ON A VISIT TO MONTAGNE PELEE, IN 1902. 
519 
of Pelee and the Soufriere. It is to Ido hoped that the investigations of the French 
Commissioners will greatly advance our knowledge in this respect, for the gases 
of the Caribbean volcanoes may be supposed to present important points of 
difference from those winch accompany less violent and more continuous activity. 
We regret that the results of our own inquiries are so purely negative in 
character, but St. Vincent does not offer tli,e conditions necessary for the 
investigation. 
The Physical Condition of the Magma .—Accounts liave already appeared of the 
composition and structure of the dust which fell on Barbados on May 7th,* and of 
the earlier falls of ashes in St. Pierre and Fort de France.! It has not yet been 
possible for us to find time to make a comparative study of all the specimens wliiclr 
we have collected during our visit to the West Indies, or have been sent us Ijy 
correspondents residing there. But there are certain general conclusions regarding 
the composition and structure of tlie materials emitted wliich we may draw from the 
facts at present l)efore us, which throw some liglit on the causes which determined 
tire magma to assume the form of a dust cloud. 
All the samples, and notably the Barbados dust, contain a very large proportion 
of crystalline fragments of volcanic minerals, often Irroken, but frequently showing- 
perfect crystalline form. Volcanic glass is present also, in fine threads and liroken 
splinters and in thin pellicles, coating the surface of the crystals. The same material 
occasionally forms little rounded pellets, in which small microliths may lie seen 
embedded in the glassy matrix. That the Barbados dust should be so largely of 
a crystalline nature bas awakened general astonishment, especially when it is 
compared with the fine air-borne dust of Krakatoa and Cotopaxi. The glassy 
fragments are of lower specific gravity than the minerals, and wliile the latter 
frerpiently are suh-cubical in form, the formei- are higlily irregular, and have a very 
large surface in comparison with their volume and weight. In consequence, the 
splinters of glass shoidd fall tlirough the air more slowly, and should lie carried Iiy 
the wind to greater distances before subsiding, than the heavier and more compact 
minerals. The ash Avliich fell on ships some 200 or 300 miles to the east of Barbados 
* JoHX S, Flett and tV. Pollard, ‘ Quarterly Journal Geological Society,’ vol. Iviii., p. 368. 
J. S. Diller, “ 5Flcanic Pocks of ^lartinirpie and St. Vincent,” ‘ National Geographic Magazine,’ 
vol. xiii., ji. 285. 5V. F. IIilderraxd, “ Chemical Discussion of Analyses of Volcanic Ejecta from 
Martinicpie and St. Vincent,” ‘National Geographic Magazine,’vol. xiii., p. 296. John D. Falconer, 
‘ Nature,’vol. Ixvi., p. 132. Professor C.irmody, Blue Book on “Volcanic Eru 2 itions in St. Vincent and 
INIartinicpie in May, 1902,” p. 83. Loxgfield SauTir, Blue Book on “Volcanic Eruptions in St. Vincent 
and Martinique in May, 1902,” p. 79. T. C. Porter, ‘Nature,’ vol. Ixvi., ji. 131. 
t Michel Levy, “Sur la Composition des Cendres Projetees, le 3 Mai, 1902, par la Montague Pelee,” 
‘ Comptes Eendus,’ 134, p. 1123. MM. A. Lacroix, Roi.let de l’Isle & Giraud, “ Sur I’Fruption de la 
Martinique,” ‘ Comptes Rendus,’ vol. cxxxv., p. 377. A. Lacroix, “ Sur les Roches rejetees par 
I’Fruption actuelle de la Montague Pelee,” ‘Comptes Rendus,’ vol. cxxxv., p. 451. T. G. Boxxey, 
‘Qitarterly Journal Geological Society,’ vol. Iviii., p. 86, 1902. 
