THE ANTILLEAN VOLCANOES. 277 



the futility of attempting escape) to photograph the swirling tongue 

 of flame by which the cloud was rent, and this picture must some day 

 tell whether the fire was lightning or the combustion of inflammable 

 gas. 



Other external features of the Vulcanean throes, especially in 

 Mont Pelee, were the detonations heard 200 miles away (those of 

 Xrakatoa were audible over 1,000 miles in all directions, almost 

 3,000 in one) ; the seismic tremors felt throughout most of the Lesser 

 Antilles; the magnetic shock noted by suitably equipped laboratories 

 from Paris to Honolulu, or a full third of the way about the globe; 

 and especially the solid and gaseous ejectamenta discharged skyward 

 and distributed hundreds of miles in every direction. At Fort de 

 France it was estimated that the greater discharges rose six miles from 

 the crater, seven miles above the level of the sea; by triangulation 

 Bernadou determined the height of the minor discharge of May 30 

 at 15,500 feet, or something less than three miles (the mean estimate 

 of the height of the Krakatoan discharge in 1883 was 17 miles). The 

 cloud of steam and other gases, with their burden of rock-powder, 

 spread in typical mushroom shape with such rapidity that neighboring 

 islands up to a hundred miles away were darkened, and the dust-rain 

 began to fall within three hours; on Barbados, 100 miles from La 

 Souffriere and 125 from Mont Pelee, the dust-rain reached a depth 

 of a quarter of an inch, and brought down sulphurous gases. The early 

 analyses indicate that the greater part of this material is a crystalline 

 hypersthene-andesite, i. e., the heavier portion of a rather acidic lava 

 of which the more glassy portions are thought by Teall Ho have been 

 vanned away and deposited elsewhere' {Nature, Vol. 66, p. 130) ; while 

 according to Diller and Steiger some of the grains collected 275 miles 

 southeast of St. Vincent have the astonishingly high specific gravity 

 of 3.3, and the insoluble dust contained .11 per cent, of sulphur, while 

 the dust collected on Barbados was notable for the abundance of mag- 

 netite (Science, Vol. XV., pp. 947-950). Nearer the crater of Mont 

 Pelee, the dust — 'ashes' of the press reports, 'lapilli' of the books — 

 lies like snow in drifts and sheets sometimes several feet in depth, and 

 is mingled with fragments of pumice or bombs of denser rock, perhaps 

 torn from the throat of the crater. Naturally the rock-rain was cool 

 at Barbados and other remote stations; on St. Vincent, after the out- 

 break of La Souffriere, and on Martinique under each eruption of 

 Mont Pelee, the falling rock was warm, even hot; an officer of one of 

 the vessels wrecked in the roadstead of St. Pierre escaped the first 

 shock only to be smitten down by a falling mass of half-molten rock; 

 Russell found indications that some of the falling dust was hot enough 

 to scorch the skin of victims but not to fire cotton garments; and a 

 correspondent of Nature reiterates the incredible report that the sand 



