30
THE
ERUPTION
OF
PELÉE
destruction of K r a k a t a o in 1883, is known to have produced any magnetic disturbance other t h a n of a local character. B. The production of electric or pyro-electric illuminations in the volcanic cloud seemingly far surpassing those t h a t had ever before been noted, and presenting features t h a t had not hitherto been recorded. C. The propagation of sound-waves to distances of 800 (and probably 1000 or more) miles, the explosion of May 8 having been heard with terrific intensity at Maracaibo, the sound, as likewise t h a t accompanying the eruption of August 30, seeming to come from above. D. The transmission of a shock-wave, or earth tremor, as would appear from the single observation made at Zi-ka-Wei, in China, passing completely through the earth,—a condition t h a t had only once before been noted (in con nection with the K r a k a t a o eruption). E. The formation of a remarkable series of "after-glows," or brilliant red skies, which doubtless made the passage over the entire earth, and were ob served off the Venezuelan coast, at Los Angeles (California), Honolulu, Bom bay, Funchal (Madeira), in most parts of Europe, from Italy to England, and along nearly the entire Atlantic border and over the central portion of the United States. These skies, with the a t t e n d a n t Bishop's ring, were less brilliant t h a n those which followed the K r a k a t a o eruption, occupied a position much nearer to the earth's surface, and travelled with somewhat less than half the velocity. F. The emission of prodigious quantities of steam and ash, the steamcolumn passing at times vertically through the zones of both the trade and anti-trade winds and to heights above the summit of the volcano estimated to be from four to six miles. The furthest distance at which the falling ash was noted on the surface of the sea appears to have been about 700 (900?) miles. G. The bursting forth of an explosive tornadic blast, of a nature perhaps not yet entirely understood, whose death-dealing and destroying effects have had no parallel in the earth's history. The event of August 30 was a repeti tion of t h a t of May 8. H. The extrusion from the crater-summit of the volcano of a giant core of solid lava, a veritable tower or obelisk, which at its most lofty period ( J u n e July, 1903) rose to about 1020 feet, with a thickness at the base of 350-500 feet (shortest and longest diameter). I. The eruptions of Pelée took place in times of atmospheric stability, were unaccompanied by earthquake movements, and had no relation to dis tinctive phases either of the moon or of the sun. The ejected products, exclusive of the tower and its immediate base, were of a fragmental,* aqueous, and gaseous nature, there having been no true lava-flows (at least, not beyond the crater-limits). * T h e fragmental p r o d u c t s of t h e Pelée e r u p t i o n s are essentially a highly acidic h y p e r sthene-andesite, whose general composition, as d e t e r m i n e d b y t h e analyses of H i l d e b r a n d , Mirville, Pollard, a n d others, m a y be s t a t e d t o be SiO , 53-62 per cent.; A1 O (and Fe O ), 2
2
2
2
3