Intelligence and Miscellaneous Articles. 331 



tinued for weeks and months, or more, by which the mountain is 

 often ultimately eviscerated, its summit and heart beinj^ blown into 

 the air, and scattered in fragments or ashes around — not foundering 

 into the cavity and remaining there as they represent. He instances 

 the great crater of Vesuvius formed under his eyes in 1822 by explo- 

 sions lasting twenty days ; and judging from the quantity of frag- 

 mentary matter then ejected and falling around, comparing it with the 

 far greater quantities thrown up occasionally by eruptive paroxysms 

 in other quarters of the globe, he asserts his belief that in the latter 

 cases craters may be, and are, formed, of several miles in diameter, 

 nothing remaining of the whole mountain except the wreck of its 

 base, as we see in Santorini, the Cirque of Teneriife, and so many 

 other circular clifF-ranges surrounding extinct or active volcanic 

 vents. He expresses his astonishment that von Buch and Humboldt 

 should have supposed Vesuvius to have " sprung up like a bubble 

 in one day, just as we now see it," in the year 79 a.d., and not to have 

 increased since ; and shows that even within the last hundred years 

 great changes have taken place in the form of that mountain, and 

 that the relation of Pliny of the phenomena witnessed by him is in- 

 consistent with the idea of upheaval, and demonstrative of the 

 occurrence of an eruptive paroxysm by which the upper part of 

 Somma was blown by degrees into the air, and the crater of the 

 Atrio formed, in which the subsequent eruptions of eighteen cen- 

 turies have raised up the cone of Vesuvius. 



In recapitulation, the author declares that the characters of all 

 volcanic mountains and rocks are simply and naturally to be ac- 

 counted for by their eruptive origin, the lavas and fragmentary matters 

 accumulating round the vent in forms determined in great degree by 

 the more or less imperfect fluidity of the former, which, as in the 

 case of some trachytic lavas, glassy or spongy, may and do congeal 

 in domes or bulky masses immediately over, or in thick beds near 

 the vent, or, as in that of some basaltic lavas, may flow over very 

 moderate declivities, to great distances ; and consequently that the 

 upheaval- or elevation-crater-theory is a gratuitous assumption, un- 

 supported by direct observation and contrary to the evidence of facts. 

 He concludes by rejjresenting its continued acceptance to be dis- 

 creditable to science, and an impediment to the progress of sound 

 geolog}', inasmuch as false ideas of the bubble-like inflation, at one 

 stroke, of such mountains as Etna or Chimborazo must seriously 

 aflfect all our speculations on Geological Dynamics, and on the 

 nature of tlie subterranean forces by which other mountain-ranges 

 or continents are formed. 



XXXV. Intelligence and Miscellaneous Articles. 



ON THE CONSTITUTION OF TITANIFEROUS IRON ORES. 

 BY PROF. RAMMELSBERG. 



RAMMELSBERG has publislied an elaborate investigation of 

 the titaniferous iron ores, the principal results of which are as 

 follows : — 



1. The greater number of the titaniferous iron ores, among them 



