VOLCANO OF JOKULLO. 



29th of September, 1759. The circumstances attending the 

 production of this volcano are so remarkable, that we shall here 

 notice them in some detail.* 



An extensive plain, called the Malpays, was covered by rich 

 fields of cotton, sugar-cane, and indigo, irrigated by streams, and 

 bounded by basaltic mountains, the nearest active volcano being 

 at the distance of eighty miles. This district, situated at an 

 elevation of about 2600 feet above the level of the sea, was 

 celebrated for its beauty and extreme fertility. In June, 1759, 

 alarming subterranean sounds were heard, and these were accom- 

 panied by frequent earthquakes, which were succeeded by others 

 for several weeks, to the great consternation of the neighbouring 

 inhabitants. In September tranquillity appeared to be re- 

 established, when, in the night of the 28th, the subterranean 

 noise was again heard, and part of the plain of Malpays, from 

 three to four miles in diameter, rose up like a mass of viscid fluid, 

 in the shape of a bladder or dome, to a height of nearly 1700 feet ; 

 flames issued forth, fragments of red-hot stones were thrown to 

 prodigious heights, and, through a thick cloud of ashes, illumined 

 by volcanic fire, the softened surface of the earth was seen to 

 swell up like an agitated sea. A huge cone, above 500 feet high, 

 with five smaller conical mounds, suddenly appeared, and thousands 

 of lesser cones (called by the natives hornitos, or ovens,) issued 

 forth from the upraised plain. These consisted of clay inter- 

 mingled with decomposed basalt, each cone being a fumarolle, or 

 gaseous vent, from which issued thick vapour. The central cone 

 of Jorullo is still burning, and on one side has thrown up an 

 immense quantity of scoriaceous and basaltic lavas, containing 

 fragments of primitive rocks. Two streams, of the temperature of 

 186 of Fahrenheit, have since burst through the argillaceous vault 

 of the hornitos, and now flow into the neighbouring plains. For 

 many years after the first eruption, the plains of Jorullo were 

 uninhabitable from the intense heat that prevailed.! 



132. It appears that the cone from which Vesuvius takes its 

 present character has been the result of similar effects. 



In the description of the mountain given by Strabo, no mention 

 whatever is made of the cone which now forms its most remark- 

 able feature. The slopes of the mountain, says Strabo, were 

 regions of the greatest fertility; its summit was truncated, 

 entirely sterile, and had a burnt aspect, displaying cavities full 

 of crevices and calcined stones, from which it must be conjectured 

 that they had been formerly volcanic craters. It seems, there- 

 fore, that the cone to which the name of Vesuvius now more 



* Cosmos, vol. i. p. 229. Trans, 

 t Mantell, p. 837. 



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