VOLCANO VOLNEY. 



843 



violent shock was then felt, and a stream broke out 

 from the side of the cone, at no great distance from 

 it* apex. Shortly after, other streams, to the num- 

 ber of six, broke out in succession, still lower down 

 the mountain, but all in the same straight line. In 

 1819, three large mouths opened very near those 

 which were formed in the eruptions of 1811, from 

 which flames, red-hot cinders and sand were thrown 

 up, with loud explosions. A few minutes after- 

 wards, another mouth opened below, from which 

 flames and smoke issued ; and finally, a fifth, lower 

 still, whence a torrent of lava flowed, which spread 

 itself with great velocity over the valley Del Bove. 

 This stream flowed two miles in the first twenty- 

 four hours, and nearly as far in the succeeding day 

 and night. 



As the last example of modern volcanic erup- 

 tions, we shall mention that of Jorullo, in Mexico, 

 in 1759. The plain, which was the site of the 

 eruption, is thirty-six leagues from the sea, and, at 

 the time of the eruption, was occupied by fertile 

 fields of sugar-cane and indigo. In the month of 

 June, hollow sounds, of an alarming nature, were 

 heard, and earthquakes succeeded each other for 

 two months, until, in September, flames issued from 

 the ground, and fragments of burning rocks were 

 thrown to prodigious heights. Six volcanic cones, 

 composed of scoriae and fragmentary lava were 

 formed on the line of a chasm which ran in the di- 

 rection from north-north-east to south-south-west. 

 The least of these cones was 300 feet in height ; 

 and Jorullo, the central one, was elevated 1600 feet 

 above the level of the sea. A subsequent eruption 

 of Jorullo happened in 1819, accompanied by an 

 earthquake. The city of Guanaxuato, distant about 

 140 miles from Jorullo, was covered with ashes, to 

 the depth of six inches, from this eruption. 



During the last century, about fifty eruptions are 

 recorded of the five European volcanoes, Vesuvius, 

 .ZEtna, Volcano, Santorin, and Iceland ; but many 

 beneath the sea, in the Grecian Archipelago, and 

 near Iceland, may, doubtless, have passed unnoticed. 

 If some of them produced no lava, others on the 

 contrary, like that of Skoptar Jokul, in 1783, poured 

 out melted matter for five or six years consecu- 

 tively. Now, if we consider the active volcanoes 

 of Europe to constitute about a fortieth part of 

 those already known on the globe, and calculate 

 that, one with another, they are about equal in ac- 

 tivity to the burning mountains in other districts, 

 we may then compute that there happen on the 

 earth about 2000 eruptions in the course of a cen- 

 tury, or about twenty every year, or one in eighteen 

 days. However inconsiderable, therefore, may be 

 the superficial rocks, which the operations of fire 

 produce on the surface, we must suppose the sub- 

 terranean changes now constantly in progress to be 

 on the grandest scale. The loftiest volcanic cone? 

 must be insignificant when contrasted with the pro- 

 ducts of fire in the nether regiona. 



One of the earliest hypotheses to account for 

 volcanic eruptions is that which attributes them 

 to the eructations of a perpetual central fire, to 

 which, however, the nature of the lava, the method 

 of its projection, and, above all, the known laws of 

 the communication of heat, are insurmountably op- 

 posed. The sudden evolution of steam has also fre- 

 quently been resorted to. They have also been 

 referred to the ignition of beds of coal ; and Wer- 

 ner supposes that the fire thus produced fused the 

 circumjacent rocks, and formed lava. Others have 

 called sulphur, pyrites, petroleum, and bitumen to 



their aid, but have sought in vain for the necessary 

 supply of oxygen, without which thpse combustibles 

 could not perform their required part ; and, indeed, 

 if we grant an unlimited supply of that element, the 

 projectile force the vapour still remains to be 

 accounted for. Others have imagined a great depot 

 of electric matter pent up in certain submarine and 

 subterranean caverns, and occasionally sallying forth 

 to fuse iind blow up the surrounding materials. 

 The most plausible theory of volcanoes is that 

 suggested by Sir H. Davy, soon after he had disco- 

 vered the nature of the earthy and alkaline bodies. 

 Indeed, it enables us, in most cases, upon just prin- 

 ciples of sound analogy, to explain their origin ; for 

 lava consists of earthy and alkaline bodies, ejected 

 in intense ignition ; and it is associated with va- 

 pour, with explosions of hydrogen gas, with the pro- 

 duction of nitrogen ; and, in short, there is every 

 concomitant circumstance to lead to the conclusion 

 that there exist in the bowels of the earth, masses 

 of those highly inflammable metallic bodies, consti- 

 tuting the bases of the earths and alkalies ; and 

 these and water are essential requisites for the 

 production of the phenomena that precede, accom- 

 pany, and follow the eruption of volcanoes ; they 

 may be referred to, as accounting for the earth- 

 quakes, the explosions and the gaseous products ; 

 and they are the only agents, with which we are 

 acquainted, capable of fulfilling all the requisites. 

 How or where these bodies exist, at what depths, 

 in what quantity, and how accessible to water, are 

 questions that we cannot solve ; but it is a curious 

 fact, that water is always found connected with vol. 

 canoes. Vesuvius, ^Etna, and Hecla are upon the 

 verge of the sea ; and in the vicinity of the burning 

 mountains of the Cordilleras there are lakes ; and 

 it has been observed, that springs and lakes sud- 

 denly dry up previous to the active eruption of a 

 volcano. 



VOLGA. See Wolga. 



VOLHYNIA ; a government of the Russian em- 

 pire, between the governments of Grodno and Po- 

 dolia ; square miles, 29,300 ; population, about 

 1,000,500. While Poland was independent, Vol- 

 hynia formed a province of that kingdom, which 

 bordered with the Ukraine on the south-east. The 

 soil is fertile, producing wheat and rye, and its 

 pasture lands are extensive ; but a great part of the 

 surface is forest. From its frontier situation, it has 

 often been exposed to the evils of invasion. Since 

 1793, it has been in the possession of Russia. VoL 

 hynia was in insurrection in 1831, but shared the 

 fate of Poland, when that unfortunate country was 

 again trampled under foot by the victorious barba- 

 rians. See Poland, and Russia. 



VOLITION. See Will. 



VOLNEY, CONSTANTINE FRANCIS CHASSEBCEUF, 



count de, peer of France, a celebrated French 

 writer, was born at Craon, in Brittany, in 1767. 

 Inspired, at an early age, with a desire to visit 

 foreign countries in search of knowledge, he no 

 sooner became master of a small patrimonial estate, 

 than he converted it into money, and embarked for 

 the Levant, travelled through several parts of 

 Egypt and Syria, and, after a residence for some 

 time in a Maronite convent on mount Libanus, for 

 the purpose of studying the Oriental languages, re. 

 turned to France, whence he had been absent more 

 than two years. The fruits of his inquiries ap- 

 peared in his Voyage en Syrie et en Egypte (2 vols., 

 Svo.), which was translated into English, Dutch 

 and German. This work procured him much re- 



