INTERIOR LAND CHANGES. 423 



Bokhara and the Oxus, utterly destitute of vegetation, which have a remarkably uniform 

 aspect. The whole of them had the shape of a horse-shoe, the outer rim presenting itself 

 to the north, the direction of the prevalent winds of the country. Towards this direction, 

 the mounds sloped, but were invariably precipitous on the interior side, showing plainly 

 the influence of the winds in heaping them up, and arranging their contour. While 

 a high wind was blowing, the particles at the surface passed from one mound to another, 

 ' and wheeled in the interior of the semicircle. The great river of this district, the Oxus, is 

 supposed to have been compelled to alter its course, or at least to have lost one of its 

 branches, by the advance of the desert. According to Strabo, goods from India were 

 brought along this river into the Caspian, and from thence were transferred into Europe ; 

 a fact, which Varro informs us was ascertained by Pompey in the Mithridatic war. The 

 Oxus now enters the sea of Aral, but dry river-beds between Astrabad and Khiva are 

 thought to be the memorials of the channel from which the encroachment of the sand has 

 expelled its waters. 



In active volcanic districts, we have an instrument of change occasionally at work, of 

 irresistible energy, sublime in the manifestations of its power, but happily having a more 

 confined field of operation than any of the causes which have been noticed as modifying 

 the aspect of the globe. It is near the centres of volcanic action that alterations are 

 effected by the play of the subterranean furnaces, and these occur here upon a vast scale, 

 a permanent rise being frequently given to the surface of the adjacent country by the 

 discharge upon it of enormous volumes of lava, stones, and ashes. The complete burial 

 of the ancient cities of Pompeii and Herculaneum illustrates the immense amount of 

 matter then ejected from Vesuvius, the first recorded instance of its eruption, in the 

 month of August, A. D. 79. We are told by Diodorus Siculus that the mountain had 

 " many signs of having been burning in ancient times," and Strabo infers its igneous 

 origin from the nature of its rocks ; but at the time in question, its slopes were richly 

 cultivated and proverbially fertile, and just before, its top, a slightly concave plain, 

 according to Virgil's description, had been the camp where the Romans- besieged the 

 brave Spartacus and his revolted slaves. Martial's epigram testifies to the harmlessness 

 of Vesuvius anterior to the disturbance to which we refer, a character which had certainly 

 belonged to it for several ages. 



" Here verdant vines o'erspread Vesuvius' side ; 

 The generous grape here pour'd her purple tide, 

 This Bacchus lov'd beyond his native scene ; 

 Here dancing satyrs joy'd to trip the green, 

 Far more than Sparta this in Venus' grace ; 

 And great Alcides once renowned the place* 

 Now flaming embers spread dire waste around, 

 And gods regret that gods can thus confound." 



It was during the first movement of Vesuvius after ages of inaction, and perhaps the most 

 formidable of its eruptions in modern times, that the elder Pliny lost his life, of which we 

 have a description by his nephew in two letters to Tacitus. " He was at that time," 

 remarks the narrator^ " with the fleet under his command at Misenum," the Portsmouth 

 of the Roman navy, as it has been styled. " On the 24th of August, about one in the 

 afternoon, my mother desired him to observe a cloud which appeared of a very unusual 

 size and shape he immediately arose, and went out upon an eminence, from whence he 

 might niore distinctly view this very uncommon appearance. It was not at that distance 

 discernible from what mountain this cloud issued, but it was found afterwards to ascend 

 from Mount Vesuvius. I cannot give you a more exact description of its figure, than by 

 resembling it to that of a pine-tree, for it shot up to a great height in the form of a 



