There have been since that time numerous eruptions, which it would be tedious to mention in detail; but two of them are worthy of notice. During an eruption in February 1848, a column of vapours arose from the crater about forty feet high, presenting a variety of colours; and a short time afterwards there arose ten circles, which were black, white, and green, and which ultimately assumed the form of a cone. A similar appearance had been observed in 1820. More recently, in May 1855, a great stream of glowing lava, about two hundred feet in breadth, flowed towards a vast ravine nearly a thousand feet in depth. The first descent into this chasm is a sheer precipice, over which the lava dashed heavily, forming a magnificent cascade of liquid fire. Of the buried cities of Herculaneum and Pompeii no traces were discovered till the year 1713, when some labourers, in digging a well, came upon the remains of Herculaneum about twenty-four feet underground. Little attention, however, was paid to the discovery at that time; but in 1748 a peasant, digging in his vineyard, stumbled on some ancient works of art. On sinking a shaft at this spot to the depth of twelve feet, the remains of Pompeii were found. This discovery led to further researches, and the exact positions of the two cities were erelong ascertained. The work of disinterment has continued with little interruption from that to the present time, and many valuable specimens of ancient art have been brought to light. The greatest progress has been made at Pompeii; because the stuff, in which it was buried, is far looser than that which covers Herculaneum. In the former city, although it was anciently reckoned only a third-rate place, there have already been discovered eight temples, a forum, a basilica, two theatres, a magnificent amphitheatre, and public baths. The ramparts, composed of huge blocks of stone, have also been exposed. One of the most remarkable places is the Cemetery. It consists of a broad path covered with pavement, and bordered on either side with stately monuments, placed over the tombs of the wealthy citizens of the place, and in which whole families have been interred.