Arago and others maintained that the surface on which the temple stands has been depressed, has _remained under the sea, and has again been elevated_. Russager, however, contends that there is nothing in the vicinity of the temple, or in the temple itself, to justify this bold hypothesis. Every thing leads to the belief that the temple has remained unchanged in the position in which it was originally built; but that the sea rose, surrounded it to a height of at least twelve feet, and again retired; but the elevated position of the sea continued sufficiently long to admit of the animals boring the pillars. This view can even be proved historically; for Niccolini, in a memoir published in 1840, gives the heights of the level of the sea in the Bay of Naples for a period of 1900 years, and has with much acuteness proved his assertions historically. The correctness of Russager’s opinion, he states, can be demonstrated and reduced to figures by means of the dates collected by Niccolini.--See _Jameson’s Journal_, No. 58.
At the present time the floor is always covered with sea-water. On the whole, there is little doubt that the ground has sunk upwards of two feet during the last half-century. This gradual subsidence confirms in a remarkable manner Mr. Babbage’s conclusions--drawn from the calcareous incrustations formed by the hot springs on the walls of the building and from the ancient lines of the water-level at the base of the three columns--that the original subsidence was not sudden, but slow and by successive movements.
Sir Charles Lyell (who, in his _Principles of Geology_, has given a detailed account of the several upfillings of the temple) considers that when the mosaic pavement was re-constructed, the floor of the building must have stood about twelve feet above the level of 1838 (or about 11½ feet above the level of the sea), and that it had sunk about nineteen feet below that level before it was elevated by the eruption of Monte Nuovo.
We regret to add, that the columns of the temple are no longer in the position in which they served so many years as a species of self-registering hydrometer: the materials have been newly arranged, and thus has been torn as it were from history a page which can never be replaced.