166 



2. What space of time would be required to heat or cool such 

 enormous masses of substances, which are very imperfect conductors 

 of caloric, to the required temperatures*? 



3. How far the explanation given of the phaenomena of the Sera- 

 peum is applicable to others in its vicinity? The admitted fact that 

 certain buildings which have also subsided still remain below the 

 level of the sea, while others have been raised to unequal heights 

 above it, makes it unlikely that any uniform cause, while it produced 

 upon them such various effects, should yet have stationed the pave- 

 ment of this temple in the self-same spot which it occupied at the 

 time of its original construction. 



The Letter from Capt. Basil Hall contains remarks on the position 

 of the three columns of the temple which are still standing; they 

 appear from his observations not to be exactly upright, but to bulge 

 over a little, all in one direction, but not to the same degree. The 

 outermost, in consequence of the tilt, has been brought into such a 

 position that the top of the column is in a line with its base, an ex- 

 traordinary accident. These remarks do not diminish our difficulties. 

 The tilting may have been occasioned by such subsidences as all 

 buildings are liable to, which are not founded upon solid rock, or it 

 may be referred to earthquakes or original carelessness, or to the 

 skill of the architect, who, by giving a deviation from the plummet 

 line to the axis of the columns (so slight indeed as not to catch the 

 eye,) strengthened his edifice against some lateral thrust, a practice 

 known to have been employed at Athens, and referred to in the let- 

 ter. Captain Hall has indeed put his veto on this last hypothesis, 

 by saying that the inclination of the columns takes the opposite di- 

 rection to that which would be required for the supposed purpose ; 

 but this cannot be known, I imagine, unless we know also the de- 

 tails of the original structure, and especially the position and con- 

 struction of the roofs. 



Shortly after this temple had been examined by Mr. Babbage, an 

 attempt to drain it effectually was made by the Neapolitan Govern- 

 ment : the stagnant water which infected the air of the neighbour- 

 hood was partly supplied from the mineral spring, partly from rain, 

 partly from the sea: the experiment failed for reasons which it is 

 not necessary to mention, Signor Nicolini, President of the Royal 

 Academy of Naples, who was entrusted with the conduct of the 

 work, and has published an account of it, discovered a rich mosaic 

 pavement a hundred palms in length at the depth of sixteen palms 

 below the level of the stagnant water, whence it appears that the 



* On a statement of Mr. Scrope's, that a current of lava after it had been 

 ejected nine months, was still flowing on the flanks of Etna at the rate of a 

 yard per day, Mr. de la Beche observes, " If lava can retain its elevated 

 " temperature when thus exposed, what length of time may we not allow for 

 " its doing so within the pipe of the volcano itself, surronnded on all sides by 

 " matter greatly heated, and like itself an exceedingly bad conductor of heat? 

 " Even in those cases where centuries elapse between the great eruptions 

 " of any given volcano, the lava is probably liquid beneath at no very con- 

 " siderable depth." 



