106 THE WONDERS OF GEOLOGY. Ljsct. I. 



which are constantly in action in the interior of the globe. 

 We shall hereafter have occasion to demonstrate that dislo- 

 cations of the strata, and elevations of the bottom of the 

 ocean, and subsidences of the land, and eruptions of melted 

 mineral matter, have taken place from the earliest periods 

 within the scope of geological inquiries. ] 



The expansive power of caloric, even in ordinary circum- 

 stances, is very considerable, as is shown by the instrument 

 called a pyrometer, which illustrates a fact continually 

 presented to our notice, namely, the expansion of a bar of 

 metal by heat, and its contraction, by cooling, into its 

 original dimensions. The expansion of solid bodies by 

 heat, when effected on a large scale, gives rise to many 

 interesting phenomena. The careful experiments made by 

 Colonel Totten, on the expansion of granite, marble, and 

 other rocks, by variations of temperature, have shown that 

 the mere expansion, or contraction, of extensive beds of 

 these materials, will account for the elevation and subsidence 

 of considerable tracts of country, and explain many analo- 

 gous phenomena.* 



54. Subsidence and elevation of the temple of 

 Jupiter at Puzzuoll — One of the most interesting 

 examples of local elevation and subsidence, apparently 

 resulting from this cause, is that afforded by the remains of 

 the celebrated temple of Jupiter Serapis, at Puzzuoli. 



These ruins are situated on the northern shore of the 

 Bay of Baiae, at no great distance from the Solfatara, 

 and consist of the remains of a large building of a quadran- 

 gular form, seventy feet in diameter ; the roof of which 

 was supported by twenty-four granite columns, and twenty- 

 two of marble, each formed of a single stone. Many of the 

 pillars are broken and their fragments strewed about the 

 pavement, but three remain standing, and on them are 



* American Journal of Science, vol. xxii. 



