204 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



or other condensed gases in a highly heated state — that any accession 

 or diminution of heat, arising from the volcanic causes in operation 

 in the neighbourhood, will increase or diminish the elasticity of these 

 gases, and thus cause an elevation or subsidence in the strata above. 



82. A different view however of the effect of heat may be taken, 

 one which is well known, and which has in some instances been 

 measured. The solid beds below the temple are themselves liable 

 to expand by the action of heat, and to contract by its abstraction ; 

 rents and earthquakes, as well as elevations and depressions of the 

 surface, may be the result of the partial application of this cause. 

 It may perhaps be doubted whether sufficient effect can arise without 

 imagining masses of immense thickness to have altered their tem- 

 perature ; a change which might have required longer time for its 

 completion than the phoenomena admit. 



From a series of experiments upon the expansion of various stones 

 by the application of heat, made by Mr. H. C. Bartlett, of the U. S. 

 Engineers, under the direction of Col. Totten, and recorded in the 

 American Journal of Science, vol. xxii. p. 136, it appears that for 

 1° of Fahrenheit's scale* — 



Granite expands -000004825 



Marble -000005668 



Sandstone '000009532 



From these data the expansion of those substances has been cal- 

 culated for various degrees of temperature, and for thicknesses vary- 

 ing from 1 to 500 miles. The table is given in the Appendix. From 

 this it may be inferred, that if the strata below the temple and its im- 

 mediate neighbourhood are equally expansible with sandstone, then 

 a change of temperature of only 100° F. acting on a thickness of 

 live miles would cause a change of level of above twenty -five feet — 

 an alteration greater than any of the observed facts at the temple of 

 Serapis require. 



A similar change would be produced by supposing the temperature 

 of a bed one mile thick raised 500° F. ; and if the temperature of 

 a bed of such matter 2600 feet thick were raised 1000°, its surface 

 would be elevated by twenty-five feet. 



* Other experiments have since been made by Mr. Adie, of which an account is 

 given in vol. xiii. of the Trans, of the R. Soc. of Edinburgh. From this the fol- 

 lowing list of expansions are extracted : — 



Expands. 



Roman Cement, per 1° Fahr -00000750 



Sicilian White Marble -00000613 



Carrara Marble -00000363 



Sandstone from Craigleith Quarry., •000006.'i2 



Slate from Penrhvn, Wales -00000576 



Peterhead Red Granite -00000498 



Arbroath Pavement -00000499 



Caithness Pavement -00000497 



Greenstone from Ratho -00000449 



Aberdeen Grey Granite -00000438 



Best Stock Brick -00000306 



Fire Brick -00000274 



Black Marble, Galway -00000247 



dhe Ninth Bridgewater Treatise, p. 223, 2nd edit., 1838.) 



