244 Natural History of Volcanos and Earthquakes. 



e = 77028 inches of a column of mercury, or -^g- =2751 atmos- 

 pheres, and -Kg- gives the same number. On the other hand, 



for a constant increase of temperature of 1° F. in 57.1 feet it ad- 

 vances to a depth of 105627 feet below the surface of the sea, 

 where the corresponding temperature would be 1831°. 5 F. ;* for 

 the same formula gives e= 92435 inches of a column of mercury, 



] 05627 

 or 3301 atmospheres, when t =1881°.5, and - .^^ - gives the 



same value. Presupposing the correctness of the premises, these 



calculations shew the possibility of columns of lava of —^- = 



105627 

 29348 and -^ — =35209 feet being raised by the power of 



steam from the respective depths of 88044 and 105627 feet below 

 the surface of the sea, whilst there is an uninterrupted communi- 

 cation between the sea and the volcanic focus. The difficulty 

 mentioned by Gay-Lussac, that the water would, under its own 

 pressure, take the gaseous form before reaching the strata, which 

 are at white heat ; without being able to raise the lavas, to cause 

 earthquakes, and to support the volcanic phenomena ; is conse- 

 quently also set aside, in so far that the water cannot assume the 

 form of gas under its own pressure before reaching those depths 

 and their corresponding temperatures. At depths greater than 

 88044 or 105627 feet below the surface of the sea, if the commu- 

 nication with the sea remained free, a reaction would take place 

 in the column of water. Perhaps the phenomena mentioned in 

 Chap, xi, on Hot and Mineral Springs, vol. xxiii, of Ed. New 

 Phil. Journal, and observed by Horner near the Kurile Islands^ 

 as well as the powerful stream of hot steam, observed by Hoff- 

 mann near Vulcano,-\ beneath the surface of the sea, probably at 

 the same place where the crater of the cone formerly thrown up 

 at this spot was situated, proceeds from a similar volcanic effer- 

 vescence. In general, the rising of smoke from the sea during the 

 eruptions of neighboring volcanos is by no means an uncommon 

 occurrence. J The reflux and the internal agitation of the sea is 



* To simplify the calculation, I have supposed the mean temperature of the 

 surface = 32° F. t Loco cit. p. 67. 



X D. Curbetto (Von Buch loco cit. p. 78) observed a great quantity of smoke and 

 flames (?) accompanied with tremendous detonations, rise from the sea near Lan- 

 cerote, during the volcanic eruption on that island. Fish and pieces of pumice 

 were seen floating about. Several examples of this sort are cited farther on. 



