EARTHQUAKES. 175 



menon, and not the strength of the wave commotion which 

 has once passed through the solid parts of the earth, that 

 gives rise to the gradual and very important, but too little 

 considered enlargement of the circle of commotion?* 



Volcanic activities, of which the earthquake is one of the 

 lower grades, almost always include at the same time, move- 

 ment and the physical production of matter. In the Deli- 

 neation of Nature we have already repeatedly indicated that 

 water and hot vapours, carbonic acid gas and other mofettes, 

 black smoke (as was the case for several days in the rock of 

 Alvidras during the earthquake of Lisbon on the 1st Novem- 

 ber, 1755), flames of fire, sand, mud and moyas mixed with 

 charcoal, rise from fissures at a distance from all volcanoes. 

 The acute geognosist, Abich, has proved the connexion which 

 exists in the Persian Ghilan between the thermal springs of 

 Sarcin (5051 feet), on the road from Ardebil to Tabriz, and 

 the earthquakes which frequently visit the elevated districts 

 in every second year. In October, 1 848, an uiidulatory move- 

 ment of the earth, which lasted for a whole hour, compelled 

 the inhabitants of Ardebil to abandon the town ; and the 

 temperature of the springs, which is between 44 and 46 C. 

 (= 111 115 F.) rose immediately to a most painful 

 scalding heat, and continued so for a whole month. 22 As 

 Abich says, nowhere perhaps upon the face of the earth is 

 " the intimate connexion of fissure-producing earthquakes, 

 with the phenomena of mud- volcanoes, of salses, of combus- 

 tible gases penetrating through the perforated soil, and of 



21 Upon the simultaneous commotion of the tertiary limestone of 

 Cumana and Maniquarez since the great earthquake of Cumana on the 

 14th December, 1796, see Humboldt's Relation Historique, tome i, 

 p. 314 ; Cosmos, vol. i, p. 208, Bonn's edition ; and Mallet, Brit. Assoc. 

 Report, 1850, p. 28. 



^ Abich, on Daghestan, Schagdagh, and Ghilan, in Poggend. A nnalen, 

 Bd. Ixxvi, 1849, p. 157. The salt spring in a well near Sassendorf, in 

 Westphalia (in the district of Amsberg), also increased about l per 

 cent, in amount of saline matter, in consequence of the widely extended 

 earthquake of the 29th July, 1846, the centre of commotion of which 

 is placed at St. Goar, on the Rhine ; this was probably because other 

 fissures of supply had opened (Noggerath, Das Erdbeben im Rheinge- 

 biete vom 29 Juli, 1846, p. 14). According to Charpentier's observation, 

 the temperature of the sulphureous spring of Lavey (above St. Maurice, 

 on the bank of the Rhone), rose from 87.8 to 97.3 F. during the 

 Swiss earthquake of the 25th August, 1851. 



