222 COSMOS. 



ties for heat and by tlieir conducting powers. The hottest of 

 all permanent springs (between 203^ and 209°) are likewise, 

 in a most remarkable degree, the purest, and such as hold in 

 solution the smallest quantity of mineral substances. Their 

 temperature appears, on the whole, to be less constant than 

 that of springs between 122° and 165°, which in Europe, at 

 least, "have maintained, in a most remarkable manner, their 

 hivariabilitif of heat and inineral contents during the last 

 fifty or sixty years, a period ih which thermometrical measure- 

 ments and chemical analyses have been applied with increas- 

 ed exactness. Boussingault found in 1823 that the thermal 

 springs of Las Trincheras had risen 12° during the twenty- 

 three years that had intervened since my travels in 1600.* 

 This calmly- flowing spring is therefore now nearly 12° hotter 

 than the intermittent fountains of the Geyser and the Strokr, 

 whose temperature has recently been most carefully determ- 

 ined by Krug of Nidda. A very striking proof of the origin 

 of hot springs by the sinking of cold meteoric M'ater into the 

 earth, and by its contact with a volcanic focus, is afibrded by 

 the volcano of JoruUa in Mexico, which was unknown before 

 my American journey. When, in September, 1759, Jorullo 

 \was suddeidy elevated into a mountain 1183 feet above the 

 level of the surrounding plain, two small rivers, the Rio de 

 Cuitimba and Rio de San Pedro, disappeared, and some 

 time afterward burst forth ajjain, durinjf violent shocks of an 

 earthquake, as hot springs, whose temperature I found in 1803 

 to be 186°-4. 



The springs in Greece still evidently flow at the same places 

 as in the times of Hellenic antiquity. The spring of Erasinos, 

 two hours' journey to the south of Argos, on the declivity of 

 Chaon, is mentioned by Herodotus. At Delphi we still see 

 Cassotis (now the springs of St. Nicholas) rising south of the 

 Lesche, and flowing beneath the Temple of Apollo ; Castaiia, 

 at the foot of PhsedriadiB ; Pirene, near Acro-Corinth ; and 

 the hot baths of ^dipsus, in Euboea, in which Sulla bathed 

 during the Mithridatic war.f I advert with pleasure to these 



* Boussingault, in the Annales de Chimie, t. lii., p. 181. The spring 

 of Chaudes Aigues, in Auvergne, is only 176°. It is also to be observ- 

 ed, that while the Aguas Calieutes de las Trincheras, south of Porto 

 Cabello (Venezuela), springing from granite cleft in regular beds, and 

 far from all volcanoes, have a temperature of fully 206°'6, all the springs 

 which rise in the vicinity of still active volcanoes (Pasto, Cotopaxi, and 

 Tunguragua) have a temperature of only 97'~'-130°. 



t Cassotis (the spring of St. Nicholas) and Castaiia, at the Phaedriad;e, 

 mentioned in Pausanias, x., 24, 25, and x., 8, 9 ; Pirene (Acro-Corinth), 



