198 COSMOS. 



ic transformation of rocks, the greater importance has been 

 acquired for the consideration of the waters impregnated with 

 gases and salts which circulate in the interior of the earth, 

 and which, when they burst forth at the surface as thermal 

 springs, have already fulfilled the greater part of their forma- 

 tive, alterative, or destructive activity. 



c. Vapor and Gas Springs, Salses, Mud Volcanoes, Naphtha 

 Fire. 



(Amplification of the Picture of Nature, Cosmos, vol. i., p. 221-22G.) 



In the General Representation of Nature I have shown by 

 well-ascertained examples, which, however, have not been 

 sufficiently taken into consideration, how the salses in the 

 various stages through which they pass, from the first erup- 



the average is demonstrably heightened by the heat of the earth. 

 Whatever the distribution of rain may be, these springs are in their 

 average wanner than the air all the year round (the alterations of 

 temperature which they exhibit in the course of the year are commu- 

 nicated to them by the soil through which they flow). The amount 

 by which the average of a meteorologico-geological spring exceeds the 

 atmospheric average depends upon the depth to which the meteoric 

 waters have sunk down into the interior of the earth, where the temper- 

 ature is constant, before they again make their appearance in the form 

 of a spring ; this amount, consequently, possesses no climatological in- 

 terest. The climatologist must, however, know these springs, in order 

 that he may not mistake them for purely meteorological springs. The 

 meteorologico-geological springs may also be approximated to the 

 aerial average by an inclosure or channel. The springs were observed 

 on particular fixed days, four or five times a month. The elevation 

 above the sea, both of the place where the temperature of the air was 

 observed and of the different springs, was carefully taken into ac- 

 count." 



After the completion of the elaboration of his observations at Mari- 

 enberg, Dr. Hallmann passed the winter of 1852-1853 in Italy, and 

 found abnormally cold springs in the vicinity of ordinary ones. This is 

 the name he gives "to those springs which demonstrably bring down 

 cold from above. These springs are to be regarded as subterranean 

 drains of open lakes or subterranean accumulations of water situated 

 at a great elevation, from which the waters pour down very rapidly in 

 fissures and clefts, and break forth at the foot of the mountain or 

 chain of mountains in the form of springs. The idea of the abnorm- 

 ally cold springs is, therefore, as follows : They are too cold for the 

 elevation at which they come forth ; or, which indicates the conditions 

 better, they come forth at too low a part of the mountain for their low 

 temperature." These views, which are developed in the first volume 

 of Hallmann's Temperaturverhdltniss&i der (uellen, have been modified 

 by the author in his second volume (s. 181-183), because in every 

 meteorological spring, however superficial it may be, there must be 

 some telluric heat. 



