138 PLnrr's nattieal histobt. [Book II 



the autumn*; that everything is soothed by oil, and that 

 this is the reason why divers send out small quantities of it 

 from their mouths, because it smoothes any part which is 

 rough^ and transmits the light to them ; that snow never 

 falls in the deep part of the sea^ ; that although water gene- 

 rally has a tendency downwards, fountains rise up^, and that 

 this is the case even at the foot of JEtna^, burning as it does, 

 so as to force out the sand like a ball of flame to the distance 

 of 150 miles ? 



CHAP. 107. — THE WONDEES OF FIEE AND WATEE UNITED. 



And now I must give an account of some of the wonders 

 of fire, which is the fourth element of nature ; but first those 

 produced by means of water. 



CHAP. 108. (104.) — OF MALTHA. 



In Samosata, a city of Commagene*', there is a pool which 

 discharges an inflammable mud, called Maltha^. It adheres 



be longer in becoming raised or depressed than any particxilar portion 

 of the land, where contemporary observations may be made. 



1 The evaporation that is going on during the heats of summer, and 

 the heavy rains which in many coiuitries fall during the autumn, may 

 produce the effects here described, in confined seas or inlets. 



2 The statement is true to a certain extent, as is proved by the well- 

 known experiments of Franklin and others ; but the degree of the effect 

 is considerably exaggerated. See the observations of Hardouin, Brotier, 

 and Alexandre ; Lemaire, i. 450, 451. 



3 In the Mediterranean the warm vapours rising from the water and 

 its shores may melt the snow as it descends ; but this is not the case in 

 the parts of the main ocean which approach either to the Arctic or the 

 Antarctic regions. 



* The theory of springs is well understood, as depending upon the 

 water tending to rise to its original level, so as to produce an eqmhbrium 

 of pressure. 



5 When we consider the great extent of the base of ^tna, and that 

 the crater is in the form of an inverted cone, we shall perceive that there 

 is ample space for the existence of springs in the lower part of the moun- 

 tain, without their coming in contact with the heated lava. 



6 Samosata is situated on the Euphrates, in the north of Syria. 



7 The Petroleum or Bitumen of the modem chemists ; it is a tarry 

 substance, more or less fluid, which has probably been produced by car- 

 bonaceous matter, as affected by heat or decomposition, below the sur- 



