138 
PLINY'S IjrATirBAL HISTOBY. 
[Book II 
tlie autumn^ ; that everytliing is sootlied 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 ^tna^, 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 WOI^DERS OE TIEE AKD WATER TJKITED. 
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.) — OP 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 particular portion 
of the land, where contemporary observations may be made. 
1 The evaporation that is going on dm-ing the heats of smnmer, and 
the heavy rains which in many comitries fall dm-ing 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 Frankhn 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 equilibrium 
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 modern 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- 
