And indeed who can be mistaken as to the fact, that all springs are colder in summer than in winter[683], as well as these other wonderful operations of nature; that copper and lead sink when in a mass, but float when spread out[684]; and of things that are equally heavy, some will sink to the bottom, while others will remain on the surface[685]; that heavy bodies are more easily moved in water[686]; that a stone from Scyros, although very large, will float, while the same, when broken into small pieces, sinks[687]; that the body of an animal, newly deprived of life, sinks, but that, when it is swelled out, it floats[688]; that empty vessels are drawn out of the water with no more ease than those that are full[689]; that rain-water is more useful for salt-pits than other kinds of water[690]; that salt cannot be made, unless it is mixed with fresh water[691]; that salt water freezes with more difficulty[692], and is more readily heated[693]; that the sea is warmer in winter[694] and more salt in the autumn[695]; 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[696] and transmits the light to them; that snow never falls in the deep part of the sea[697]; that although water generally has a tendency downwards, fountains rise up[698], and that this is the case even at the foot of Ætna[699], 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 WONDERS OF FIRE AND WATER 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[700], there is a pool which discharges an inflammable mud, called Maltha[701]. It adheres to every solid body which it touches, and moreover, when touched, it follows you, if you attempt to escape from it. By means of it the people defended their walls against Lucullus, and the soldiers were burned in their armour[702]. It is even set on fire in water. We learn by experience that it can be extinguished only by earth. CHAP. 109. (105.)—OF NAPHTHA. Naphtha is a substance of a similar nature[703] (it is so called about Babylon, and in the territory of the Astaceni, in Parthia[704]), flowing like liquid bitumen. It has a great affinity to fire, which instantly darts on it wherever it is seen[705]. It is said, that in this way it was that Medea burned Jason’s mistress; her crown having taken fire, when she approached the altar for the purpose of sacrificing[706]. CHAP. 110. (106.)—PLACES WHICH ARE ALWAYS BURNING.