XLV. By Jove the Etruscans meant, as we do, all that is greatest and best--Fate, Providence, Nature, the Universe 91 XLVI. He is the source of the thunder’s power, though he does not superintend each stroke. Why he spares the guilty is another affair, which will be discussed in another place 92 XLVII. An erroneous classification of thunderbolts according to time 92 XLVIII. It must be wrong, because the time is always limited. A better basis of treatment is that of Attalus. Place, time, person, etc., must all be looked into 93 XLIX. Caecina’s division, his names and their meanings 94 L. That of Attalus is much better, being based on the true signification 95 LI. The signification of some does not affect, of some does not reach, us 95 LII. The force of lightning as seen in different materials, and at different times in the same material (cf. xxxi.) 96 LIII. Poisonous effects: may be followed up afterwards. Panegyric on philosophy 97 LIV. Returns to Posidonius’ (Aristotle’s) opinion as to the cause of thunder, an explosion of air 98 LV. The collision of clouds may produce it. Air is the cause in this instance also. Shooting stars are associated with thunder, but this is the exception, not the rule 98 LVI. Heraclitus and Caecina think sheet lightning an intermittent incipient fire. Change in the pronunciation of the Latin word 100 LVII. Lightning is probably due to the air turning into fire through rarefaction of the clouds. It is naturally most frequent in summer. Sheet and forked lightning differ in degree, not in kind 100 LVIII. Reasons for rapidity of lightning and its obliquity 101 LIX. Every story should have a moral. Death cannot be prevented; why fear it? It is cowardly and silly. Death by lightning is rather an honour than otherwise. Besides, fear is futile 102 BOOK III ON FORMS OF WATER PREFACE