Chap. 43.] 
OF THUNDER A.^D LIGHTFIT^a. 
69 
are the Suculse ; there is also Bootes, which follows the seven 
northern stars \ 
CHAP. 42. (42.) — OF TJNCEBTAIK STATES OF THE WEATHER. 
But I would not deny, that there may exist showers and 
winds, independent of these causes, since it is certain that 
an exhalation proceeds from the earth, which is sometimes 
moist, and at other times, in consequence of the vapours, 
like dense smoke ; and also, that clouds are formed, either 
from the fluid rising up on high, or from the air being com- 
pressed into a fluid^. Their density and their substance is 
very clearly proved from their intercepting the sun's rays, 
which are visible by divers, even in the deepest waters^. 
CHAP. 43. (43.) — OF THUlSrnER and LIGHTNIl^a. 
It cannot therefore be denied, that fire proceeding from 
the stars which are above the clouds, may fall on them, as 
we frequently observe on serene evenings, and that the air is 
agitated by the impulse, as darts when they are hurled whiz 
through the air. And when it arrives at the cloud, a dis- 
cordant kind of vapour is produced, as when hot iron is 
plunged into water, and a wreath of smoke is evolved. Hence 
arise squalls. And if wind or vapour be struggling in the 
cloud, thunder is discharged ; if it bursts out with a flame, 
there is a thunderbolt ; if it be long in forcing out its way, 
it is simply a flash of lightning^. By the latter the cloud is 
simply rent, by the former it is shattered. Thunder is pro- 
^ " Septemtriones." 
2 The doctrine of Aristotle on the nature and formation of mists and 
clouds is contained in his treatises De Meteor, lib. i. cap. 9. p. 540, and 
De Mundo, cap. 4. p. 605. He employs the terms drfik, re^os, and 
veipeKri, which are translated uajpor, nuhes and nebula, respeetiv ely. The 
distinction, however, between the two latter does not appear very clearly 
marked either in the Greek or the Latin, the two Greek words being in- 
discriminately appHed to either of the Latin terms. 
3 It is doubtfiil how far this statement is correct ; see the remarks of 
Hardouin, Lem. i. 320. 
* The words in the original are respectively fulmen and fulgetrum ; 
Seneca makes a similar distinction between fulmen dindifulguratio : " Ful- 
guratio est late ignis expHcitus ; fulmen est coactus ignis ot impetu 
jactus." Nat. Qusest. lib. ii. cap. 16. p. 706. 
