Q. _Why do we hear the collapsing of the air NEAREST the earth FIRST?_ A. Because sound takes a whole _second of time_ to travel 380 yards; but the air is ripped from top to bottom instantaneously: if, therefore, the cloud were 1000 yards off, we should hear the collapsing of the lowest strata nearly _three seconds_, before we heard that in the immediate vicinity of the cloud. Q. _Why is the THUNDER sometimes like a deep GROWL?_ A. When the storm is _far distant_, the thunder sounds like a deep growl. Q. _Does not SCENERY affect the sound of thunder?_ A. Yes; the _flatter_ the country, the more unbroken the peal: _Mountain_ scenery _breaks_ the peal, and makes it harsh and irregular. Q. _What is the cause of ROLLING THUNDER?_ A. The rolling is produced by the _reverberation_ of the thunder along the massive clouds. Q. _What is meant by the reverberation?_ A. The echo. Q. _Why is a flash of lightning generally followed by a POURING RAIN?_ A. The cloud _collapses_, as soon as the electric fluid has left it; and the water it contained is squeezed out. Q. _Why is a flash of lightning generally followed by a GUST of WIND?_ A. The flash _rent the air asunder_ through which it darted; and when the two parts collapse, a rapid motion is produced, which we call _wind_: the _vibration_ of the thunder contributes also to agitate the air. Q. _What is meant by the_ "VIBRATION _of the thunder_?" A. The quivering motion it gives to the air, by its loud sound. Q. _Why is there NO THUNDER to what is called SUMMER LIGHTNING?_ A. Because the lightning-clouds are _so far off_, that the sound of the thunder is _lost_, before it reaches the earth. Q. _Do_ THUNDER-BOLTS _ever drop from the clouds?_ A. No; the notion of _thunder-bolts_ falling from the clouds, arises from the _globular_ form, that is sometimes assumed by a flash of lightning. Q. _Why is the_ THUNDER _often several moments_ AFTER _the FLASH?_[1] A. The flash travels nearly _a million_ times faster than the thunder; if, therefore, the thunder has _far to come_, it will not reach the earth till a considerable time _after the flash_. [1] The speed of lightning is so great, that it would go 480 times round the earth in one minute: whereas, thunder would go scarcely 13 miles in the same space of time. Q. _Can we not tell the DISTANCE of a thunder-cloud, by observing the interval which elapses between the flash and the peal?_ A. Yes; the flash is _instantaneous_, but the thunder will take a whole _second of time_ to travel 380 yards: hence, if the flash is 5 seconds before the thunder, the cloud is 1900 yards off. (i. e. 380 × 5 = 1900 yards.) Q. _What PLACES are most DANGEROUS to be in, during a STORM?_ A. It is very dangerous to be near a tree, or lofty building; it is dangerous also, to be near a river, or any running water. Q. _Why is it DANGEROUS to be NEAR a TREE, or lofty building, during a thunder-storm?_