418 



Observations 

 iin thunder 

 storms, &c. 



01? THUNDER STORMS. 



may form volumes of hydrogen and oxigen, which explode 

 upon the next discharge of an electrified cloud. 



If a thunder storm at a few miles distance be obser/ed when 

 the rest of the sky is tolerably clear, a quantity of white clouds, 

 the bottom of them flat, but arched on the top, (owing, pro- 

 bably, to the resisJance of the atmosphere against their ris- 

 ing, supposing them to contain the mixed gases, which are 

 lighter than the common air of the atmosphere), will be seen 

 floating above, and at the sides of the mass in which is the 

 storm ; by observing these white clouds attentively, some of 

 them \vill be seen suddenly to become dark, and soon after 

 to unite in the general mass. In this case, it appears that 

 u partial explosion of the gases contained in those clouds must 

 have taken place. 



If thunder were caused merely by the discharge of an 

 electrified cloud, and not by the gases exploding, the hea- 

 riest clap would always attend the largest and most vivid 

 flash of lightning ; but that is not the case, for a small clap 

 of thunder frequently follows a large flash of lightning. 



When the lightnitvg takes an horizontal direction, there is 

 freqi^ently either no thuader, or a ve?y small clap ; but when 

 it takes a perpendicular direction, the thunder is the hea- 

 viest. This is probably owing to the gases, which are formed 

 during the storm, being collected above in considerable quan- 

 tities. When 1 mention the lightning taking these different 

 directions, I do not mean the electrical fluid, which appears 

 blue, and freque^ntly in a zig zag form, but that reddish 

 light which surrounds it, and which has the appearance of 

 a shadow, and may be frequently observed to extend to a 

 great distance from the blue light, arvd which I conceive to fee 

 the gases in the act of exploding. 



From the number of clouds that join the storm, the gases 

 must frequently be in detached portions; and, when several 

 of them are fired nearly at the same time, the explosions, 

 will be heard in several distinct claps, which may be observed 

 in almost every thunder storm. 



In hot weather, when it is rather windy, lightning is fre- 

 quently observed unaccompanied by thunder; in this case^ 

 it appears that the wind has cither blown the mixed gases 

 abrosul, or prevented their union. 



From 



