90 Dr. Lathrop’s account of the effects of lightning. 
dently from east to west. The hardest thunder in Boston was 
about a quarter past seven; at Providence the hardest was about 
eight ; at Newhaven the severity of the storm came on about oné 
in the morning, as appears from the account published soon after. 
If it be a fact, that the thunder passed from east to west, while 
the wind in the lower region of the atmosphere was in the oppo- 
site direction, it will be natural to inquire for the cause. The 
following thoughts occurred to me, which are humbly submit- 
ted. ‘The wind, which had been many hours strong from the 
south and west, must have puta large portion of the atmosphere 
in motion towards the east. The re-action, not only condensed 
the vapors in the eastern region, forming the clouds, which gave 
plentiful showers of rain; but the same re-action, which the body of 
the atmosphere, moving from the west, received from the opposing 
body of the atmosphere at the east, must necessarily give a different 
direction to the wind, probably turning the current upwards, where 
there would be less resistance, and thus, in a higher region, forming a 
current of air, from east to west. |The longer the wind below shall 
continue to blow from the west, the farther, on the present supposi- 
tion, must the upper current proceed from the east. While two such 
currents of air continue, one below and the other above, carrying with 
them all the materials for thunder, there will no doubt be frequent 
explosions from clouds passing at no great distance from each other» 
When certain tracts of cloud in the upper current are ina positive 
state, the explosion will be toa negative state in the lower current. 
When tracts of cloud in the lower current are positive with respect to 
the earth, the discharge will be to the earth. _ When certain tracts of 
the earth are positive with relation to the clouds above, the discharge 
will be from the earth to the clouds. 
