116 On Atmospheric Phcenomena. 



tions to which I apply them. How far any of them are cor- 

 rect, lies not with me to determine. Should I only have 

 succeeded so far as to help any other person to do more jus- 

 tice lo the subject, my end will be fully gained. 



Observation I. When a thunder storm is gathering, small 

 specks of cloud mav be observed, which increase rapidly in 

 size ; and round about, in every clear part of the sky, others 

 may be seen forming, which all keep uniting till a very large 

 cloud is fornred, which is shown by the event to be well 

 charged with eljectricitv ; for sparks are soon after discharged 

 to the earth, the cloud collapses, drops of water are formed 

 by the approach and union of the moist particles, and a 

 heavy shower of rain falls from the cloud. But as it is well 

 known that bodies charged with electricity never part with 

 th& whole at one shock, so only a portion of the cloud 

 is thus thrown down, proportioned to the quantity of elec- 

 tricity previously given off. Other clouds still keep joining 

 the large one, another spark is emitted, and a second torrent 

 of rain follows. 



II. In fine weather, when the wind was easterly, I have 

 observed an effect quite the reverse of the foregoing, — large 

 clouds coming before the wind from about two miles di- 

 stance, which were constantly breaking in pieces and dis- 

 solving in the air, so as to disappear entirely before the wind 

 could bring them over my head. I have also been under 

 clouds that were thus gradually dissolved without being 

 followed by any thing like rain ; and when the clouds touch 

 the mountains I have seen them break and dissolve quickest. 



III. When this kind of weather had continued some davs, 

 and all clouds had disappeared, the sky was very pale, owing 

 to a mist in the air, vthich so obscured the distant moun- 

 tains that little more than their outlinecould be distinguished. 

 This proves that the air does not hold the water of the dissi- 

 pated clouds, or the vapours raised simply by heat, in solu- 

 tion ; for if so it would be perfectly transparent. (It is well 

 known by astronomers, that in frosty weather the air is clear- 

 est ; which is owing to the complete absence of all vapours 

 raised by heat only.) When clouds again appcarcdj first the 



sky 



