1 20 On Atmospheric Phcenomena. 



into a lower region, where it lose? its transparency and pre- 

 sents the appearance of a general mist, covering the sky, and 

 forming itself into small clouds, which keep augmenting 

 and joining the larger clouds in the lowest station, till suffi- 

 ciently increased to allow the electricity to strike to the di- 

 stance of the earth ; when it hegins to lighten, and the cloud 

 is precipitated in rain. But so sudden a condensation and 

 discharge must be accompanied with the formation of aa 

 extensive vacuum, and an instantaneous collapsina; of the sur- 

 rounding atmosphere ; a cause perfectly sufficient to account 

 for the noise of the accompanying thunder; for, if the dis- 

 charge of a large gun merely by the impulse of the gas ge- 

 nerated bv the explosion of the gunpowder, striking against 

 the atmosphere into which it is thrown, can produce so loud 

 a report, what proportion can so diminutive au eiTort be 

 made to bear with the large scale on which Nature performs 

 her processes? 



The fall of so large a mass of water as was before sus-r 

 pended in the atmosphere must, undeniably, leave its gravity 

 minus the weight of that mass. Accordingly the barometer 

 sinks immediately, and sinks even to a lower station than it 

 can maintain ; vi'hich shows, that though the atmosphere 

 collapsed to destroy the vacuum where the discharge took 

 place, still there is a want of atmosphere in that region, which 

 is gradually supplied from the neighboarhood, — (one of the 

 causes of winds.) As the cause of diminution of volume 

 in the atmosphere ceases, the barometer rises again ; and 

 when it has entirely ceased to operate, the barometer reaches 

 some intermediate point between its highest and lowest 

 level. 



That electricity is the principal suspending cause of clouds, 

 may be inferred from another circumstance. Clouds exist 

 permanent in regions of so low a temperature that water 

 could never reach them without being frozen ; or, if we sup- 

 pose a loss of heat to have taken place after the ascent of the 

 Tapour, how comes it then to be suspended, instead of de- 

 scending in snow ? This shows that there is a great diffe- 

 rence between cloud and vapour : the former being held in 

 its divided state by electricity may perhaps be denominated 



electrified 



