]Q§ °N ATMOSPHERIC PHENOMENA. 



IV. 



Extract of a Letter from Mr. J. B. van Mons, Member of 

 the Institutes of France and Holland, to the Editor, on 

 Atmospheric Phenomena. 



SIR, 



Formation of JLN a paper which I laid before the Batavian Society of 

 thunderstorms. Experimental Philosophy at Rotterdam, I showed, that 

 thunder storms form in the atmosphere spontaneously, and 

 wholly. The diminution of sidereal, and particularly of 

 lunar attraction, suffers the air to sink down, by depriving 

 it of the additional elasticity this attraction imparted to it ; 

 this sinking loosens the union between the air and water; 

 the temperature is raised by the separation of the caloric, 

 Clouds. that served as the medium of this union ; and the water se- 



parates in some part or other of the atmosphere, forming a 

 cloud. This cloud soon enlarges by the continuation of the 

 same cause, the caloric separates from it in gre«t abun- 

 dance, and, as the air is a very bad conductor of heat, this 

 .can neither diffuse itself, nor be dissipated in the form of 

 light, a modification of caloric into which it is not suffici- 

 ently concentrated to transform itself, adopts the state of 

 electric fluid, and decomposes the water of the cloud. 

 Water convert ^ 1S probable, that this effect happens only to a very 

 c.l im.o a per slight quantity of caloric ; and that the portion of this prin- 

 ealoricirfa y c *P' e » which in combination with air serves to convert water 

 state approach- into a permanent gas, is contained in this union in the state 



fog to that of f e iectric fluid, or at least in a state intermediate either to 

 electric fluid, 



that or heat and electricity, or of electricity and light ; 



which fourth state bring incapable of subsisting except in 



combination, will never be known to us separately, or 



which is the otherwise than by its effects. This state is the agent, by 



'J.^,!!^ ,?««c means of which permanent gasses retain their state. With 

 nianeni g«sses. * ^ 



the bases of these gasses it enters into a chemical union, 

 which can be broken only by an affinity of the same na- 

 ture. 



Different states Caloric alone cannot convert these bases into gas, before 

 of caloric. 



