Mr. Harvey on the Formation of Mists. 



59 



With respect to the observations contained in the last table, it 

 may be observed, that one of the conditions necessary to the 

 formation of mist in abundance over the sea, according to 

 the author of the paper before quoted, is the degree in which 

 the temperature of the water exceeds that of the air ; and it 

 is not improbable but that the excess of the temperature of 

 the land above that of the sea, the temperature of the atmosphere 

 reposing on each being precisely the same, was the cause which 

 led to the rapid passage of the mist from the sea to the land, 

 as observed at the commencement of the observations. 



For several of the latter days of August, some fine masses of 

 moving mist were observed, early in the evening, floating over 

 the sheets of water, and other moist places in the marshes be- 

 fore alluded to. On the 27th, between eight and nine, a beau- 

 tiful stratum of it was seen hovering over a part of the stream 

 which supplies the town with water. The mist moved in the 

 direction of the running stream, but with a velocity much 

 greater. It also accommodated itself in a most singular man- 

 ner, in its course, to all the turns and windings of the channel. 

 The breadth of the moving column was nearly the same as that 

 of the stream, and its average altitude about five feet. The 

 following observations were made on it. 



