58 Mr. Harvey on the Formation of Mists. 



the ground, and covered by a glass plate, which rested on its 

 bulb; also of a thermometer placed on the upper surface of the 

 glass, and likewise a thermometer placed in the focus of a 

 thermoscope. The general circumstances of this night were 

 apparently the same as those of the 27th of April, at least the 

 deposition of dew and the clearness of the atmosphere bore a 

 strong resemblance to it ; still no mist was perceived, the tem- 

 perature of the atmosphere having in no case fallen below the 

 temperature of the ground. 



On the 13th of June, at 5f P.M , a mist began to form on 

 the sea, and in a short time it rapidly extended itself over the 

 land. The following observations were made of the tempera- 

 tures of the air and land. 



The mist appeared the greatest at the time the first tempera- 

 ture was determined, which was about half an hour after it was 

 first observed. Its density diminished during the two succeed- 

 ing observations ; and it will be found from an inspection of 

 the above table, that the excess of the temperature of the ground 

 aiove that of the air likewise decreased. At half-past nine, the 

 mist was changed into gentle rain, the thermometer at the same 

 time indicating only a difference of a single degree. During the 

 night, it appears, from the maximum degrees of cold, that the 

 register thermometer in the air was half a degree higher than 

 that on the grass. 



At the time the temperature was first observed on the land 

 a simultaneous observation was made by a friend, on the sea, 

 and the results were the following : 



