ATMOSPHERIC ELECTRICITY. \3$ 



intensity after contact, is greater, as the quantity of dew is 

 greater. 



XVII. The electricity of dew seems to be, in proportion to Dew acts near- 

 its quantity, in the same manner as the electricity of rain v llke rau ^ 

 depends on its quantity; and the peculiar manner or circum- 

 stances which attend the falling of the dew, influences the 

 electricity in the same way, as does the peculiar manner in 



which rain takes place. 



XVIII. As rain, showers, aurora borealis, zodiacal light; Succession of 

 have a tendency to begin afresh for several successive days, similar pheno* 

 with the same characteristic accidents, so the electricity of dew 



seems to have, as it were, an inclination to appear for several 



evenings successively, with like characters. 



After these propositions relating to the dew, father Beccaria An experiment 



adds the following : let the air, in a closed room, be electrified, of artificial 

 , . . , , ,./-,-,.•• dew in a room 



that 18 to say, the moisture and other vapours diflused in it -> let art ificiallyeleo 



a bottle filled with water, colder than the air of the room, and trified. 

 insulated on a stove of glass, be raised pretty high in the room, 

 and the insulation be carefully preserved. Then the electric 

 signs that will arise in two threads suspended to the bottle, 

 will exactly represent the electricity of dew, for they will 

 exhibit the different manners after which this electricity takes 

 place, according as the electrified vapours in the room are more 

 or less rare ; as the difference between the heat of the bottle, 

 and of the air in the room, is more or less ; and as the insu- 

 lation of the bottle is more or less accurate. 



This excellent and most industrious philosopher, after recit- 

 ing various facts respecting the electricity of dew, concludes 

 with the following summary observations : 



The diurnal electricity resembles the electricity of a very The diurnal 

 Tare fog, which rises, becomes dilated, and by that means, con- sembVe^tha^of 

 tinually renders the insulation more perfect. The nocturnal a fog, and the 

 •lectricity resembles that of a very rare and subtle rain, which n .'S ht elect "- 

 descends, becomes condensed, and continually renders the insu- »hower. 

 lation less perfect, whenever the diurnal electricity is more 

 constant. But the nocturnal electricity frequently fails, and 

 only attains its greatest intensity when the increase of that 

 moisture, which is the conductor of it, happens to take place 

 without injuring the insulation. 



Noticf 



