210 ANNUAL RECOKD OF SCIENCE AND INDUSTRY. 



56 days out of 170. This scries is of remarkable accuracy 

 and import, ami demonstrates that the zodiacal light is in 

 the plane of the ecliptic without sensible deviation there- 

 from. The meteorological observations consist of live years 

 of records at A.M., noon, and G P.M., near Kingston, Ja- 

 maica, West Indies. Among the remarkable phenomena he 

 notes rain from a cloudless sky for 13 consecutive hours. 



Professor Everett publishes in the Proceedings of the Bel- 

 fast Society a lecture delivered by him Jan. 22,1878, on Atmos- 

 pheric Electricity. lie sums up our knowledge as follows: 

 "There is no other meteorological element, except perhaps 

 the wind, that can compare with electrical potential for the 

 extent and suddenness of its variations. On some rare occa- 

 sions, with no assignable external cause, and notwithstand- 

 ing the mitigating action of the collector, which eases off all 

 sudden changes, the needle of the electrometer swings from 

 side to side with a violent trembling like that of a magnetic 



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needle in a strong field. As regards the variation of poten- 

 tial according to the season of the vear, all observations con- 



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cur in showing that the average strength of potential is 

 greater in winter than in summer, but the months of maxi- 

 mum and minimum appear to differ considerably at different 

 places. The chief maximum occurs in some one of the win- 

 ter months; the chief minimum occurs everywhere in May 

 or June ; the average potential in the strongest month is 

 about double of that in the weakest. As regards the varia- 



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tion of potential with the hour of the day, the Kew observa- 

 tions show a double maximum in the twenty-four hours. 

 The hours of maximum are, in July, 8 A.M. and 10 P.M. ; in 

 January, 10 A.M. and 7 P.M. ; and in the spring and au- 

 tumn, about 9 A.M. and 9 P.M. The few observations taken 

 during the recent Arctic expedition show that the general 

 features of atmospheric electricity were the same at the win- 

 ter-quarters of the Alert as they are in these temperate re- 

 gions." lie adds that our great want at present is balloon 

 observations, and suggests a method by which such can be 

 made. With regard to the origin of atmospheric electricity, 

 he says: "I feel convinced that friction either of the air it- 

 self or of the solid or liquid particles contained in it against 

 the surface of the earth is one cause of the generation of elec- 

 tricity in the air." 



