POLARISATION OF THE ATMOSPHERE. 25 ? 



1841, September 13. 



An 



g°- 



19° 



10' 



20 







18 



16 



18 







17 



27 



Mean Time. 

 5 h 55 ra A.M. R=25|° zenith; 2 3 |° horizon. 



5 58 



6 32 p.m. R= 251° zenith. 

 6 38 

 6 42 



1841, September 15.— Barom. 29-61. Splendid day. 



Mean Time. 

 10 h m a.m. R = 27 J° in zenith plane, and 25J° in horizon. 

 10 18 R=28£°. Maximum 88° from horizon. 



Arago. 

 6 p.m. 19° 54' 



6 8 18 18 



6 10 Sky not altogether pure. 18 47 



6 28 R=27|° in zenith plane. 18 5 



1841, September 21.— Barom. 29-95. Sky not pure ; an eastern haur for three 

 preceding days. 



Mean Time. Arago. 



4 h 50 m R=15|° in zenith, and 14° 30' ahove S. horizon. 



4 55 Sky whiter in zenith than in horizon. 21° 59' 



1841, September 23. — Barom. 2947. Air damp, but no rain. 



Mean Time. Arago. 



6 h 0™ p.m. R=26£° in zenith, and 17|° 15° alt. S. 13° 30' 



The sky impure. Neutral point covered with small black clouds ; an eastern 

 haur supervened. 



1841, September 26.— Barom. 29-25. Day showery. 



Mean Time. Arago. 



5 h 49™ p.m. R=22i° zenith; 26J in horizon. 22° 2' 



6 10 Not free of clouds about neutral point. 20 2 



6 15 The sky purer. 21 50 



1841, September 29. — See " Edinburgh Transactions," vol.xxiii pp. 215, 223. 

 1841, September 30.— Barom. 2903. 



MeaE 



Time. 



4 h 



27 m 



4 



37) 



4 



43 



4 



49 



R = 26° in zenith plane, and 25° 10° ahove S. 



horizon. 

 Sky whitish. (20° 20' 



Black cloud passed over neutral point. < 19 49 



I 22 29 



1841, October 3.— Barom. 29.8. Wind north-east; cold. 



Mean Time. Arago. 



4 h l m R= 27i° in zenith plane, and 26 J° above horizon. 



4 44 21° 15' 



A cloud passed, and the neutral point descended. 



