464 On the Polarization of the Atmosphere. 



1844, August 26. — Barom. 2977 in., rising. Fine day. 



Apparent time. Arago. 



h m o< 



6 18 Neut. point among small mottled clouds. 29 ! 



1844, August 29.— Barom. 29*92 in., falling. Fine day. A 

 China-ink sky. Brewster's neutral point distinctly seen. 



2 20 R=l°4° maximum polarization in zenith plane. 



1844. September 21. — Barom. 30*1 in.; cold and clear sky. 

 6 16 R=28|° max. pol. in zen., 25|° in hor. 18 55 



Babinet. 



6 18 Polarization of moon 17£° .. 17 11 



1845, January 11. — Fine day, cold; wind west. 



Arago. 



2 10 R=28|° max. polarization in zenith. 8 15 

 1845, January 20. — Barom. 29-48 in. Fine day ; frosty. 



Mean time. Above horizon. 



3 10 R=29° maximum polarization in zenith. 



3 15 Alt. of Arago's neutral point . . 12 56 



ihj Alt. of Babinet's neutral point ; clouds 1 09 a 



\ came on . . . . j 



1845, January 24. — Barom. 29*55 in., rising. 



3 37 Alt. of Arago's neutral point . . 110 



3 59 Alt of Arago's neutral point . . 17 30 



4 4 Alt. of Babinet's neutral point . . 19 35 

 4 39 Alt. of Arago's neutral point . . 13 35 



4 41 Alt. of Babinet's neutral point . . 24 



1845, January 31.— Therm. 18° at 10 h p.m. of the 30th; 8 h 

 a.m., therm. 12°. Barom. 29*54 in., rising. Fine frosty, clear 

 day; ground covered with snow. 



12 55 R=26^° in zenith and in horizon. 



12 55 Arago's neutral point in N. hor. ; sun's alt. then 14° 45'. 



1 40 Arago's neutral point still in horizon. 

 1 40 R=26| in zenith. 



1845, February 1. — Barom. 29*80 in. Frosty day; cloudy 

 till 3\ 



3 30 Alt. Arago's neutral point . . 8 15 



R=20|° max. pol. in zenith to 14i° in hor. 

 3 45 Alt. Arago's neutral point . . 14 30 



R=22^° maximum polarization. 



1845, April 8.— Barom. 29*06 in. 



5 35 Alt. Arago's neutral point , . 9 10 



6 1 „ .. .. 20 20 



5 39 Alt. Babinet's neutral point . . 25 10 



6 4 „ .. .. 15 25 



