R= maximum 



polarization. 



Height of neutral point 



In zenith. 



In horizon. • 



above 



: the antisolar point. 



o 



29 









17 20 



27 



18| 





17 21 



. . 







18 25 



, , 







22 16 



14| 



. , 



"■ 



22 15 



126 Sir David Brewster on the Polarization 



The decrease in these numbers as the sun's altitude increased 

 is very interesting. The light of the sky was increasing till 

 noon, whereas, when the numbers increase, the light of the sky 

 diminishes. 



The observations on the 14th, 20th, and 21st of November 

 were the only morning ones I made. 



1842, December 28.— Barom. 29-56 in. Sky very fineatll h 38 m . 



Apparent time, 

 h m 



11 38 p.m. 



11 58 „ 



1 A.M. 



1 28 „ 



2 33 „ 



See the state of Babinet's neutral point at this date, when a 

 halo of 45° encircled the sun. 



1843, February 2. — Barom. 29*05 in. Snow-storm with wind. 



9 55 a.m. 2A\ \7i 



Polarization of the sun's light by the snow hardly per- 

 ceptible, whether we look towards or from the sun. 

 2 5 p.m. Neutral point in sea horizon. 12 5 



2 47 „ 26^ 19^ 14 35 



1843, February 14.— Barom. 29-45 in. Bitter cold day ; frost 

 in the morning. 



2 48 a.m. Neutral point below horizon. 12 5 



253 {r„t;r}28i 23J 1145 



1843, March 25.— Barom. 29*97 in. 



4 35 a.m. 25 Neutral point in horizon. 10 



5 15 „ .. .. 11 30 



5 44 „ 28 . . 18 31 



6 9 „ 29^ .. 17 30 



1843, June 21. — Barom. 2975 in. Fine day; wind west. 



7 12 a.m. m «{J^|»40| 



16 31 

 19 22 

 18 29 



1844, February 3. — Barom. 29*90 in. Snow covering the 

 ground. 



4 7 a.m. 26 23 18 20 



7 44 „ 



. . 



8 30 „ 



29 



9 16 „ 



30 



