of the Atmosphere. 

 1842, February 15. — Bain in morning, then fine day. 



349 

 Wind 



west*. 



Apparent time 

 h m 



4 25 

 4 44 

 4 55 



Babinet. 



R = 2/|° in zenith to 22^° inS.E. hor. 



21 58 



20 24 



wind west. 20 30 



Barom. 30'05 in., therm. 43 c 

 Clouds came into S. horizon at 4 h 55 m , and the whole of the N. 

 and N.E. horizon, especially above the sea, was covered 6° or 

 8° high with a dark band of distant haze. 



N.B.— At 3 h 48 m , when the 

 neutral point was 1° 57' high, 

 there was just above the sea-hori- 

 zon, H H, a portion m n of + 

 bands, a continuation of those on 

 the sea, so that there were two 

 neutral points here. These were 

 more fully developed at 3 h 58 m , 

 as shown in a former paper f. 



1842, February 16.— Barom. 

 30-16 in. % 



At noon, sun's alt. 21°, there 

 is clearly a faint neutral point a 

 little above the horizon, and 19° 

 below the sun. 



At 2 h 48 m , though the bands 

 at Arago's neutral point are all + , 

 as in fig. 4, they are most weak- 

 ened at m n, which is the effect of 

 the secondary cause. R = 19^° in 

 zenith, and in both horizons at 

 25° alt. 



At 3 h 10 m , the weak polarization 

 at ran now extends down to H H. 

 R = 22J° in zenith, and in horizon 

 at 25° alt. 



Fig. 4. 



Fig. 5. 



VX- 



H= 



At 3 h 44 m the two neutral points 

 are developed as in the annexed 

 figure, the — bands xx being just 

 distinctly visible. 



1842, February 18,— See Phil. 

 Mag. vol. xxx. pp. 123, 167. 



* See Phil. Mag. vol. xxx. pp. 123, 163. 



" xxx. p. 128. % Ibid. vol. xxx. pp. 123, 167. 



H 



Hi 



WSrSea 



+ Ibid. vol. 



