of the Atmosphere. 121 



olarization. Height of neutral point 



In horizon. above the antisolar point. 



very near the horizon 

 above and close to the horizon. 

 18 20 



20 30 



21 43 



1841, June 10, 2\ — Barom. 29' 7 in. Singularly fine sky all 

 day; wind east. When the neutral line or point of the polari- 

 meter happened to be above an illuminated wall, the effect was to 

 vary the place of the neutral point, as if the polarization of the 

 sky were diminished. At 3 h 47 m , when the sky was everywhere 

 pure and free of clouds, the neutral line of the polarimeter was 

 curved above the land horizon. At 6 h 32 m its curvature was 

 greater above the sea horizon, the deviation increasing towards 

 the horizon. 



1841, June 3. 







R= maxim 



Mean time. 



In zenith. 



h m 



o 



6 27 P.M 



Neutral p 



6 36 „ 



)> 



6 43 „ 



» 



7 8 „ 





7 35 „ 





8 4 „ 





8 33 „ 



The sun set. 



6 35 p.m 



. Neutral point in 



horizon. 





7 13 „ 







18 20 



7 50 „ 



28! 



28-| 



18 56 



7 42 „ 







21 



8 5 „ 



29! 



28± 



19 15 



8 18 „ 





29| 



18 56 



8 36 „ 



The sun set. 





19 25 



8 52 „ 



291 



30 



19 29 



1841, July 17.— Barom. 29'60 in. ; therm. 55°. Wind south- 

 west. A China-ink sky, with clouds here and there. 



7 35 p.m. 19 



8 „ 17 48 

 8 18 „ Sunset. 17 25 

 8 30 „ 17 45 



8 47 „ 17 19 



9 2 „ 16 15 

 9 J2 „ 17 26 

 9 22 ,. 19 7 



1841, August 31. — Rain till l h p.m., when it cleared up. 

 Barom. 29'7 in. 



5 44 p.m. 



27! 



18! 



17 22 



6 „ 



28! 



22! 



19 55 



6 20 „ 





. # 



19 59 



6 38 „ 





. , 



20 3 



