of the Atmosphere. 



297 



At this hour the curious phenomenon shown in the annexed 

 figure was seen, two hyperbolic neutral lines meeting in the sun. 



fc-f 



Fig. 2. 



+ J 



Mean time. 

 h in 



6 42 



7 50 



8 28 



9 10 

 9 30 



6 45 



7 30 



7 35 



8 20 



8 23 



9 10\ 

 9 30/ 



R= 27 h° maximum polarization. 



Faint clouds near 



Babinet's neutral point 

 above sun. 



13 24 

 26 37 

 15 16 

 20 24 

 15 



Arago. 



19 50 



20 25 



21 10 



f22 6 

 \23 41 



1841, June 9. — Barom. 20/9 in. Fine day ; mackerel sky oc- 

 casionally. 



Babinet. 



Fine pure sky. R=25|° in N. horizon. 5 



12 

 R=26|° + in zenith and horizon . 



Fine cirri above the sun 

 R=28i° in zenith and horizon 



Antisolar point below horizon. 



At 8 h 40 m clouds suddenly covered the whole horizon. 



1841, June 10. — See Philosophical Magazine, vol. xxx. pp. 

 121 & 162. 



* During the preceding quarter of an hour a stratum of cirri surrounded 

 the neutral point, and was just absorbed when the observation was made. 



3 55 



4 30 



6 30 



7 7* 



7 301 

 7 37/ 



8 



8 40 



7 45) 



7 54V 



8 21 j 



10 7 



