559 



both being to the left when the instrument was held parallel to a line 

 joining a part of halo to the left of the moon with the moon. 



October 10th, 1857. Polariscope applied to a prismatic luminous 

 haze round the moon, three diameters of moon's radius; slight polari- 

 zation, the image to the right hand being brighter, mark on eye-end 

 to left hand ; instrument held horizontal, looking at the haze to the 



right of the moon. 



Sun. 



March 18th, 1858. Prismatic halo round the sun's diameter 

 about 45, with two parhelia, one on each side of the sun ; instrument 

 applied to the left parhelion ; slight polarization, the outer or left 

 image being brighter when the instrument was held in a plane parallel 

 to a line joining the sun and parhelion, the eye-mark and brighter 

 image both to the left. 



May 15th, 1858. Prismatic halo round sun, diameter about 45, 

 with two parhelia, one on each side. The instrument held in same 

 azimuth as last observation, looking at left parhelion ; a little stronger 

 polarization, the outer image being brighter. 



May 25th, 1858. Appearances in neighbourhood of sun and par- 



A. Sun's altitude, 39 15'. B. Circle running round heavens, 101 diam. 



C. Circle 22 in radius, passing round A and intersecting B. 



D. A parhelion occurring on circle C. 



E. An oval arc, radius horizontally 27 30', perpendicularly 22, 



F. Parhelion occurring on circle C. 



G. Part of a circle passing through F, 17 15' above horizon. 



H and I. Two parhelia on horizontal circle (101 diameter), each distant from 

 sun 25 30'. 



VOL. X. 2 Q 



