65 



dark limb, and the brush of light were only partially visible in his 4 

 feet Fraunhofer, with a yellow screen glass, having a slight tint of 

 green. He saw them distinctly in the 3| feet Dollond, with a red 

 screen glass, used by Prof. Henry, for some four minutes after the 

 rupture of the ring, though none was visible in the Fraunhofer tele- 

 scope ; at least none is recollected to have been seen, though he ex- 

 amined the sun in the direction in which the ring broke. The testi- 

 mony of so experienced an observer, who, in examining this arch and 

 brush of light, used, interchangeably, the yellow and red screen 

 glasses, in favour of their far greater visibility through the red screen 

 glass, appears to be conclusive on the subject. This remarkable cir- 

 cumstance, not hitherto noticed in European observations, and first 

 suggested by Robert Treat Paine, Esq., from his observations at 

 Washington, appears to be now confirmed. It is one of great im- 

 portance ; as it seems to furnish evidence of the existence of a lunar 

 atmosphere, through which, as through our own, the red rays have 

 the greatest penetrative power. It also leads to new views concern- 

 ing the cause of the remarkable appearances of the beads of light, 

 and the dark lines frequently noticed; since it shows that their ap- 

 pearance may be completely modified by a change in the colour, and, 

 consequently, in the absorbing power of the screen glass through 

 which they are observed. 



The fact, noticed by most of the observers, that before the forma- 

 tion and after the breaking of the ring, the edge of the moon off the 

 sun was distinctly visible, and illuminated for some distance within 

 the moon's surface, is just such as would be presented by ^..twilight 

 caused by a lunar atmosphere; nor does there seem to be any other 

 plausible explanation of this phenomenon. 



The Committee on Prof. Henry's paper, entitled " Contribu- 

 tions to Electricity and Magnetism, No. 3. On Electro-dy- 

 namic Induction," reported in favour of publication, and the 

 Report was adopted. 



The Committee on Dr. Hare's papers, entitled, 1. " Rotary 

 Multiplier or Galvano-motive needle;" 2. "Apparatus for 

 showing on a large scale the Decomposition and Recomposi- 

 tion of Water by Galvanism;" 3. " Improved Process for Po- 

 tassium," reported in favour of publication, and the Report was 

 adopted. 



