M.-P.— Vol. I.] DAVIDSON— APPARENT PROJECTION, ETC. 83 



indeed it presented the appearance of 'Baily's beads' at 

 the time of a total solar eclipse. Its whole depth was one- 

 fourth of the planetary radius" ; and the published drawing 

 showed the broader part of the coronal light partly inside 

 the planet's circumference when the planet was half on the 

 Sun's disc. Astr. Nach. 2,481. Here we have exhibitions 

 of the same or a similar phenomenon at the same transit 

 under widely different atmospheric conditions; and the first 

 is surely to be taken as better representing the true or nor- 

 mal phase of the phenomenon, and the latter is to be 

 reckoned as abnormal and misunderstood. 



This, phenomenon of the so-called " atmosphere of 

 Venus," though not connected with the disturbance of our 

 atmosphere, is thus seen to be affected by it just as much as 

 the outline of Sun or planet. Mouchez has called it the 

 "pale aureole * * * to be attributed in part to the at- 

 mosphere of the Sun rendered visible by contrast, and also 

 in part by the atmosphere of Venus." Heraud and Bonify 

 designated it as the "filet lumineuse; ' : and Airy says this 

 "penumbra must, of course, be considered a part of 

 Venus;" and elsewhere he says "the partial illumination of 

 the atmosphere of Venus introduces difficulties of observa- 

 tion" etc. One observer says that this ring of light around 

 Venus enabled him to see the planet twenty-four minutes 

 before contact. One of our astronomers who had wit- 

 nessed the transits of Venus of 1874 ar, d 1882 asserts that 

 "there seems to be absolutely no way of escaping from a 

 new difficulty — the planet's atmosphere causes it to be sur- 

 rounded by a luminous ring — as it enters upon the Sun's 

 disc, and thus renders the time of contact uncertain by at 

 least five or six seconds." Another admits "the disturb- 

 ance of the image by irregular refraction in the Earth's 

 atmosphere," but declares that "we must look to the chief 

 cause of the great discordances" of the times of contact of 

 Venus and the Sun, "in the atmosphere which surrounds 

 Venus." And he further says, that "the cruel manner in 

 which all the phenomenon are modified by the atmosphere 

 of Venus is not easy to explain." Another declares "the 



