68 LIGHT SCIENCE FOR LEISURE HOURS. 



been consulted, and when the time of the transit came 

 she declined to enter upon or leave the sun's face in 

 the manner suggested by the astronomers. Consider, 

 for example, her conduct when entering on the sun's 

 face : 



At first, as the black disc of the planet gradually 

 notched the edge of the sun's disc, all seemed going on 

 well. But when somewhat more than half of the 

 planet was on the sun's face, it began to be noticed 

 that Venus was losing her rotundity of figure. She 

 became gradually more and more pear-shaped, until at 

 last she looked very much like a peg-top touching with 

 its point the edge of the sun's disc. Then suddenly 

 ' as by a lightning flash,' said one observer the top 

 lost its peg, and then gradually Venus recovered her 

 figure, and the transit proceeded without further change 

 on her part until the time came for her to leave the 

 sun's face, when similar peculiarities took place in a 

 reversed order. 



Here was a serious difficulty indeed. For when 

 was the moment of true contact ? Was it when the 

 peg-top figure seemed just to touch the edge of the 

 sun ? This seemed unlikely, because a moment after 

 the planet was seen well removed from the sun's edge. 

 Was it when the rotund part of the planet belonged to 

 a figure which would have touched the sun's edge if 

 the rotundity had been perfect elsewhere? This, 

 again, seemed unlikely, because at this moment the 

 black band connecting Venus and the sun was quite 



