50 ON THE ANTIQUE HOUK-LINES. 



other. The section of the same undulated cone bv a cv- 

 lindrical surface, is seen in figure 10th. 



Figure 5th y Is the right section of the undulated cone which 

 contains the second antique hour-line B, and tenth I. The 

 section, by a cylindrical surface, is seen at figure 11th. 



Figure 6th, Is the right section of the undulated cone which 

 contains the third antique hour-line r, and ninth 0. Its 

 section, by a cylindrical surface, is figure 12th. A per- 

 spective and shaded view of this undulated conical sur- 

 face is figure 9. 



Figure 1th, Is the right section of the undulated cone which 

 contains the fourth antique hour-line A, and the eighth H ;. 

 figure 13th is its section by a cylindrical surface. 



Figure 8th, Is the right section of the undulated cone which 

 contains the fifth antique hour-line E, and the seventh Z. 

 Figure 14th, is its section by a cylindrical surface. 



Perspective and shaded view of one of the Surfaces, figure 9th'.. 



Figure 9th, Is a perspective and shaded view of the undulated 

 conical surface which contains the third antique hour-line 

 T, and ninth ; the point of sight is in the plane of the 

 equator, and the distance of the eye is two diameters from 

 the centre of the sphere ; in this view only one of the two 

 opposite surfaces is drawn. The right section of these 

 opposite cones is figure 6th, and their section by a cylin- 

 drical surface is figure 12th. 



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