102 Study of the New York Obelisk as a Decayed Boulder. 



from each edge up to a central line; but the opposite (W.N.W) 

 face appears to be plane and its edges straight. The exact determi- 

 nation of this point could not be well carried out from my unsteady 

 position in a swinging boatswain's chair. 



A corresponding curvature or entasis has already been noticed in 

 several Egyptian obelisks. In the northern erect Obelisk of Queen 

 Hatasu at Karnak, a decided convexity of at least one of its faces 

 was observed by Yerninac St. Maur.' In the Obelisk of Thothme- 

 ses III, now in front of the Church of St. Giovanni in Laterano, 

 at Rome, of which the shaft is 105 feet 7 inches in height, the 

 western face is slightly convex, and the pyramidal finish at the top 

 has a small convexity on each of the four sides. ^ But the best 

 known and most marked entasis occurs in the two obelisks of 

 Luxor (of which the western is now at Paris). In each, the N.W. 

 and S.E. sides are convex, to an extent of 030 and 0.035 meter^ 

 respectively (1^ and 1^ inches), at the middle of the rounding, 

 measured from a straight line across from edge to edge. In regard 

 to the object of this curvature, Wilkinson states:* " The faces, par- 

 ticularly those which are opposite to each other, are remarkable for 

 a slight convexity of their centres, which appears to have been 

 introduced to obviate the shadow thrown by the sun, even when on 

 a line with a plane surface. The exterior angle thus formed, by the 

 intersecting lines of direction of either side of the face, is about 3° " 

 Both the Luxor obelisks, however, have also a longitudinal curva- 

 ture of the same two faces, amounting to 0.020 and 0.045 meter 

 respectively, in the Paris Obelisk, that on the N.W. face being con- 

 vex and that on the S.E. concave. Hence all their longitudinal edges 

 are convex to the N.W., i.e., toward the Nile, By Prof. Donald- 

 son^ these curvatures are looked upon merely as defects in quarry- 

 ing, as he states: "I imagine that the first block must have been 

 irregularly marked out and worked, and the second one compelled 

 to follow the faulty line in the quarry," 



In regard to this feature in the New York Obelisk and those of 

 Luxor, I think it probable that at least longitudinal curvatures, 

 especially if with corresponding concavities on opposite side of the 

 blocks, may be but instances of tendency to curvature in splitting, 

 commonly observed in natural joints of granite and on the longer 



^ Gorringe, idem, 121. 2 Long, idem, 336. 



3 Lebas, idem, 63. * General View of Egypt, 167. 



' Parker, idem, 33. 



