314 ACCOUNT OF THE ERECTION OF A GRANITE 



means taken, for insuring a true horizontal surface, for the base 

 of the shaft ; but its stability entirely depended, on equal accu- 

 racy, in the surface of its receptacle, on the summit of the pe- 

 destal ; and seeing no mode by which, with their rude instru- 

 ments, this object was to be attained, I so far departed from 

 my first intention, as to offer them a spirit-level, and instruc- 

 tions for its use. They quickly understood and admired the 

 contrivance, but were afraid of venturing on new methods ; 

 their own was fas they affirmed) more slow, but equally cer- 

 tain, and they invited me to inspect it. The surface was rub- 

 bed clean and dry, and some water was dropped on it ; the 

 water ran ! " You see" (said the engineer) " the high and the 

 " low." He dried up the water, and applied the chisel to the 

 higher portion of the surface, and, by the patience and perse- 

 verance of several days, the surface was perfectly polished, and 

 a drop of water remained stationary wherever it was placed. 



The whole obelisk received a very fair degree of polish from 

 corundum. A piece of plank is overspread with the sort of ce- 

 ment, used for setting sword-blades in their handles : while this 

 substance is still liquid, it is mixed and powdered over, with 

 pulverised corundum, (reduced to a coarse or fine sand, ac- 

 cording to the purpose for which it is intended), and left to 

 dry in the sun. These planks, weighted over, are then used, 

 like the slabs of the stone-polisher in England. The knife- 

 grinders wheel, as you probably know, is made of the same 

 materials. 



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