Study of the New York Obelisk as a Decayed Boulder. 161 



Specimens tested. 



A 

 B 

 C 

 D 



Fresh granite, Syene quarry 

 Decayed granite, Syene quarry 

 Fresh granite, Obelisk in 1881 

 Decayed granite, Obelisk in 1885 



Dried 

 cube. 



28.539 

 68.183 

 82.415 

 32.735 



Cube 

 moistened 

 by lateral 

 absorption. 



28.586 

 68.365 

 82.483 

 32.792 



Cube 

 saturated 

 by immer- 

 sion. 



28.595 

 68.436 

 82.640 

 32.886 



Cube in 

 distilled 



water 

 at 25° C. 



17.770 

 42.755 

 51.193 

 20,513 



From these weights the following coefficients have been calcu- 

 lated ; a and h, in percentage of weight of the rock : c, d, and e, in 

 percentage of its volume : and / and g, in percentage of its Total 

 Voids. 



Determinations of Absorption of Syene Granite, 

 fresh and decayed. 



I have long hoped to confirm and develop these results, by similar 

 experiments on a more extended series of specimens of granite from 

 Syene, for which I have been waiting. These were to include, 

 especially, specimens of fresh rock, to be reached by blasting from 

 some depth below the present surface in the quarries. On these, 

 chemical analyses were also to be made. But the recent death, in 

 the midst of his own useful investigations, of the friend, Mr, F. 

 Cope Whitehouse, on whose offered assistance I relied to procure 

 this material from Egypt, has decided me to publish at once the 

 results so far obtained. 



22, The causes and progress of the decay of the Obelisk. 



From the foregoing figures the following conclusions, I think, 

 may be safely drawn, even from this limited series; though we 



