134 Study of the New York Obelisk as a DecoAjed Boulder. 



14, The sudden decay of the surface of the Obelisk. 



In regard to the condition of the surface of the New York Obe- 

 lisk, immediately after its arrival, there is the following testimony 

 by an experienced geologist,' in February, 18S3: " The first thing 

 that strikes one is the freshness and soundness of the rock. No 

 'maladie du granit' is observable, and this fact will answer the first 

 and natural question as to why this rock was so much preferred by 

 the Egyptians for monumental purposes." 



On thin sections from the same specimen, Prof. Alfred Stelzner' 

 also states, though with some confusion of the products of meta- 

 morphism with those of decay : " The microcline . . . is very fresh 

 and free from interpositions. . . . Secondary formations are almost 

 entirely wanting in the sections before me; in only two places ap- 

 pear viridite and "yellowish green translucent needles of pistazite. 

 The rock of the ' Needle' can therefore be regarded as unusually fresh 

 and 'healthy,' in spite of the honorable age which it possesses." 



The specimen, on which these examinations were made, probably 

 formed part of the material cut off, in 1880, from portions of the 

 base of the shaft, by direction of Commander Gorringe, in order to 

 increase its bearing surface on the pedestal and stability, and to 

 facilitate the attachment of the new bronze crabs. About four 

 barrels full of pieces were at that time removed, and are now pre- 

 served in the American Museum of Natural History. 



Within about a couple of years afterward, the incipient decay of 

 the surface seems to have been first indicated by small pieces of 

 granite, lying around the base, evidently fallen from above. This 

 sudden and strange disintegration was met at first with great in- 

 credulity, since it was plainly not due to old age ; the monolith had 

 yet seven centuries to catch up with the age of its sturdy old com- 

 panion, still on the site of An. 



In October, 1883, this change was brought to the attention of 

 Dr. F. A. P. Barnard,^ who found "the surface of the stone step, 

 immediately below the plinth, sparsely strewn with minute frag- 

 ments of the rock," carefully swept them off, collected and weighed 

 them, to the amount of 24.56 grams (about | of an ounce). From 

 this he calculated the waste per square meter of the surface of the 



1 Frazer, loc. cit., 3(54; Gorringe, op. cit., 161. 



2 Frazer, loc. cit., 372-374; Gorringe, op. cit., 166-167. 

 8 Evening Post, New York, Oct. 30, 1883. 



