206 FRAGMENTS OF SCIENCE 



The Sphinx of Egypt is nearly covered up by the 

 sand of the desert. The neck of the Sphinx is partly cut 

 across, not, as I am assured by Mr. Huxley, by ordinary 

 weathering, but by the eroding action of the fine sand 

 blown against it. In these cases Nature furnishes us with 

 hints which may be taken advantage of in art; and this 

 action of sand has been recently turned to extraordinary 

 account in the United States. When in Boston, I was 

 taken by my courteous and helpful friend, Mr. Josiah 

 Quincy, to see the action of the sand-blast. A kind of 

 hopper containing fine siliceous sand was connected with 

 a reservoir of compressed air, the pressure being variable 

 at pleasure. The hopper ended in a long slit, from which 

 the sand was blown. A plate of glass was placed beneath 

 this slit, and caused to pass slowly under it; it came out 

 perfectly depolished, with a bright opalescent glimmer, 

 such as could only be produced by the most careful grind- 

 ing. Every little particle of sand urged against the glass, 

 having all its energy concentrated on the point of impact, 

 formed there a little pit, the depolished surface consisting 

 of innumerable hollows of this description. 



which are those of wedges, knives, arrow-heads, etc., and all with sharp 

 cutting edges. 



"Mr. Travers explained that, notwithstanding their artificial appearance, 

 these stones were formed by the cutting action of the wind- driven sand, as it 

 passed to and fro over an exposed bowlder-bank. He gave a minute account 

 of the manner in which the varieties of form are produced, and referred to the 

 effect which the erosive action thus indicated would have on railway and other 

 works executed on sandy tracts. 



"Dr. Hector stated that although, as a group, the specimens on the table 

 could not well be mistaken for artificial productions, still the forms are so 

 peculiar, and the edges, in a few of them, so perfect, that if they were discov- 

 ered associated with human works there is no doubt that they would have been 

 referred to the so-called 'stone period.'" Extracted from the Minutes of the 

 Wellington Philosophical Society, February 9, 1869. 



