THE COMPOSITION OF QUICKSAND 355 



underneath a bed of sand. Mr. C. Cams -Wilson 

 has shown that there are also quicksands in which 

 there is no upward or other current. They are 

 produced by the inclusion of gas in wet sand. 

 Such quicksands are found in Morecambe Bay 

 where cockles and other organisms are present in 

 numbers sufficient to produce during decomposi- 

 tion large quantities of gas. 



In a lecture upon some properties of sand 

 delivered at the Royal Institution Mr. C. E. S. 

 Phillips illustrated the effect of included gas in 

 quickening sand. He had two beakers con- 

 taining sand, to one of which water only had been 

 added, to the other a little carbonate and hydro- 

 chloric acid also. When the point of the finger 

 was pressed upon the surface of the sand which 

 contained water but no gas it penetrated only a 

 short distance, after which the material offered solid 

 resistance. When the point of the finger was 

 pressed upon the surface of the wet sand in the 

 other beaker (in which carbonic acid had been 

 generated, some of which was still enclosed in the 

 wet sand) there was no stiffening of the material, 

 and the finger could be pressed down without 

 increase of resistance. 



There are three kinds of fluid— viz., gaseous, 

 liquid, and granular— and such a statical quicksand 



