230 Reviews — E. A. Neivell Arber—On Coal. 



4. Water Supply of the United States. — We Lave received a 

 number of Water Supply Papers published by the United States 

 Geological Survey. No. 255, "Underground Waters for Farm Use," 

 by Mr. M. L. Fuller, is a general treatise on water supply and sanitary 

 matters, including methods of sinking and boring, cost, etc. It is 

 well illustrated. No. 254, "The Underground Waters of North- 

 Central Indiana," is by Mr. S. It. Capps, with a chapter on the 

 chemical characters of the waters by Mr. II. 13. Dole. A full account 

 is given of the geography, the geological formations and structure 

 of the region, of the ground waters, artesian areas, and the supplies 

 of water to various localities and for various purposes. No. 240, 

 " Geology and Water Resources of the San Luis Valley, Colorado," 

 by Mr. 0. E. Siebenthal, deals with the geography and geology, the 

 climate, agriculture, the alkali soils and the methods of irrigation, 

 the springs, underground waters, flowing and non-flowing wells. 

 Most of these subjects are also dealt with in No. 221, "Geology and 

 Water Resources of the Great Falls Region, Montana," by Mr. C. A. 

 Fisher. Other papers treat of the surface-water supply and the water 

 powers of various regions in the United States. 



5. Desert Water Supplies. — In the Cairo Scientific Journal 

 (vol. iv, July, 1910) Mr. G. W. Grabham has questioned some of the 

 explanations given by Mr. H. J. L. Beadnell with respect to the 

 flowing wells in the Nubian Sandstone of Kharga Oasis (see Geol. 

 Mag., 1908 and 1909), and suggests "that the constituents of sand- 

 stone, though incompressible, are slightly elastic, and when a bore is 

 opened the ground in its neighbourhood may actually subside owing 

 to the reduction of hydrostatic pressure beneath. This subsidence 

 would react on the yield of the well in two ways, namely, expression 

 of the accumulation of water and reduction in size of the sandstone 

 pores, which, though very slight, would tend to reduce the rate of 

 flow. When a bore is closed, the static pressure in its neighbourhood 

 increases and again tends to elevate the ground ". Mr. Beadnell 

 replies in the same Journal (vol. v, January, 1911), and observes that 

 " Even admitting, for the sake of argument, that the water held in 

 the pores of a porous bed could be squeezed out by the pressure of the 

 overlying rocks, we are faced by the difficulty of explaining how the 

 water ever obtained access to the beds in the face of such pressure, 

 which surely would have obliterated all such pores ; or, again, how 

 the water having been once expelled, could ever again be replaced". 

 He mentions that the porosity of the Nubian Sandstone " varies both 

 horizontally and vertically to a considerable degree ", and that well- 

 known facts connected with the fluctuation and depletion of artesian 

 waters do not support Mr. Grabham' s contention. 



III. — The Natural History of Coal. By E. A. Newell Aebek. 



pp. x, 163, with 21 text-illustrations. Cambridge: at the 



University Press, 1911. Price Is. net. 

 rMHIS little handbook gives in clear and concise language a statement 

 X of the leading facts and theories concerning the various forms of 

 coal and their origin, and commendable judgment is shown by the 

 author in dealing with controversial matters. Space is found for 



