90 Scientific Intelligence. 



slighted in books like this? Such omissions cannot fail to 

 foster in the minds of the student the false notion that in some 

 way experimental physics has a separate existence from theoreti- 

 cal physics. l. p. w. 



11. Elements of Electromagnetic Theory ; by S. J. Barnett, 

 New York, 1903 (The Macmillan Company).— This is a system- 

 atic treatment of the elements of electromagnetic theory with its 

 simpler non-technical applications. The English attitude of 

 making the concepts, with which one has to deal, real physical 

 entities by the use of "tubes" and mechanical ethers is empha- 

 sized. We note that the author uses the rational units of Heavi- 

 side. The large number of figures enliven the text and the 

 numerous references to original memoirs and advanced treatises 

 materially add to the value of the work for the really serious 

 student. The closing chapters on convection and displacement 

 currents, flux of electro-magnetic energy, and electric waves puts 

 the student into a position to read with profit the modern 

 theories of light and of disturbances in the ether in general. 

 The work has long been needed and is a welcome addition to our 

 literature on mathematical physics. e. b. w. 



II. Geology and Mineralogy. 



1. United States Geological Survey, CD. Walcott, Director. 

 — The following publications have recently been received : 



Folio No. 95. Columbia, Tenn. ; by C. Willard Hayes and 

 Edward O. Ulrich. The Columbia quadrangle is located on 

 the western margin of the Central Basin of Tennessee and shows 

 the topography, structure and sedimentary record of the Cincin- 

 nati arch on the western flank of which it is located. The sedi- 

 ments are Silurian and Carboniferous separated by a thin bed of 

 Chattanooga shale (Devonian). Commercially this region is of 

 great interest because of the presence of rock phosphates. Ten 

 phosphate horizons are recognized in Ordovician and Devonian 

 strata. The Ordovician phosphatic limestones were deposited in 

 very shallow water and made almost wholly from phosphatic shells 

 of mollusks, " which seem to have flourished almost to the exclasion 

 of the more characteristic elements of the Ordovician fauna." 

 The brown phosphate of commerce is the result of the leaching 

 to which these rocks have been and are now subjected. The 

 Devonian phosphate rocks are partly due to animals then living 

 but largely to the residual mantle overlying the weathered Ordo- 

 vician limestones. 



The addition of a faunal chart and of a sheet illustrating the 

 fossil fauna which appears in this folio is to be commended. 



Folio No. 96, Olivet, South Dakota; by J. E. Todd. The 

 Olivet quadrangle includes part of the James River Valley and 

 its features are those of very subdued glacial topography. With 

 the exception of a very few small outcrops of Benton and Colo- 

 rado (Cretaceous), the entire region is mantled by drift of the 



