502 Scientific Intelligence. 



but having no conception, of the quaternion a/3 (cf. Gibbs), I.e. p. 

 162). 



The author is certainly mistaken in ascribing; the invention of 

 the complex operator in the theory of alternating currents to 

 Steinmetz. It was used by Heaviside as early as 1886 and 

 possibly before. 



8. The Origin of Spectra; by Paul D. Foote and F. L. 

 Mohler. Pp. 250, New York, 1922 (The Chemical Catalog 

 Company). — From the avalanche of speculations, .equations, 

 photographs, and tables of spectral lines which has been precip- 

 itated by the Bohr Theory of the atom, the authors, who are 

 research physicists at the Bureau of Standards, have attempted 

 to separate the main lines of argument and in particular to 

 present a systematic correlation of the experimental facts. The 

 present volume is the ninth to appear in the Monograph Series 

 of the American Chemical Society. 



The character of the contents may be judged from the titles 

 of the chapters, viz., The Quantum Theory of Spectroscopy, 

 Energy Diagrams, Ionization and Resonance Potentials, Atomic 

 Line Emission and Absorption Spectra, Cumulative Ionization, 

 Thermal Excitation, Thermochemical Relations, X-Ray Spectra, 

 Photoelectric Effect in Vapors, Determination of Planck's 

 Constant from Line Spectra. 



The presentation is such as to make the volume more suitable 

 as a handbook for the investigator than for a text-book. As 

 is proper to a monograph, the chapter and verse for the author- 

 ities are given for every statement of importance. Illustrations 

 of spectra and tables of data are liberally provided as are also 

 complete subject and author indexes. f. e. b. 



II. Geology and Mineralogy. 



1. Pottsville Fauna of Ohio; by Helen Morningstar. 

 Geol. Survey of Ohio, 4th ser., Bull. 25, 312 pp., 16 pis., 1 text 

 fig. (map), 1922.— The Pottsville series of Ohio has an average 

 thickness of about 255 feet, with ten marine fossiliferous zones 

 alternating with as many brackish- or fresh-water deposits, 

 three of which have fossils. Iron ores were laid down in both 

 the fresh and marine waters. Throughout the extent of the 

 exposures the author has brought together fossils from ninety- 

 three places, and these localities are fully described, along with 

 lists of the individual faunules. Then follows the description 

 of all the invertebrate forms, numbering about 200, of which 31 

 are not specifically determined. The new forms are the genus 

 Bascomella, and 20 species. As is to be expected, the bulk of 

 the fauna is made up of Bryozoa, Brachiopoda, and Mollusca. 



