1919 J SOILS FERTILIZERS. 121 



No. 2.— Trans-Atlantic Flight from the Meteorologist's Point of View (illus.), 

 by W. R. Gregg; The Flight of Aircraft and the Deflective Influence of the 

 Earth's Rotation (illus.) . by C. F. Marvin; United States Still Holds Aii-plane 

 Altitude Record (reprinted) ; Air Routes to Australia (illus.), by G. Taylor; 

 Report of the British Civil Aerial Transport Committee, by W. R. Gregg (rev.) ; 

 Meteorologj' During and After the War, by H. G. Lyons (extracts) ; Meteoro- 

 logical Service of the Army, by G. O. Squier (reprinted) ; [Bibliography of 

 papers by R. DeC. Ward, on Influence of Weather on Military Operations], by 

 M. Welch; Measurements of the Solar Constant of Radiation, by C. G. Abbot; 

 The Direction of Rotation of Cyclonic Depressions (illus.), by J. S. Dines; 

 Additional Note on Clockwise and Counterclockwise Cyclonic Motions with Ap- 

 plication to the Flight of Aircraft, by C. F. Marvin ; Weather Maps in London 

 Newspapers (rev.) ; Congress of Scandinavian Geophysicists in Gothenburg, 

 August 28-31, 1918. by H. Pettersson ; Weather Forecasting (illus.), by V. 

 Bjerknes; On the Structure of Moving Cyclones (illus.), by J. Bjerknes; Pos- 

 sible Improvements in Weather Forecasting, by V. Bjerknes ; Synoptic Study of 

 Hydrographical Phenomena (illus.), by H. Petters.son; Notes on the Fluctua- 

 tions of Mean Sea Level in Relation to Variations in Barometric Pressure, by 

 T. B. Franklin (abs.) ; The Effect of Wind on Sea Level (extract) ; An Instru- 

 ment for Accurate and Rapid Density Measurements on Board Ship, by A. L. 

 Thuras (abs.) ; An Electrical Instrument for Recording Sea Water Salinity, 

 by E. E. Weibel and A. L. Thuras (abs.) ; William AUingham (reprinted) ; 

 Captain Melville Willis Campbell Hepworth (reprinted) ; Relation between 

 Vegetative and Frostless Periods (ilus.), by J. B. Kincer (see p. 118) ; and 

 Weather Control of the Periodical Cicada, by W. E. Hurd. 



Climatological data for the United States by sections (V. S. Dept. Agr., 

 Weather Bur. Climat. Data, 6 (1919), Nos. 1, pp. 211, i)ls. 4, figs. 2; 2, pp. 211, 

 l)1s. 4, figs. 2). — ^These volumes contain brief summaries and detailed tabular 

 statements of climatological data for each State for January and February, 

 1919, respectively. 



General classification of meteorological literature, C. F. Bkooks {U. S. Mo. 

 Weather Rev., 47 {1919), No. 1, pp. 42, 4-'^)- — A general classification designed to 

 furnish a logical, simple, and easily remembered system for filing notes, pam- 

 phlets, and references is given. 



SOILS— FERTILIZERS. 



Studies in the reversibility of the colloidal condition of soils, A. B. Beau- 

 mont (Ncto York Cornell Sta. Mem. 21 (1919). pp. 479^-524). — Investigations 

 with artificially prepared colloids, including colloidal silica, alumina, and 

 ferric oxids, and humus, together with Dunkirk and Clyde surface soils and 

 Dunkirk and Vergennes subsoils are described in an effort " to throw some 

 light on the physical changes, and their effects, which a soil undergoes with 

 variations in its moisture content, especially on being wetted and dried. 

 ... It has resolved itself into a study of the reversibility of the colloidal 

 condition of .soils." The reversibility of the colloidal state of soils is believed 

 to include " all cases brought about by physical, chemical, and biological 

 agencies or a combination of these," and is represented as follows: 



fSol 

 Noncolloidal 8tate;=±Collodial state | Tl 



I Gel 



Evidence bearing on the occurrence of various colloidal materials in the 

 soil is presented, and investigations dealing with the effect of moisture changes 



