210 EXPERIMENT STATION RECORD. [Vol.38 



Baker (see p. 209) ; Dark Day in Jamaica; and Distance at Which Thunder 

 Can Be Heard, by C. E. Miller. 



No. 8.— Aurora of August 21, 1917, by D. F. Manning ; Aurora of August 25, 

 1917, at Washington, D. C, by I. P. Hand and C. Abbe, jr. ; Parhelia 90° from 

 the Sun Seen in Jamaica (illus.), by M. Hall (reprinted) ; Magnetic Storm of 

 August 2G-27, 191C, by W. E. W. Jackson (reprinted abs.) ; Comparison of 

 Callendar Sunshine Recorder and Angstrom Pyrheliometer, by J. Patterson 

 (reprinted abs.) ; Penetrating Radiiation in the Atmo.sphere, by G. G. Simpson 

 (reprinted abs.) ; Meteorology and Aviation, by W. H. Dines (abs.) ; Predicting 

 Minimum Temperatures (with a historical note by C. F. Marvin), by J. W. 

 Smith (see p. 209) ; The Lowest Air Temperature at a Meteorological Sta- 

 tion, by B. Galitzin (Golitsyn) ; Notes on the Hot Wave in Southern California, 

 June 14-17, 1917 (illus.), by F. A. Carpenter; Changes in Weather Bureau 

 Program of Meteorological Observations, by A. J. Henry (abs.) ; The Weather 

 Bureau and the War, by B. B. Calvert (abs.) ; Normal Anomalies of Mean 

 Annual Temperature Variations, by H. Arctowski (reprinted abs.) (E. S. R., 

 37, p. 417) ; Structure of Hailstones of Exceptional Form and Size, by F. E. 

 Lloyd (reprinted abs.) ; Improved Methods in Hygrometry, by A. N. Shaw 

 (reprinted abs.) (E. S. R., 37, p. 16) ; Factors Influencing the Condensation of 

 Aqueous Vapor in the Atmospliere, by A. Masini (repi'inted abs.) (E. S. R., 

 37, p. 716) ; Evaporation of Mercury Droplets Suspended in a Gas, by A. 

 Schidlof and A. Karpowicz (reprinted abs.) ; Evaporation and Absorption, by 

 A. Schidlof (reprinted abs.) ; Dynamics of Revolving Fluids, by Lord Ray- 

 leigh (reprinted abs.) ; and A Quintette of Cold Waves in Florida (illus.), 

 by A. J. Mitchell. 



Meteorolog'ical observations at the Massachusetts Agricultural Experiment 

 Station, J. E. Osteandeb and H. B. Millaed (MassacJiusetts Sta. Met. Bills. 

 345-34G (1911), pp. 4 each). — Summaries of observations at Amherst, Mass., on 

 pressure, temperature, humidity, precipitation, wind, sunshine, cloudiness, and 

 casual phenomena during September and October, 1917, are presented. The 

 data are briefly discussed in general notes on the weather of each month. 



SOILS— FEETILIZEES. 



Some notes on the direct determination of the hygroscopic coefficient, P. J. 

 Alway, M. a. Kline, and G. R. McDole (U. S. Dept. Agr., Jour. Agr. Research, 

 11 {1911), No. 4, pp. I4I-I66). — This reports investigations conducted at the 

 Nebraska Experiment Station from 1910 to 1913, on the development of a 

 method for the direct determination of the hygroscopic coefficient in soils, 

 earlier studies (E. S. R., 20, p. 714) having led to such modifications of Hil- 

 gard's method (E. S. R., 15, p. 746) as would periuit a large number of deter- 

 minations being made rapidly without loss of accuracy. Observations were 

 made upon the influence of the material of the trays, time of exposure, tem- 

 perature, grinding, and various other factors. Tabulated data are presented 

 and discussed for each point studied. 



The conclusions reached were that " the amount of hygroscopic moisture ab- 

 sorbed increases with the rise of temperature. Drying of mineral soils at 

 temperatures of 100 to 110° C. does not appreciably decrease their hygroscop- 

 icity. Intractable samples may be reduced in a steel mortar to pass a 1-mm. 

 sieve without appreciably affecting their hygroseopicity. Twelve hours' ex- 

 posure in the absorption boxes is sufficient only when the soil layer is very 

 .shallow. In practice a longer interval is found more convenient, 20 to 24 hours 

 proving very satisfactory. An exposure of more than 24 hours gives higher 

 values in the case of only very fine textured soils. 



