1920] METEOROLOGY. 119 



Cniplis are also given which "sliow llic d.-itcs of last killing frost in spring 

 for eafli of the 20 years from 19()() to l'.)l!), inclusive, for [nine] selected lo- 

 calities, representing three belts, extending east and west across the country 

 over the centra! and norllicrn sections. It shows that for the belt represented. 

 by central Oklahoma, southern Tennessee, and eastern Virginia, killing frost 

 did not occur during these 20 years after the end of April. At Omaha, Nehr., 

 it occurred only twice as late as May, but did not occur after April at Cincin- 

 nati or riiiladelphia. On the other hand, at Huron and Ithaca, it occurred 

 after the close of April in all but 6, and at Wausau, Wis., in all but 2 of the 

 20 years. In each of these last three localities, it occurred once after the 

 first of .Tune during the 200-year period." 



Weather observations, H. .1. Fkanklin {Massachusetts Sta. Bui. 192 

 (1919), pp. 138-140). — Winterkilling and fro.sts in relation to cranberry culture 

 are briefly discus.sed on the basis of oi)servations during 1917 and 191S at the 

 cranberry substation at Warehani, Mass. Reference is made to tests of a new 

 method for computing niiiiimum temperatures on nights in which frost con- 

 ditions ])revail. The author is of the oiunion that "cranberry winterkilling 

 usually is due to a drying out of the vines resulting from a freezing in of the 

 roots that prohibits their taking in moisture to replace that given off by the 

 leaves exi)o.sed to strong, dry winds." 



Tliiuulerstorms (U. S. Dept. Afjr., Natl. Weather and Crop liuL. No. 18 

 {t'.KlO). p. 2, fig. 1). — A chart showing the average annual number of days with 

 thunderstorms for the different sections of the United States is given, and the 

 fre(iuency and distribution of the storms are brielly discussed 



Jlail (U. »S". Dcpt. Ayr., Natl. Weather and Crop Bui., No. 18 {1920), pp. 2, 3, 

 fiij. 1). — A chart showing the average annual number of days with hail during 

 the frostless or c)"op-growing season, based on the records of all fidl reporting 

 stations for the 20-year period 1895-1914, is given, and the distribution and 

 frequency of hailstorms are discussed. 



Monthly Weather Review (('. S. ifo. Weather Rev., 48 {1920), Nos. 1, pp. 

 6H, pis. 18, fiys. 24; 2, pp. 69-126, pis. 35, fiys. 7).— In addition to detailed sum- 

 maries of meteorological, cliniatological, and seismological data !ind weather 

 conditions for January and February, 1920, and bibliograpliical information, 

 reprints, reviews, abstracts, and minor notes, these numbers contain the follow- 

 ing contributions : 



No. 1. — Average Free-air Conditions as Observed by Means of Kites at Drexel 

 Aerological .Station, Nebr., during the Period November, 1915, to December, 1918, 

 inclusive (illus.), by W. K. CJregg (see p. 118) ; Sunshine in the United States 

 (lllus. ), by J. B. Kincer (see p. 116) ; The Sun as a Source of Power (.see p. 117) ; 

 On Observations of Solar and Sky Radiations and Their Importance to Cli- 

 matology and Biology and Also to Geophysics and Astronomy, by C. Dorno 

 (see p. 117) ; Smoke Formations in Air Drainage (illus.), by C. Hallenbeck (see 

 p. 117) ; A Cloud Cross-section of a Winter Cyclone (illus.), by C. F. Brooks; 

 Snow Crystals from the Crystallographic Standpoint (illus.), by E. T. Wherry; 

 Would a Large Reservoir Increase Rainfall V; How Rainfall Data. May Be Used 

 for Determining Road Conditions, by T. O. Shipnian (see p. 117) : and Extraordi- 

 narily High Barometer Readings in Bering Sea, January 17, 1920, by A. H. 

 Mellick. _ 



No. i?.— pjipers on Sleet and Glaze ("Ic(> Storms") ; The Nature of Sleet and 

 How it is Formed (illus.), by C. F. Brooks; A Weather Condition Which Pro- 

 duces Glaze in Northern New York, by D. F. Manning; Boundary Between a 

 South Wind and an Underrunning Northeast Wind, by C. F. Brooks ; The Pre- 

 cipitation of Sleet and the Formation of Glaze in the Eastern United States, 



I 



