PROTECTION AGAINST HAIL. 559 



by hail ; a record of them has been kept since 1828. The 

 chief results of the statistics there recorded may be summarised 

 as follows : — 



Communes ^Yith fields on hill-sides with south-westerly, 

 westerly and north-westerly aspects suffer most. East, south- 

 east and north-east aspects suffer much less. 



Hailstorms generally come with the S.S.W., W. and W.S.W. 

 winds. They follow the course of large river- valleys, when 

 these run N.E., but leave the valleys when they run in other 

 directions. 



No connection between systems of forest-management, nor 

 species of trees grown is discernible, either on the severity or 

 frequency of the hailstorms. 



Observations have also been made at the Meteorological Office 

 at Zurich in Switzerland, between 1883 and 1893, and in dis- 

 cussing these. Dr. C. Hess* states that hail is more frequent 

 in valleys than on mountains, where it is often transformed 

 into sleet or rain. Near marshes and lakes, hail is more 

 frequent than over woods. On passing over cultivated lands 

 or hill forests, there is a tendency to a decrease in the intensity 

 and at times an entire cessation of the hailstorms. Hailstorms 

 follow a regular line and maps could be constructed showing 

 where the crests of the hills should l)e protected by forests. 



A hailstorm most destructive to woodlands occurred on the 

 2nd of August, 1888 at Chybi, in Austrian Silesia. On 1,917 

 acres of forest, belonging to the Archduke Albrecht, three 

 confluent hailstorms almost completely destroyed 500 acres of 

 young woods and plantations, and injured 800 acres of poles, 

 middle-aged and old woods to such an extent that they had to 

 be felled. 



Mr. Rebmann, forstmeister at Strassburg, describes the 

 great damage done by a hailstorm on the 30th June, 1898, 

 which crossed Alsace from Avricourt in France, past Worth 

 to Karlsruhe into Bavaria. The storm travelled at 34 miles 

 an hour over a distance of 437 miles, lightning being almost 

 continuous. The stones were sometimes as large as the fist 

 and killed much game and birds, one man and two horses. 



* Extract from '^Nature," January .3, 189.",. Translated from " Naturwis- 

 scnschaftlich Wochcnschrift" for December 9, 1894. 



