Current Literature. 



249 



tween snow and the ground, or prevent the breaking loose of 

 snow. It is then extremely important to know the starting point. 

 Local reports are not always reliable, neither can one make 

 positive conclusion from the starting of one avalanche, as the 

 conditions of the origin of the avalanches, such as other kinds 

 of winds, different snow, new burns, etc., may vary the condi- 

 tions. If the starting point should be difficult to locate it is 

 always safe to build rather too high than too low so that in case 

 the avalanches should re-occur the work would not be swept 

 away. The starting point of an avalanche on slopes is very 

 frequently found on the change of grade, and to such points 

 attention should be specially directed, also on places where over- 

 hanging snowdrifts are amassed, and these cases should be care- 

 fully observed. 



The constructions vary with the topography and local material 

 at hand, and consist mostly of posts, wood or iron, high stone 

 walls, terraces and banquettes, snow catchers and ditches. If 

 these constructions are within the timber line (timber line is 

 here understood not the present line but the line which can be 

 reached by artificial planting), the main purpose is to establish 

 a forest between these constructions in order to make the pro- 

 tection as permanent as possible. This has been the general 

 practice in most of the constructions of the past to establish a 

 forest. 



The second group, which treats of constructions to deflect 

 avalanches, consists mostly of high stone walls in order to direct 

 the snow into places where less or no damage can be done. 



Under the revised federal law of Switzerland expropriations 

 for the creation of new ban forests can be made. The most 

 extensive works of this kind are conducted by railroads. 



Up to the present out of 268 larger constructions in Switzer- 

 land, 200 are completed at a total cost of two million francs, 

 54% of this being paid by the federal Swiss government. 



What is done in the Alps is, however, with us entirely out 

 of the question from practical points of view. The value of the 

 property endangered would not warrant any great expense in 

 protecting it, and the territory over which construction v/ork 

 would have to be done in order to protect even one valley is large. 



