Periodical Literature. 503 



UTILIZATION, MARKET AND TECHNOLOGY. 



Dr. V. Almbiirg developes with great mathe- 

 Dynamics matical apparatus the dynamics which are 



of of interest in the operation of the logsHdes 



Logslides. such as are in common use in mountain 



country, especially the influence of the 

 grade on the velocity of the movement of logs ; the effect of 

 brakes to slow down the movement, in which he shows the low 

 efficiency of the so-called "wolf," a brake consisting of a sus- 

 pended log which must be lifted by the sliding log ; the influence 

 of curves and the form of the slide on the velocity ; the minimal 

 radius of such curves. 



Beitrag sur Kenntniss der dynamischen Vorgdnge bciin Abricsen des 

 Holses in Holzriesen. Centralblatt f. d. g. Forstwesen. April, 191 1, pp. 

 161-179. 



An experience of 30 years in the use of 



Wire Rope wire rope ways for the purpose of trans- 



Ways porting logs from steep mountains to val- 



in leys, has, according to Schmid, developed 



Switzerland. their usefulness, not only for temporary 



exploitation of two or three years' duration, 



but for permanent use in forest work. While the author holds 



that the ideal way is still to build roads, there are conditions 



where this is too difficult and too expensive, and here the rope 



way is in place. 



The community of Roveredo owning a 5,000 acre tract with 

 an annual cut of 70,000 cubic feet installed in 1908, one per- 

 manent rope way of about 2 miles length, with an impermanent 

 portable rope feeder of i mile in length, and several simple wire 

 ways for conveyance of cordwood. 



A road would have cost $20,000; the rope way cost $5,500 

 for the permanent and $2,400 for the movable one. The cost of 

 transportation, including amortization at 4.5% in 10 years and 

 repairs have cost $2.44 per 100 cubic feet, while on a road which 

 with 10% grade would have had to be about 6 miles long it all 

 would have been at least $354 for teaming alone. 



Another ropeway of i^ mile length, now 10 years in use, cost- 

 ing $3,600, intended to transport 35,000 cubic feet for 10 years^ 

 made the cost of transportation $2.46. 



32 



