Periodical Literature 151 



grade and even an up-grade is possible, if the base is laid out 

 with logs or the ribs are laid close. The best grade is 20 to 35 

 per cent,, especially in curves if the jumping of logs is to be 

 avoided. 



On very steep grades the logs can be slid only in summer and 

 dry weather, which in all respects is the best time in the high 

 mountains. Early in the morning dew and in rainy weather 

 the logs slide well even with less grade. If the grade is less 

 than 20 to 25^, winter becomes the more favorable season, 

 when the wear and tear on logs and slide is also reduced. The 

 snow turns soon into ice, when small dimensions run well, but 

 for logs it becomes necessary to roughen the ice to reduce their 

 speed. Heavy logs, especially when peeled, run most easily, 

 hence in summer they are run with dry weather, in winter with 

 wet snow. It is desirable to sort the sizes and run them separ- 

 ately. Altogether the possibility of adaptation to topgraphy 

 and other conditions in building and operating slides make them 

 a better means of transportation than wagon or sled roads, espe- 

 cially as regards changes of grades. Only as regards curves 

 special caution is needed. In no case should these have less than 

 150 to 200 feet radius, especially on steep grades, where there 

 is danger of jumping out. Here the convex side must be built 

 high and solid with booms 50 to 60 feet in length and 12 to 18 

 inch diameter, braced with rocks and otherwise. 



Special attention must be paid to drainage, which on slight 

 grades require ditches every 60 feet, on steep grades every 30 

 feet, draining underneath the outer boom. These must be kept 

 in careful repair. 



A well kept logslide — and it must be well kept especially with 

 regard to drainage — will on cool slopes last as much as 15 to 20 

 years, on south slopes not more than 4 to 6 years. The cost 

 varies so greatly according to conditions that statements have 

 meaning only with relation to described situations. A standard 

 slide cited had cost, without counting the wood, about $1.20 per 

 yard running, while in another case it had been 30 cents. The 

 cost of operation, however, is minimal. In a given case on a 

 slide, 2)^ mile long, the contract price running for all sizes over 

 10 inch, middle diameter, was not quite one cent per cubic foot, 

 (or say $1.20 per M. feet B.M., which with our labor cost would 

 have to be about double). In this case 43 men were tending the 

 slide, namely 8 to 10 at the loading, 3 at the landing, the rest as 

 watchers on the run. 



