52 



TRANSPORTATION ON LAND BY VEHICLES: -THE ROADS 



is SO loose that it cannot withstand the pressure of a wheel. Two things can be done to strengthen 

 a dirt road:- 



(a) The top surface can be formed by that mixture of clay and sand which combines the good 

 qualities of the two materials most efficiently ("sand-clay-roads"); 



(b) The top surface can be so crowned or so tilted toward the valley that the water falling on it 

 is forced sideways, the surface acting as a roof. 



In spite of all, nevertheless, a dirt road is never fit for heavy traffic in wet weather. 



II. Ice cover. 



(a) North of Mason and Dixon'S line the winter months offer, for a certainty, frozen ground 

 frequently covered for a number of weeks by a layer of snow. 



By this means is made possible the use of sleds in logging. The frictional resistance which sleds 

 meet on "iced roads" is small, amounting to 3 per cent of the load appro.ximately. 



This means to say that sleds on a 3 per cent downhill grade do not require any tractive force, the 

 frictional resistance being overcome by the gravity pull. 



In the South, snow and ice are, owing to the irregularity of their ocurrence, an impediment to the 

 transportation of logs in the woods. In the North, the logging operations are frequently concentrated on 

 the winter months. Then it is that the soil is in an excellent condition of firmness. 



(b) Ice roads. The ice roads are laid 

 out in the summer and fall preceding the win- 

 ter's campaign. The roads should follow the 

 depressions, so that the skidding to the roads 

 can be effected from two sides. The swamps 

 of the valleys, or glacial lakes left in the North 

 woods, offer excellent routing for the roads. 



Uphill grades should be avoided. Down- 

 hill grades exceeding 15 per cent endanger 

 the horses. On steep grades it is necessary 

 to increase the frictional resistance and to 

 sprinkle the ice with sand, hay, small twigs, 

 and the like. 



Heavy frictional resistance, however, cau- 

 ses the sled runners to wear rapidly. It is 

 also responsible for the stalling of teams, with 

 the resuh that all the teams in the rear of the 

 team stalled are badly delayed. 



According to the chances which the oper- 

 ator takes with reference fo the layer of snow, 

 the stumps on the route are removed entirely or are left at a height of l''_. feet. 



(c) Operation. To begin with, the snow is plowed away by a snow plow where it has accumulated 

 unduly. The plow is followed by a "tracking sled" lightly loaded and meant to impress on the snow the 

 ruts of the sled runners. The tracking sled in turn is followed by the "sprinkling sled," usually run at 

 night, which sprinkles water in the ruts, so as to cause the formation in them of a strong ice crust. 



III. Woodcover. 



(a) Wood covered roads are found in the form of sawdust roads (Southern States) and of plank 

 roads (swamps). The planks are placed directly on the ground, square across the road bed. Sometimes, 

 on the Gulf Coast, plank roads consist of long and low trestle bridges. 



(b) Corduroy roads are especially met where there is swampy or moist soil, or deep humus on 

 the ground floor. Corduroying costs, at BiUmore, according to width of road and distance of transportation 

 of split chestnut wood, from ^^4 to j^ 10 per hundred feet of length. In the balsam swamps of the Adirondacks, 



The result of a winter's logging on the ice of an Adirondack lake. 



