426 FIRE-CONSERVANCY. 



ing block, so that 'this fire may spread towards and meet the ad- 

 vancing conflagration. The lighting of such a fire is technically 

 turned counterfiring and its object is to prevent the larger confla- 

 gration, in view of its intense heat, from attaining a too dangerous 

 proximity to the intact block. The subject of counterfiring will be 

 dealt with iu more detail in a subsequent section. 



ARTICLE. 3. 



FIRE-TKACING. 



Expressed briefly and in the most general terms, a fire-trace i& 

 cleared by cutting and sweeping away all inflammable matter from 

 over a certain width along both of its edges, and then firing all the 

 intervening grass and other combustible stuff, the burning being, 

 regulated and controlled by a gang of men stationed along each 

 edge and provided with bunches of stout leafy twigs, with which 

 the spreading flames can, when necessary, be beaten out. The two 

 cleared lines, one along each edge of the fire-trace, which serve 

 both as an alignment to the men and to prevent the fire from get- 

 ting beyond the trace into the forest to be preserved, may appro- 

 priately be termed guide or check lines. 



In fire-tracing operations it is necessary to know (1) in what 

 direction to run the traces, (2) what width to give them, and (3) 

 how to prepare them. 



I. Direction for afire-trace. 



The direction in which a fire-trace should run is generally fixed 

 for it by existing natural features or roads or the boundary it has 

 to follow. But sometimes, as when there are no lines on the ground 

 to determine its direction or the choice lies between two or more 

 such lines, then full consideration, within the measure of discretion 

 allowed by other circumstances, should be given to the quarter from 

 which a constant wind blows. If the trace ran at right angles to- 

 the line of such a wind, its firing would become extremely difficult, 

 if not practically impossible, for it must be remembered that the 

 force of the wind would become more than doubled by the burning 

 of the grass on the trace, and the violence of the fire and the 

 length of the flames to leeward of the trace would consequently 

 necessitate a very broad guide-line, the cost of which might be 

 entirely prohibitive. In close-standing fairly dry grass only four- 

 feet high the flames may, when only a stiffish breeze is blowing, 

 reach across a guide-line 16 feet wide and set on fire the grass 

 beyond. 



