GUIDE LINKS. 429 



The first point to consider is whether guide lines can in any 

 circumstance be dispensed with. One may already exist in the 

 shape of a watercourse or road or broad well-beaten track running 

 along one edge of the trace to be cleared ; or the trace - may be 

 flanked for some distance by a belt or patch of green forest or 

 bushes which fire cannot enter. In none of these cases is there 

 any necessity for specially preparing a guide line, except in so far 

 as a little partial clearing may be required at those points here and 

 there, where these natural barriers are too narrow or covered with 

 dry grass or otherwise insufficient to stay the progress of fire. 



Occasionally in short grass and with well-trained fire-tracers, 

 when the wind is not unfavourable and the forest to be protected 

 lies only on one side of the trace, the burning may be effected with- 

 out a check-line. This has been done under the Author's supervi- 

 sion in the Central Provinces, when the entire boundary trace of a 

 forest of roughly 50 squares miles was so cleared for about Re. 1 

 per running mile, the daily wage of a man being 4 annas. 



The exceptional cases just described being left out of account, a 

 guide line must be cleared along one or both edges of a trace 

 according as the fire is to be controlled and put out along one side 

 or along both sides of it. The former is the case when the area on 

 the side on which the fire is allowed to spread unchecked is not to 

 be protected and contains no property the safety of which would 

 be thereby endangered. When only a single guide Une is employ- 

 ed, a serious risk is incurred for which it is necessary to be pre- 

 pared. If during the firing a gale should suddenly spring up and 

 carry the fire rapidly ahead of the burners, it is quite possible 

 that the conflagration may be subsequently turned back, by a 

 change in the wind, in the direction of the protected area and 

 enter it at a point where the fire-trace has not yet been cleared. 

 To provide against such a contingency the right season and time 

 of the day ought to be chosen for the fire-tracing operations. But 

 this point will be dealt with in its proper place lower down. 



The width of the guide lines in any case will of course vary with 

 the height, density and inflammability of the grass on the trace, 

 with the force and direction of the prevailing winds, and with the 

 readiness with which the area adjoining can take fire and burn. 

 Thus local knowledge and experience can alone determine in any 

 given case the minimum safe width to adopt. But subject to not 

 very important modifications imposed by local conditions, the 

 following empirical rule may be laid down : — Tlie width of guide 

 lines should be more or less equal to the height of the grass through 



