588 AUXILIAKY FOREST INDUSTRIES. 



During the kindling process, the shaft of the flue, 

 especially in its upper part, burns completely and leaves a 

 hollow space in the kiln. Hollows also may form in other parts 

 of the kiln owing to a defective site, to bad piling, kindling or 

 control of the burning, or to the wood being too damp. If these 

 hollows were not filled, they would cause a draught and attract 

 the fire, the normal course of the burning would be hindered 

 and the yield of charcoal reduced. Owing to the continual 

 increase in size of these hollows, the covering might at length 

 fall in and the kiln burst into flames. All hollows must there- 

 fore be filled promptly with short pieces of wood or large pieces 

 of charcoal. 



The following method of filling hollows is adopted : When- 

 ever the burners have noticed that owing to a marked collapse 

 of the covering a hollow has been formed, and have placed the 

 wood or charcoal required to fill it alongside the kiln, they 

 should test the extent of the hollow by tapping the covering 

 with a mallet. They then remove the covering over the hollow, 

 press down the contents with a piece of wood and fill the hollow, 

 covering it again rapidly with branches and paste, and beat 

 the covering into a firm condition. All vent-holes should be 

 stopped at least one hour before filling a hollow and for a 

 whole day afterwards burning should be conducted without 

 any holes in the kiln. The hollow made by the combustion of 

 the chimney is filled on the first evening of the burning and 

 often must be filled again on the second, third, fourth and 

 even on the fifth evening. Often the top-filling is required 

 several times on the same day ; in large kilns, as many as 

 15 to 20 top- and side-fillings may be required during the 

 burning and several more whilst the kiln is cooling. 



It is evident that filling hollows in a kiln must waste charcoal, 

 as by opening the covering a draught is caused and the iiro 

 unduly stimulated ; charcoal is thus burned owing to the flames 

 lnv;i,kiiitf out, {ind in pressing down tho contc.nts of tho 

 kiln somo of tin; charcoal is bmkc.n into small pieces. 

 Filling cannot, however, bo dispensed with; every endeavour 

 should therefore be made to prevent the sides of the kiln from 

 collapsing, and to reduce a number of indispensable fillings to 

 a minimum. 



