RETTING 123 



intelligence. The workman has simply to proceed mechanically 

 and carefully in accordance with the instructions. 



The requisite supply of oxygen to sustain the aerobic bacilli 

 is commenced and continued from this stage. The operation 

 is achieved by running along the bottom of each side of the vat 

 a small perforated pipe through which air is continuously 

 forced by an air compressor, capable of supplying 200 litres 

 of air per minute simultaneously to each vat in the series of 

 four. Each vat requires 4 litres of air per cubic metre per 

 minute. The continuous current of air rises and passes 

 through the volume of water until it reaches the surface, where 

 it agitates the water to such an extent as to produce a boiling 

 effect and an abundance of white foam. The foam rises as 

 much as a metre in height and freely overflows from vat to vat. 



The retting operation is completed in thirty-six to forty 

 hours, after which the water is run off directly into the river, 

 and since it retains its free oxygen no harm is consequently 

 done to the fish. 



The flax is then removed and put into cars, or trucks, which 

 run alongside the vats and the door of the retting room, from 

 which the flax is taken into a drying room to be artificially 

 dried in the winter, but in fine summer weather it is taken on 

 to the grass to be naturally dried. 



The artificial drying room is 26 metres (28 yds.) long and 

 open at each end. Through it hot air blasts are continuously 

 forced, and a pair of winged radiating pipes are laid along the 

 floor. About two hours are required to complete the drying. 

 The results achieved by this method are claimed to be equal 

 in quality of fibre and better in yield of scutched flax. 



DRYING AFTER RETTING 



Whatever method of retting may have been adopted it is 

 necessary to dry the flax and preferably in the open air. Two 

 methods are common : (1) Spreading ; (2) Gaiting. 



104. Spreading. Clean lea, or newly-cut grass, is the best 

 place to spread flax. The flax should be well and evenly 



