DETERMINING GREASE AND DIRT IN WOOL. 15 



Table 6 shows that the grease removed from the 60 Rambouillet 

 fleece samples by the first three extractions averaged 16.66 per cent 

 of the conditioned weight of the raw wool, while at the fourth extrac- 

 tion the per cent averaged 16.83, or 0.17 per cent removed by the 

 fom'th treatment. From the 60 crossbred samples an average of 

 12.77 per cent of grease was removed by the first three treatments, 

 and 13.05 per cent by four, or 0.28 per cent by the fourth treatment. 

 From the extremely small amount of grease removed by the fourth 

 extraction in each case, it is assumed that the per cent of grease 

 extracted by the four treatments shows the total quantity of grease 

 contained in the samples, and that the per cent removed by the 

 fourth is negligible. Using the figures obtained from the four extrac- 

 tions as the total amount of grease, and therefore as a basis for 

 calculation. Table 6 shows that 98.99 per cent of the total grease was 

 removed by three extractions from the Rambouillet samples and 

 97.84 per cent from the crossbred. Since these tests show that only 

 a negligible quantity of grease is removed by the fourth extraction, 

 it has been decided to use three gasoline treatments in the scouring 

 process. 



DETERMINING WEIGHT OF DIRT. 



Before the third conditioning of the wool in the oven, it is necessary 

 to remove all the dirt in order to obtain the clean-wool weight. A 

 part of the dirt is of course removed with the grease by the gasoline 

 treatments. This is caught by the filter papers and kept with the 

 samples until they are ready to be washed in the tub, when the dirty 

 filter papers are thrown away. The rest of the dirt is removed by 

 means of soap and water in the tub, about half a pound of neutral 

 soap proving to be sufficient for the 150 gallons of water used. The 

 temperature of the water is kept at 40° to 45° C, as trials showed that 

 temperature to be sufficient for the removal of the dirt, without being 

 hot enough to felt the wool. After the wool has been washed, rinsed, 

 and dried in blower and oven, the clean weight of the wool is taken. 

 The weight of dirt is determined by subtracting the weight of 

 clean wool from the weight of degreased wool before the removal of 

 the dirt. 



WEEKLY WORKING SCHEDULE. 



In order to scour all the samples sent to the laboratory each year, 

 it is necessary to complete 60 each week. Owing to the fact that in 

 the process each set of samples must dry after the various treat- 

 ments — three hours in the conditioning oven at three different times, 

 about three hours between each of the three gasoline treatments, and 

 eight hours in the blower dryer — it is evident that considerable time 

 elapses between the beginning and the completion of the scouring of 

 each run of samples. For example, a run started on Monday will be 

 completed on Friday, 



