44 



BULLETIN 983, TJ. S. DEPARTMENT OF AGRICULTURE. 



SIZE OF CHIPS. 



Two cooks were made on chips of two different sizes and under 

 the conditions outlined in the table below. 



125 per cent of HoO; 2.5 per cent of H2SO4; 7.5 atmospheres; 1 5 minutes. 





Length of 

 chip with 

 the grain 

 (inches). 



Per cent 

 of total 

 sugars. 



Per cent 



Alcohol yields. 



Cook No. 



of total 

 sugars fer- 

 mentable. 



Percent 

 of dry 

 wood. 



Gallons 

 absolute 

 per ton. 



59 



JtoJ| 

 Mixture. 



20.21 



21.005 



20.14 



73.50 

 69.07 

 71.16 



7.126 

 7.214 

 7.109 



21.55 



60 



21.82 



61 



21.50 











Even the larger chips were thoroughly penetrated and cooked, and 

 the yield obtained from them compares favorably with that obtained 

 from sawdust under similar conditions. The chips, however, did not 

 extract readily, and while they were being stirred in the leaching tank 

 they were ground to a powder. In a commercial diffusion battery 

 there would not, of course, be a similar mechanical action, but the 

 time of extraction and the capacity of the battery would be decreased. 

 A lack of material prevented leaching experiments, and these results 

 were obtained primarily to determine whether material of this size 

 would give yields similar to those from sawdust. Further work 

 along this line is necessary. 



Cook No. 61 was a mixture of sawdust, small chips, and large chips 

 in the following amounts : 



Sawdust 



Large chips 

 Small chips 



Moisture. 



Per cent. 

 8.78 

 9.67 

 9.37 



Air-dry 

 weight. 



Pounds. 

 31.35 

 46.96 

 41.04 



Dry 



weight. 



Pounds. 

 28.60 

 42.41 

 37.20 



This mixture was cooked at 7.5 atmospheres with 125 per cent of 

 water and 2.5 per cent of sulphuric acid for 15 minutes. After it 

 was cooked, a sample of the mixture was taken and extracted and the 

 extract analyzed in the usual way. Another part of the sample was 

 screened through a screen having openings three-eighths of an inch 

 square, and the materials passing through the screen and remaining 

 on it were also extracted and analyzed in the usual way. The 

 following table shows the results of these analyses : 



Digested mixture. 



Moisture 

 (per cent). 



Unscreened 70. 26 



Kemaining on §-ineh screen 70. 54 



Passing through f-inch screen I 71.11 



Total 

 sugars, 



(per cent 

 of wet 



weight). 



6.616 

 6.853 

 6.688 



Total 

 solids 



(per cent 

 of wet 



weight). 



7.196 

 7.28 

 7.32 



Acidity 

 of extract 

 (C c. N/10 



NaOH). 



7.5 

 7.6 

 7.6 



