THE EXTRACTION OF THE JUICE BY MILLS 193 



law, and under exactly the same condition as in that computation, require 



9-5 X 0-20-5 =_L_f o-6o-*— 0-20-M =1467 



inch-lbs., or 87 H.P., as compared with the 35 H.P. found before. 



Similarly, if the relation H^P =9-5 hold to so high a limit, the ultimate 



pressure on the layer of bagasse will be P = 



9-5 



0-2^ 



29,687 lbs. per sq. in., 



whereas when H = 0-25, P is only 10,000 lbs. per sq. in. 



Under the very high pressures it was found that each diminution in the 

 volume of the bagasse was accompanied by an equal volume of juice expressed. 

 Consider a column of bagasse on a base of i sq. in. and 0-25 inch high, and 

 let this quantity of material contain 0-00855 lb. fibre and 0-00855 lb. juice, 

 i.e., 50 per cent, fibre and 50 per cent, juice. Let the column of bagasse 

 be compressed to a height of 0-20 inch, then it will contain 0-00855 lb. fibre 

 and 0-00670 lb. juice, taking the 0-05 cu. in. of juice expressed as weighing 

 0-037 ^^- That is to saj^ the bagasse will now contain 56-0 per cent, fibre 

 and 44-0 per cent, juice. 



On this argument the following table may be constructed, referred to 

 the same basis as before, namely 100,000 lbs. of cane, with 12 per cent, fibre 

 per hour, in a 78-inch mill describing 23,400 sq. in. in one minute. 



An idea of the variation in the composition of the bagasse ^\dth variation 

 in the quantity of cane milled, the power remaining the same, may be obtained 

 as under. In the preceding section it was estimated that 590 - 1 inch-pounds 

 were required to compress a column of bagasse i sq. in. section and o-6 

 inch high to a height of o - 25 inch, and on compression the bagasse was taken 

 as containing 50 per cent, fibre and 50 per cent, juice. Let twice the quantity 

 of bagasse be compressed, the original height being i - 2 inches ; let x be the 

 height to which this quantity of bagasse can be compressed by 590 - 1 inch- 

 pounds : then 2^ X 9 - 5 H'^ = 590 • i 



whence x= 0-602. 



This height of the column of bagasse corresponds to a height of 0-301 

 inch, when the quarttity of cane milled is 100,000 lbs. per hour, and when 

 in this case the column of bagasse was o- 25 inch high it contained 50 per cent, 

 fibre, there being 0-00855 lb. fibre and 0-00855 lb. juice. With a height 



p 



