120 



The per cent of total sugar lost in bagasse here, 24.87, approaches 

 more nearly the average for Negros, as would be expected from the 

 fiber content of the cane ground. That this latter does not show such 

 a marked increase due to added trash over that previously found by 

 analysis is probably accounted for by the larger proportion of young 

 and tender canes ground in the test, tending to reduce the fiber ac- 

 tually present in the clean cane. 



Comparison of the work done by the mills in these two controls 

 emphasizes the fact that we have as yet no reliable standard for absolute 

 mill efliciency which applies when difi:erent kinds of cane are being 

 ground. There is no reason to believe that any marked variation in 

 the working of this mill took place between the first and the second 

 test, 3'et, measured by "extraction," much superior work was accom- 

 plished in the latter, 75.13 per cent of the total sucrose in the cane 

 being secured as against 69.60 per cent in the former, while, on the 

 other hand, if we apply "Watts's factor of "first mill juice per 100 parts 

 fiber of bagasse" we must believe that the better work was done in 

 the first test, since there only 168 parts mill juice were left in the 

 bagasse per 100 fiber, compared with 208 parts found in the last control. 

 These differences are far too great to be attributed to errors of analysis, 

 and the sampling was conducted in such a manner and over so long 

 a time (the final mixed sample of bagasse from Control No. 2, for 

 instance, was made up of 95 separate 200-gram samples taken at regular 

 intervals throughout the day) as to neutralize by mere numbers much 

 of the unavoidable error inherent to this part of the work. There re- 

 mains, therefore, only the qualitative difference in the fiber from these 

 tM'o kinds of cane. As a matter of fact, the variety of cane ground 

 was the same in both cases, both being of the common purple kind, 

 although that used in the first test was old, hard, and dry, while the 

 second was comparatively young and tender. Just as in the previously 

 stated results with the hand mill (see p. 95), the fiber from the soft 

 and juicy canes was found to retain a proportionately larger amount 

 of juice than that from the harder ones, although, since the total amount 

 of fiber present was less, the "extraction" was better. 



It is possible that this effect of the qualitative difference of cane fiber is 

 peculiar to single crvishing, and might tend to disappear in the ease of mills run 

 in multiple and with pressure regulators, as is indicated by the recent work of 

 Deerr,'^ Avho found on analyzing separately the bagasse of the hard rind and the 

 soft pith of the cane, as it came out from the different mills of a multiple- 

 roller train, that rind bagasse from the first mill contained more fiber and less 

 sucrose than pith bagasse; in the second mill the amount of sucrose left in pith 



'Exp. Station Hawaiian Planters' Ass. Bull. No. 30 (1909), 



