138 The Philippine Journal of Science 1920 
time offsets this low purity ; but mixed grinding can be done only 
to a certain extent, as such a procedure would tend to overfill the 
boiling house with low-grade sugar products, while the crystal- 
lizer capacity would soon be exceeded. However, the amount of 
low-grade sugar produced will be the same in the end whether 
the low-purity juice comes in mixed with the better juice or 
separate. If two cane fields are being cut at the same time, the 
cane from the one showing a high-purity juice, and that from 
the other a low-purity juice, both canes will have to be accepted 
by the central, so long as the mean purity does not fall below 70 
per cent. It is not advisable to grind cane giving a 70 per cent 
purity for, say, one week and then to begin grinding cane of a 
higher purity, because the great number of lower boilings might 
keep the crystallizers and centrifugals occupied so long that the 
working of the factory would be blocked. Many modern centrals 
provide crystallizers only, but no special tanks for low-grade 
blank strikes. Under ordinary circumstances special tanks will 
not be needed, but when a large quantity of low-purity juice 
comes to a factory it will prove an advantage to have them ; for 
then good sirup will not need to be mixed with molasses from 
a poor juice which usually not only is low in purity, but also 
is hard to handle mechanically. 
The molasses from a poor juice is simply brought to string 
proof and sent to the massecuite storage tanks, each tank hold- 
ing one strike. These storage tanks are continually kept filled 
until a holiday occurs, or until the end of the grinding season; 
then they are emptied, the massecuite is spun, and the result- 
ing low-grade sugar is remelted. 
The foregoing remarks serve to lead up to the question of 
what should be done with cane of low purity. Almost invari- 
ably the planter who has his cane milled by the central on a per- 
centage basis thinks that he should derive a certain profit from 
it. I well remember one instance when cane came to the factory 
that gave a first mill juice of 38 per cent purity. This was an 
extreme case, which would undoubtedly happen but once in a 
lifetime. But when cane with a purity of from 55 to 65 per 
cent comes to, the mill day after day, with only a very small 
quantity of good cane to offset it, the question arises whether 
the central may refuse to mill such cane or whether some use 
cannot be found for it which might offset the loss that undoubt- 
edly would occur in milling it for sugar. So far as I know, 
there is at present in the Philippines no central that allows the 
