rie iined 
~ we 
REPORT OF THE CHEMIST. 275 
49 per cent. of retained moisture on the 670 pounds of cake to be juice 
diluted to the same figures, we shouid have: 
Pounds. 
Une Te etesee. oth A aggeeiiltcn Re RALPa® & Buta AIDA EE ce orca Bea od Ae Mia a Rela eR Pee 828. 30 
MEMS NRE AUTICUR CONTERIS Oy 85 erat est Ae SS AS TLE RAN ROO NA IPRA BN 2S Lapel ers aes 28.83 
Le UNIS GUE Ee ee Ben a a eee rier Crg ict eee ae Chere Esrae rca ete 352.18 
equal to 25.5 per cent. of the cakes’ weight, which would mean the 
loss per operation of 670X0,525x0.05=17.58 pounds sucrose, or 352 
x 0.05=17.60 pounds sucrose, or to 17.60 46.1=811.36 pounds suc- 
ae day’s work of 60,000 gallons of juice, using 80 per cent. of 
ignite, 
As a matter of fact, analysis of the cake showed this to contain 2.8 
per cent. sucrose, or 18.76 pounds of the latter per pressing—a seem- 
ing paradox, dispelled by physical examination. This sufficed to 
reveal how the water, first finding its way past the cake on its line 
of contact with the iron frame, thoroughly lixiviated the extreme 
peripheral portions of this, afterwards to pass here in important vol- 
umes without effecting any good purpose, while yet having accom- 
plished only a very partial depletion of more central parts. Here 
was met the third and last serious technical objection to lignite; one 
which, since it is multiplied by the number of pressings required for 
given volumes of juice filtered, must apply to the use of any matrix 
just in proportion as larger or smaller amounts of this are essential 
to the results sought. iv 
There appeared to offer two methods of escape from this difficulty, 
each, however, involving a dilemma. Lower lixiviating pressures, 
while producing much better effects, prolonged the time required 
for the operation so far beyond the reasonable as would need double 
or treble the filter-press plant. Increased quantities of water em- 
ployed reduced the exponent, prolonged the time, and increased the 
evaporation correspondingly. A third expedient was less effective, 
but offered some collateral advantages, to wit, more perfect pulveri- 
zation of the matrix. There can be no reasonable doubt that the 
finer the state of division to which brown coal is reduced the more 
rapid becomes filtration, the more complete the decolorization effected, 
the more solid its cake, and the lower its final per cent. of retained 
juice. Sifted through the finest of millers’ silk bolting-cloth, it per- 
forms better duty in every respect than otherwise. Tt is advisedly 
stated, and with positiveness, after repeated experiment, that lignite 
can not be too finely prepared, on a large scale at least, for cane-juice 
filtration, by any mechanical means at present command, Dissolved 
even in strong alkalis and reprecipitated as an impalpable powder, 
its efficiency is yet further enhanced. 
Asa last recourse higher juice pressures, even up to 300 pounds 
per square inch on the small press, were used. This, though it 
unquestionably left remaining a cake charged likewise with less 
juice and so uniformly compact as to be better adapted to displace- 
ment, again was attended with too serious a loss of time, both in fin- 
ishing off and in subsequent lixiviation, to compensate the advantage 
in sugar redeemed or evaporation avoided. Pressures in excess of 
100 pounds per square inch are, besides, not feasible in industrial 
practice. 
A single industrial run of twenty-four hours was finally made Jan- 
uary 16 and 17 with brown coal, with intent primarily to develop 
