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'  . 268  \ REPORT OF THE COMMISSIONER OF AGRICULTURE. 
BROWN COAL AND WOOD CHAR IN THE FILTRATION 
OF CANE JUICES AND SIRUPS. 
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Report of W. J. THOMPSON. 3 
\ & 
CALUMET SuGAR-HoussE, Bayou TECHE, LA., — 7 
Wednesday, February 29, 1888. : 
DEAR Sir: Pursuant to the conditions attaching 9 tons of German 
lignite furnished him by the U. 8. Department of Agriculture for 
experimentation in cane-juice filtration at this factory, Iam instructed 
by Mr. Daniel Thompson, its proprietor, under whose exclusive 
patronage the experiments have otherwise been conducted, to make 
you the folowing report concerning the same: 
A miniature apparatus, comprising mill, steam defecators, open 
steam evaporators, subsiders, and a laboratory frame filter-press 
from Wegelin and Hiibner, center-feed, executed in bronze, of one- 
half square foot filtering area, arranged for complete displacement, 
offered reasonable facilities at all times to small work. Four Kroog 
presses of thirty frames, 220 square feet filtering surface each, so 
mounted with respect to receiving vessels, juice, and lixiviating 
pumps, safety-valves, and lke appurtenances as to have operated 
upon scums throughout the season without suggesting alteration, 
besides eliciting the eulogiums of the inventor of the so-called Brown 
coal process, served during industrial trials. All pipes were of cop- — 
per or brass, pumps of bronze, and the plates, perforated sheets, 
frames, and other iron parts of the apparatus in contact with juice 
all thoroughly painted, as insurance against discoloration of prod- 
ucts. A well-arranged chemical laboratory, unusually wellequipped ~— 
for investigations connected with sugar, was also provided. : 
Mr. B. Remmers, an English expert in mechanical filtration and 
sugar refining, well known to readers of the Sugar Cane Magazine, 
_ assumed technical control of the experiments, assisted by Mr. R. A. 
Willams, chemist from the Louisiana Sugar Experiment Station, 
Mr. J. P. Baldwin, a local adept in defecation, and two long-time 
employés of the factory. 
A preliminary study was made of cake formation. For this pur- 
pose Spanish whiting, variously colored, as with aniline dyes and 
alizarine, kept mechanically suspended in water by vigorous agita- 
tion, was pumped into the chambers, the cakes being finished off at . 
high pressures to insure extreme solidity, which, after removal, were 
cut into sections, longitudinal and transverse. It was found that, 
with constant or very gradually increased pressures maintained 
within the chambers, and a liquid kept under unaltered conditions, 
the cakes formed by extremely uniform accretions, beginning with 
a thin and even coating of the entire filtering area, over which the 
various colors used deposited one upon the other, as fed in succes- 
sion to the press, in likewise thin onal equable layers, until the cham- 
bers were quite filled and filtration ceased. With oscillatory press- 
ures and with substances of widely differing specific gravities, such 
as whiting, brown coal, red lead, wood char, and ultramarine, one 
following upon the other, the various laminz proved most irregular 
in their deposition upon the filter-bed, being comparatively of excess- 
ive thickness in parts while running out altogether in others, the 
plane of contact being besides often obliterated or scarcely defined, 
because of partial intermingling between the different substances 
LH 
