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_ <)> REPORT OF THE oHEMIST, = === O71 
In general, it may be safely said, the most satisfactory filtrations 
were uniformly of juices slightly acid only, 180° EF. (circa), under 
pressures which, initially low, were most gradually increased until, 
at finishing off, 60 pounds per square inch had been attained. Neither 
reasonable increase of pressure nor higher temperatures than these 
availed perceptibly. Boiling after the addition of the lignite pro- 
- duced no good result later in filtration, when intimate admixture of 
matrix and liquid had been maintained. Of displacement, or the 
depletion in sugar of the cake, more will be said hereafter. 
Utterly at variance as the coal percentages and time volumes indi- 
cated are with promises which had preceded the process to this country, 
they proved as persistent as they are disappointing. From 30 to 45 
per cent. on-the estimated crystallizable product present were shown 
over and over again to be the smallest of coal consistent with reason- 
able amounts of work done in given times, with given filtering areas, 
_ whether by the experimental or the working apparatus. Upon this 
last from one to three consecutive defecators, of exceeding 1,300 gal- 
lons each, were repeatedly essayed. Separate treatment of skimmed 
liquors and their scums did no better in the aggregate. Those sub- 
stances which peculiarly interfere with filtration appear to be remoyed 
only in minimum degree with the skimmings and sediments. Were 
_. this otherwise, separation and recovery of juice from the latter by 
filter pressing, as now practiced, would scarcely be feasible. It was 
_ the same whether witha lime, a sulphurous acid and lime, a lime and 
phosphoric acid, an acid sulphite of alumina, or an acid albumen 
defecation, under the Willcox patent, and with these re-agents in all 
proportions. Tannic acid extracted coloring matter from the brown 
coal, as did phosphoric and some other chemicals, without facilitating 
filtration. The use of lignite in alkaline solution is forbid:en by its 
solubility in such. Basic lead acetate showed no better effects with 
the small press than the rest. Carbonatation alone succeeds, and 
this, as you told me, requires no lignite. Repetition, later repeated, 
with foreign lignite prepared under Mr. Kleemanun’s individual super- 
vision and furnished by your Department, as also with native coals 
_. obtained from the Louisiana Sugar Experiment Station and other 
sources, comminuted at home, aggravated the disappointment. . All 
degrees of pulverization were tried. The amounts filtered seemed 
tolerably constant for stubble and plant-cane juices and for juices 
from freshly-cut canes, and from those many weeks windrowed. 
From old-land cane they did doubtfully better than from new; those 
deteriorated as a frost effect not altogether so well, perhaps, as those 
not so injured. Withcane freed from its adhering cerosin, by sand- 
papering prior to crushing, it went no better. Butts showed no de 
cided superiority to middles and tops. 
In all cases the filtered juices, whether from skimmed liquors or 
scums, or the two treated without previous separation, whether from 
high or low percentages of brown coal, and with whatever defecating 
agent employed, were exceedingly bright and clear from the first until - 
running haa quite ceased altogether. Another disappointment, how- 
ever, awaited inquiry into the actual improvement as to purity se- 
cured. The exponent, on the average, was raised not materially to 
exceed 1 per cent. of total solids attributable to the coal, exclusive 
. even of sweet waters. A few analyses, taken at random from the lab- 
oratory records, sufficiently illustrate this. !n every case the non-fil- 
tered and filtered samples represent, as nearly as practicable, the same - 
