, 1889-07-20

tAOSO1 OOuALS1 OOHSC - "a O0A
experiments on the lines OF those of the
previous years and to remain dependent
for the completion of them upon the kind
ness Of neighbOuring planters.
The present method Of carrying out the
.s eGpenmentSs
The canes ON the plots are topped
and cut in the usual way, the tops on
each plot being counted and weighed, the
canes are carted to the mill yard, weighed
and passed through the mill, the juice is
received iuto a clarifer and gagged, it's
temperature at time of measurement being
noted. A sample OF the juice is taken, 30
cubic centimetres at 81 o/oFah. is measur-
ed into a one hundred cubic centime.
tire flask, treated with lead subacetate,
alumina cream and a small excess
Of sodium bi-sulphite made up to the
mark, filtered ard the sucrose determin-
ed in it by polarization, the instru-
ment used being a very fine one by Lau-
cent using ordinary light, sensitive to $500
with 200 MIN. tubes to O2o(o with those OF
500 o.. which was presented to one OF US
for use in these experiments, by Edward
Easton, C.E., FIGS the Glucose is, at the
same time, determined in it by Paws
modification of Fehling's test. For these
experiments, the PAWS solution is previ-
ouSly standardized on freshly expressed
cane Juice, the glucose in which has been
accurately determined by SOxhlets method.
Used in this manner in our experience OF
some years, Pavy's modification is not only
by far the most convenient for our work,
but leaves nothing to be desired either in
accuracy, ease of manipulation, or des-
patch. These two determinations are, as
a rule, completed in less than half al
hour, from the crushing of the canes.
Some of the sample Of juice is placed III n
bottle of known capacity containing a
weighed amount Of dry saIycilic acid,
which prevents fermentation and preserves
it without change for some time. In this
portion at the laboratory, the specific
gravity is determined by the specific gra-
witty bottle the total solids by evapOrating
in large platinum basins a weighed guam.
tity 1.-TWO to three grammeS) to dryness
upon the water bath, and drying i'll the
water'oven until of constant weight the
ash is determined by evaporating a larger
quantity to dryness and incinerating in
a mufae at q barely visible red heat, and
the nitrogen by K%jeldahPs method,
using 90 to 81 grammes of the juice.
From the Volume of expressed juice, the
temperature of measurement, and the Spe-
cidc gravity, the weight of juice obtained
by the mill is calculated. During the
crushing of the canes samples of the
megass are constantly taken as it leaves
the rollers, at once placed in light bags,
weighed and sewed up; the bags are
then placed where they attain a tempera-
ture Of from 14O deg. to $50 deg. Fair.
and remain there until they have lost from
40 TO $500 of their weight, the megass
then containing from eight to ten per cent
of moisture. In this state the megass may
be kept for a length of time without altera-
ton. The bags are weighed before analy-
sis, the contents cut up into pieces OF
from ] to 2 inch mixed together, portions
sampled out, which are cut up more finely
and ground to a coarse powder. In this,
the moisture and ash are determined in the
usual way ; 1852 grammes extracted in the
modified Soxhlet apparatus already NELL
toned, the extract clarified in the same
way as the juice, made up to 200 cubic
centimetres, filtered and the readings taken
in either IA sodium light or an ordinary
light Laurent instrument using the 400 nm.
tubes, the result thus obtained being
occasionally checked by extracting 26.O4S
grammes and using a Soliel Scheibler
instrument. The glucose is determined
by either PAWS or Soxhlet's method, COR
~rectiOns are made for the influence of the
inverted sugar upon the pOlariscope read
ings, and the proportions of the sugars
found are calculated into the ratio in which
they were found to be in the juice. The
Al>.o 20 Iatorunino1 hv froofinu SomOlnS in