The Pacific commercial advertiser. [volume] (Honolulu, Hawaiian Islands) 1856-1888, 1879-09-13
From the New York Grocer
The Polariscope Test.

and an a~nalyser. used for polarising light anC
analysing its properties. An instrument OF the
same name, fitted with crystals Of quartz, tC
analyse crystals of sugar, and otherwise adapted
to the analysis of cane-sugar crystals in solution
is used for determining the percentage of pure
saccharine matter in a given volume of sugar OIL
cane solution. The process is as follows, the
proportions being always necessarily the same, in
order to secure accurate results as regards the
quantity actually tested =
Weight o. cane- sugar crystals, &c ,048 grammes;
dissolve in 100 cubic centimeters of water, gent
ly heating the preparation add acetate OF lead
sufficient to precipitate filter through prepared
bone-dust to clarity reduce to the proper tenn
perature, and fill a glass tube 200 mIllimeters in
length with the solution place the tube in the
polariscope, turn on the light, look through and
adjust the instrument until both hemispheres OF
the circle, that appear In the instrument to be
divided by a dark line, present to the eye pre-
cisely the same shade of colour. The test is then
perfected the per cent. of pure sugar will be
found registered in degrees and fractions on the
scale attached to the polariscope, and may be
read through the magnifying tube. 100 degrees
represent entirely pure sugar crystals in solution.
For the purpose of levying duty on sugars the
Dutch standard for determining grade is bad
enough but the use of the polariscope will
make matters infinitely worse, and furnish q
vehicle for the safe practice of fraud indiscrimi-
nately upon the revenue, the importer, the buyer,
and the consumer, at the option OF operators
and their instigators.
So d-licate and sensitive an instrument as the
polariscope is valuable for purposes of chemical
analysis but for testing imported sugars for the
purpose of levying duty thereon. or for sale, it
would be impossible to devise any other method
whereby the Government, the importer, or the
buyer, or all together, could be defrauded with
such perfect ease and safety as through the
means afforded by the use of the polariscope :;
and against the dangerous temptation to fraud
thus offered there exists no adequate check or
hindrance.
For instance, the operator adds a few drops
more of water than the proper quantity, and the
grade is lowered or a few grammes of sugar
more than the proper quantity, and the grade is
raised. The operator may, if he prefer, slightly
adulterate high grade sugars, and thus lower
the grade for duty, and vary the practice at
pleasure. Nor is this all the colour test in the
instrument provides fresh opportunity for both
error and fraud only the most accurate eye and
skilful adjustment can exactly determine the per-
feet cOlour-blending which marks the record of
true grade upon the scale and the slightest de-
Walton theretrom raises or lowers the grade at
the pleasure of the orator. Detection is next to
impossible.
While in honest and skilful hands the volume
of cane-sugar crystals in a prepared sample can
be determined in the polariscope, a cargo or
single package of sugar will supply as many
different classifcations as there are samples used
for testing. The writer has recently spent much
time, with several prominent operators of the
polariscope in New York, IN the thorough inves-
tigatiOn OF the instrument and it's use, and in OBJ
serving the analysis of numerous samples of cane
sugar crystals, in order to know whether or not
the pOlariscope test is practicable for the purpose
of equitably levying duty upon imported sugar,
and is satisfied that it's use will facilitate and
protect revenue robbery.
The late Professor Henry highly praised the
polariscope as an instrument capable, in scienti-
fc hands, of accurately determining the percen-
tage of pure saccharine matter, contained in a
given quantity of cane-sugar crystals but Pro-
fessor Henry's opinion was predicated upon what
honest analysis could do under favourable condi-
tions, and therefore cannot properly be quoted
in unqualified support of the polariscope when
used to test cargoes of sugar for levying duty or
for purposes of trade, when such stupendous
public interests are at stake.
The delicate and secret nature of the polaris-
cope test, renders it easy and safe for the opera
tor to manipulate samples of sugar at will not
only that, take any hogshead, box, or bag of i'm
ported raw sugar, draw from the same package
two, three, or more samples, and all will test
different degrees Of sugar strength in the polaris-
cope. Take several samples from one package,
mix them together, draw any number of samples
from the mixture, and the polariscope will give
a different fractional result in each analysis.
Sometimes such variations are sufficient to change
the grade of a cargo of sugars out OF all reason,
and the operator can grade up or down at will
undetected.
The pOlariscope used to test sugars deals only
with sugar and syrup of cane crystals in solution,
and Is useless to discover the character of adult
erations IN sugar so that glucose, grape sugar,
flour, starch, barytes, muriate OF tin, sulphuric
acid, bisulphate of lime, and other substances
may abound in cane sugars and syrups analysed
in the polariscope, and not be identified The
volume only of such substances can be deter
mined by this test. Its use must therefore be
confined only to determining the amount of pure
cane sugar contained in minute samples.
| have before me the results of two sample
tests made for me under my own observation, by
a we'll known and exceedingly skIlful operator of
the polariscope in New York City. About two
ounces oil sugar were taken at random from a
package Of raw sugar, thoroughly mixed, and
from the mixture two samples were tested in the
polariscope with the following result, copied
from the register of the instrument by the opera
tor. The first sample tested recorded $50 de-
grees saccbarine matter; the second sample
tested recorded S7'S degrees OF saccharine matter.
Professor &. F. Chandler says 1.-The polarls-
cope Will complicate the collection of duty, and
open new facilities for fraud. The ordinary
testing of sugars by the polariscOpe Is not accu-
rate within one per cent In fact, differences OF
two and three per cent, or even more, may
occur when different samples are taken from the
same lot of sugar and tested by different chemists.
The result of the test by the polariscope will be
affected by various circumstances. The exposure
of the sample to the air may result in the loss or
gain of water, according to the weather, and
thus raise or lower the test. The care and skill
of the chemist, the accuracy OF his balance,
weights. measuring flask, and polariscope, tenn
perature of solution, all affect the result. 1t is
thus practically impossible to fix the value of
the sugars by the pOlariscope within one or two
per cent. The presence in the sugar of other
substances, which also influence the readings of
the polariscope, is important, substances con-
stantly present in various quantities. This plan
of classification by the pOlariscope will give the
greatest opportunities for fraud, and will, | fear,
if adopted, make it impossible for honest men to
carry on the business of refining sugar"
The conclusion is inevitable, in view of the
evidence, that, while the poplariscope might
possibly assist the Government in special cases,
like other chemical analysis, to adopt that in
strument for the purpose of levying duty on
sugars, and for selling sugars, without providing
safeguards which do not now exist, will be to
prostitute a beautiful and valuable scientific in
strument, and the science of chemistry, to base
purposes of fraud.