Cheam} Relative Purity of the City Waters in the United States. 265
of applying this test, as well as those already indicated,
rests on the fac that starch glucose is always added in
very large quantities for the purposes of adulteration, A
very small addition could not be satisfactorily detected.
The detection by the copper test rests on the observation
 t':at very nearly one-half of the soluble impurities in
sugar-house molasses consists of glucose in the shape of
inverted sugar. We have seen above that for a molasses
of 40° B. the soluble impurities amount to about 37% per
cent. We may, then, lay down the rule: that the percentage
 of glucose shown by the copper test cannot, in a
straight sugar-house molasses, be much greater than one.
aalf of the number expressing the density in Baumé
degrees. The reason is obvious from what has been said
of the test by the optical saccharometer.

THE CHEMICAL NEWS.

DETECTION OF STARCH SUGAR SYRUP MIXED
WITH SUGAR-HOUSE MOLASSES.*
By P. CASAMAJOR

IN previous communications I have given processes for
detecting the adulteration of cane-sugar by starch-sugar,
The adulteration of sugar-house syrups by starch glucose
is still more extensively practised than that of sugar, and a
great portion of the syrups sold by retailers in this market is
adulterated with starch glucose. This form of adulteradon
 may be very easily detected by the use of strong
methylic alcohol, in which the alcohometer of Tralles or
of Gay-Lussac will indicate about 933°.
A straight sugar-house syrup when mixed with three
times its volume of this strong methylic alcohol will dissolve
 by stirring, giving a very slight turbidity, which re.
mains suspended ; while syrups containing the usual admixture
 of starch-sugar.give a very turbid Hquid, which
separates, when left at rest, into two layers, the lower
dseing a thick viscous deposit containing the glucose
syrup.
Considerable quantities are sold of a thin syrup, of
about 32° Baumé, in which the proportion of sugar to the
.mpurities is greater than in common sugar-house molasses.
When a syrup of this kind is stirred with three times its
rolume of methylic alcohol, a marked turbidity and deposition
 will take place, which consists of pure sugar, The
crystals are hard and gritty. They adhere to the sides of
the glass, and are deposited on the bottom. There is no
resemblance between this precipitate ‘and that due to
starch-sugar syrup. : }
It may not be useless to mention that if a straight sugar.
louse syrup of about 40° B. density is stirred with three
:imes its volume of ethylic alcohol of about g3ie the syrup
will not dissolve. Hence ethylic alcohol of this strength
-s not suitable for distinguishing a syrup mixed with
starch glucose from a straight sugar-house syrup.
The presence of starch glucose in sugar-house molasses
may be easily detected by the optical saccharometer when
:he syrup has the usual density of about 40° B., and when
starch-sugar has been added in the usual quantities.
For making the test the usual weight should be taken
(16:35 grms, for Duboscq’s saccharometer, and 26-048
grms. for Ventzke’s instrument). The dire test should
show a percentage of sugar not higher than the number of
Baumé degrees indicating the density, and it may be from
2 to 3 per cent lower. To understand this, we must refer
to the composition of cane-sugar molasses of 40° B. :—
Sugar... .. .. oo. 375
Insoluble impurities .. .. 375
Water ., .. .. .. .. 25%00
If the dire@ test should indicate 55 per cent of sugar,
and if the molasses were straight, the composition would
oe—
Sugar .. «vv es ee... 355
Soluble impurities .. .. .. 20
Water... .. «. .. .. .. 25
Now a produ& of this composition would not be a clear
syrup at 40° B., but a mixture of syrup and crystals,
Therefore if the produ is a clear syrup at 400 B.,and it tests
55 per cent, it cannot be straight,
The presence of starch glucose in sugar-house molasses
may also be detected by the copper test. The possibility
“2 Paper read before the American Chemical Society, September
>. 1881.

ATOMIC ' PHYLLOTAXY
By PLINY EARLE CHASE.

GERBER (CHEMICAL NEWS, vol. xliii., p. 242-3) says that
'* no simple relation exists among his divisors, therefore
they ‘“ have no value in themselves.” There is, however,
2 relation which he failed to discover, for they are phyllo-‘atic,
 as will be seen by the following comparison :—
Gerber, Phyllotactic,
H .. o'9997 1-16 O .. 0998
D: .. o%6g Di=5-13D;, .. 0768
D; .. 1995 D,=10 .. .. 1996
D; .. 15359 D3=(x4)*0 .. 1359
Dy .. 1245 Dy=§D; .. .. 1297
These relations may have an important bearing upon
he interpretation of frost crystals and protective mimicry.
Haverford College, Pa., Nov. 10, 1881.

RELATIVE PURITY OF THE
CITY WATERS IN THE UNITED STATES,
By Dr. A. R. LEEDS.

A LEGAL suit has recently been instituted, which will
probably have a very important bearing in the future
spon the quality of the water supplied to many of the
principal cities in the United States, To understand
more readily the nature of the questions raised in this
suit, a few words of previous explanation will be requisite,
The three cities of Newark, Jersey City, and Hoboken,
with an aggregate population of 300,000 inhabitants, all
{raw their water supply from the river Passaic. Thisisa
.arge stream, having a daily flow at Newark of about one
million gallons. Its watershed is mainly granitic in
character, and occupies about gso square miles in the
northern part of the state of New Jersey. About 3 miles
above the City of Newark, the Belleville pumping-stations
are located, and at this point the supplies of the three
above-mentioned cities are taken. Some 18 miles farther
up the stream is the town of Paterson, a community
almost entirely engaged in the manufalure of paper,
cotton, weollen, and silk goods, locomotives, &c.,and which
throws its entire refuse and the sewage of 50,000 inhabitants
 into the Passaic. Above Paterson there are few
villages and fadories, so that the water going over the
Great Falls at this place is of superior quality for drinking
purposes, Below Paterson manufadtories are gradually
springing up, and are a constant source of uneasiness and
alarm to the large population using the water as pumped
at Belleville. During the course of the year just passed,
one of these factories, an extensive paper-mill, situated
on the Third River, a small tributary emptying into the
Passaic a short distance above Belleville, threw into the
water the refuse derived from washing out some carbolised