precipitin test for human origin, or to
ke acblood group test. It has been known
it a stain as small as a dime has been suc-
sfully “typed” or blood-grouped, but
s would be rather the exception than the
le. Usually larger amounts would be re-
ired for this purpose. The age of the
in also is a determining factor, and there-
re it is only logical that where a case is-of
fficient importance, nothing should be
erlooked and specimens sent in for what
ey may be worth.

* *

UESTION: “Is there a handy method of
‘termining whether a coin is spurious or
nuine?””

NSWER: Yes there are a number of
ays of determining counterfeit coins. As
ost of the spurious coins are made from
ibbit metal, it will be noted that they have

“soapy feeling when rubbed between
ie thumb and forefinger. An examination
‘the milling around the edge of the coin
ill often show a “flat spot” or if the
yunterfeiter is a little more careful, he may
ive filed in a few nicks to resemble the
gular milling. These, however, usually
ffer from the general milling around the
yin. The “flat spot” is left by the “sprue”
hich is left after the coin has been poured
ito the mold. This is cut off with a knife,
rd leaves a mark. In a genuine coin there

no such mark as the mint “strikes” its
ins between metal dies.

Other factors are: The “ring” of the
yin, counterfeits having a dead sound; the
1arpness of the design on obverse and re-
erse; hardness, the counterfeit being usually
uite soft and readily cut with a knife,
ad so on.

However, the most useful and rapid
ethod of determination, is by a simple
nemical process. A solution of nitrate of
lver, nitric acid and distilled water is all
vat is required. A drop of this solution
r detector” on a silver coin will leave no
ark at all, but if applied to a coin of base
etal, there will be an immediate blacken-
1g of the spot to which the mixture has
een applied. The formula is as follows:

Nitrate of silver—24 grs.
Nitric acid—30 drops.
Distilled water—1 oz.

JUESTION: “What is the meaning of the
rms “Alcohol by weight’ and “Alcohol
y volume’ in an Analyst’s Report?”

\.NSWER: These are two different sys-
sms of measuring the amount or percentage
f alcohol in a liquid. Alcohol is only about
/5 the weight of water. It follows there-
ore that if 100 c.c.’s of a liquid, contains

1

BILL RICKSON
Men’s Wear
e

Union Street Courtenay, B. C.

HIRTEENTH EDITION

1 _c.c. of alcohol, it will have a percentage
of “19% alcohol by volume.” However, as
the alcohol does not weigh as much as the
water (the specific gravity of alcohol being
-7936) the percentage of alcohol by weight
will be much smaller.

In this instance, the 100 c.c.’s of liquid
will weigh slightly less than 100 grams.
The alcohol will weigh .7936/10000 of a
gram, so that the percentage of “alcohol by
weight” will only be .7936%, instead of
1% “alcohol by volume.”

There are other very interesting facts
concerning the analysis of alcohol which are
not generally known. One of them is the
“solubility” of alcohol in water. A mixture
ot say 50 oz. of absolute alcohol and 50 oz.
of water, will not give 100 oz. of the mix-
ture. There will only be about 96 ozs.
Four ounces have dissolved in the water, etc.
The only comparison that one can readily
make, is to take a cubic yard of sand and a
cubic yard of coarse gravel. The two mixed
together will not yield two cubic yards of
material, because a great deal of the sand
will fill in the spaces originally existing in
the cubic yard of coarse gravel, and so give
a smaller total volume.

It is also an interesting fact that Ameri-
can standards and British standards of al-
coholic percentage differ. The American
standard shows a higher alcoholic percentage
of a given liquid than the British.

The main difference lies in the fact that
where the British standard would show the
liquid to 100% proof spirits, the same liquid
using the American standard would show
it to be 114.2% proof spirit, by volume.

The British proof spirit contains 57.1%
absolute alcohol by volume or 49.2% alco-
hol by weight. The term “proof spirit”
has an interesting history. In the old days,
when the British Naval Authorities were
examining shipments of spirits into England,
they used a rough-and-ready method of de-
termining the alcoholic content. A small
pile of gunpowder was placed on-an anvil,
and a little of the liquid was poured on it.
A red-hot poker or “match” was passed
over the soaked powder. If the alcoholic
fumes were sufficiently strong, the whole
mass would ignite. On the other hand if
the liquid was predominently water, the
powder would be too wet to ignite.

While this does not form part of the
question, it might be of interest to know
the reason why methyl alcohol, or wood
alcohol is dangerous to human life. The
methyl alcohol itself does not kill, but upon
combining with the hydrochloric acid in the
stomach, formaldehyde is formed. In acute
cases of wood alcohol poisoning, formic acid
is found-in the urine. Formaldehyde de-
stroys the weakest tissues in the body, in-

cluding brain, sheathing of the optic nerves ,

and so on. Wood alcohol should not be
used as a rubbing alcohol. :

There is insufficient space in this section
for a discussion of the alcohols, but if this
subject is of interest to our readers, a com-
plete article will be prepared in a future
issue.

QUESTION: “What are the fundamental

points to watch for in checking Canadian

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Phone 357 P. O. Box 143

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Also Dealers in
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COURTENAY, B.C.

Page Thirty-one