Evening times-Republican. [volume] (Marshalltown, Iowa) 1890-1923, 1909-06-17
Devises New Method of Reading Tests.
[Prof. e. H. Harrington, University of

Devises New Method of Reading Tests.
[Prof. e. H. Harrington, University of
Wisconsin,
One Of the important points in test
ing cream by the Babcock test is to
measure the Pat accurately after 1t is
separated in the neck of the test bot
tie. The bottom of the fat column is
approximately a straight line. but the
top has a concave surface. or menis-
Gus, which often occupies a space of
nearly 1 per cent of the graduated
scale on the neck of the bottle.
Considerable discussion has arisen
as to whether the fat should be read
to the top, the bottom. or to some
other point on this meniscus. Expert
ments have been made by the dairy
division OF the U. S. department Of
agriculture for the purpose of locating
accurately the proper point for read
ing the top Of the fat column.
This uncertainty can be entirely
overcome by dropping small quantity
of alcohol into the neck of the test
bottle after the cream test is COM
pleted. The alcohol floats on the fat
and changes its concave surface to
nearly a straight line. This use OF
alcohol has long been known, but as
alcohol dissolves fat, the practice is
not to be recommended, as 1t reduces
the length of the fat column somewhat
and therefore gives too low a reading
OF the per cent of fat.
Use of Alcohol With Test.
The suggestion has recently been
made by DIR. Babcock that this solvent
o. tjo - oil 60 bo
come by first adding to the alcohol all
the fat 1t will dissolve, and then pour
ing a small quantity of this fat-satu-
rated alcohol on the top Of the fat col
umn In the test bottle. This method
Of reading the fat in cream testing
has been in use for some time at the
Wisconsin dairy school with very sat
isfactory results. The top and the bot
tom Of the fat column appear as near
~ straight lines. giving two exact
points between which the fat can be
measured.
The fat saturated alcohol is pre-
pared by adding about teaspoonful Of
butterfat to six ounces of alcohol in a
bottle. Warm and shake the bottle
until the alcohol has dissolved all the
fat possible: some of it will be left
undissolved at the bottom of the bot
tie. We have found it convenient to
remove the fat saturated alcohol from
the bottle by means of a glass tube
which extends thru the cork to near
the bottom of the bottle. By placing a
finger over the top and lifting the tube
out of the bottle, small quantity of
the liquid can readily be transferred
Ito the cream test bottle.
This fat saturated alcohol should be
used for reading the tests as soon as
they are completed, while the fat is
still liquid. A little shaking Of the
test bottle after adding the alcohol
will sometimes make the line between
the fat and the alcohol more distinct.
Sodium Arsenic for Canada Thistles.
[By Prof. H. L. Bolley.1
On account of the statements in our
Bulletin 80 regarding the value of so
dunn arsenite as a destroyer of Can
ada thistles, there has been a big de-
mand for that chemical. We published
those statements after comforting with
a number of wholesale chemical
houses to learn whether sodium arsen-
lite could be procured. We are told
that 1t could be procured in any guam
tity and at cheap rates. Since that
bulletin has been published it has been
Impossible for local drug stores to pro-
cure crude sodium arsenite which is
anything near the regular strength
Sometimes the product will show as
high as SO per cent Of sodium arsen-
late, which makes it nearly worthless
as a weed killer and makes 1t undesir-
able to attempt to use 1t as genera,
spray over cereal grain fields because
the arsenate Is insoluble and injurious
Ito grain, while pure arsenite as recon-
mended does no harm. have made
every effort to have the wholesale
; druggists and manufacturers Of chem
icals understand the value OF arsenit<
as weed killer and to have then
make arrangements to put a standard
product on the market. have every
reason to believe that they have faith.
fully tried to do this, but as yet, be.
cause they have never before had sucl
large demands for arsenite, they art
-1unable to meet the requirements for {
commercial grade Of arsenite that 1!
reasonably pure.
People who are Interested In killing
Canada thistles should give sodium ar.
senite at least trial in small way
this year so that they can learn the
efficiency Of the matter
4 II they do get high grade Of so
dunn arsenite, they will have sucl
good success with the killing OF th,
thistles that the work Is sure to b.
tcontinued In the future. Our expert
lments show that one and q half pound
y &