Daily Kennebec journal. [microfilm reel] (Augusta, Me.) 1870-1975, 1891-08-20
PHYSICAL Properties Il Mi 4.

The density of milk is dependent
upou the quantity of solids contained in
it AS also on the temperature and con-
dition OF some OF the milk constituents.
r,,e basis for calculating the density OF
fluids is, SAWS Miss Bait, British Ice
turer on dairy subjects, in comparison
with that of distilled water. This den
sitv is expressed in this formula, 600
or 1000 milk is so much heavier than
water, as represented by the formulas
| 03l, which is the average density Of
milk IL roo ounces of water be meas
ured, and the same vessel be
filled TO the same p int with
an equal bulk of milk, the milk
would be found TO be 81 ounces heavier
than the water The comparative dens
jty of new milk ranges from 1O2S to
1881, average 1881. The variable condi
tion of the casein of milk affects the
density to a considerable degree. The
thickness of the cssein envelope sur
rounding the fat globule is alike in all
cases hence the largest globules rise
first and form cream, because they nave
more fat in proportion to caseln. The
smaller the globule the slowe" the rising,
and some very small ones never rise at
ali, because lney aic oNti poieSh' ~
the weight of their Gaseous covering.
The casein envelope explains the varla
ton in speed of the rising Of the fat
globules in milk. The serum or liquid
portion of milk by reason Of its water is
most quickly affected by heat or cold,
but the glohules by reason OF their
Gaseous envelopes respond but slowly
to The influence Of heat or cold. WIN
a falling temperature the fat globule!
rise quickly, because they resist cold
| longer than the serum OF milk. and do
not contract so rapidly; they are there
| fore lighter in proportion and rise rapidly.
| IL, however, the temperature OF mix
remains at II low point. the fat globu'es
contract and increase in gravity, hence
rise slowly. With "A rising temperature,
if reduced by placing milk over heat,
rs in the Devonshire system, current
of air is created, which assists the rising
| of the globules, the lower portion of the
milk getting warm, will rise aud dispiace
the top portion. In this way, the small
est globules, which would not otherwise
rise, are carried up to the surface.
NIscosity in milk is caused by the
presence and proportion of the free
casein 1t r. sists to some extent, the
rising of the globules; the presence OF
other albuminpids also causes viscosity,
by spreading through the milk in very
/ fine invisible network. Sleepy or lazy
milk is generally caused by some sudden
! change in the feeding of the cow pro
ducing gastric arrangement, In sleepy
milk fibrin is present to large degree ;
this causes the cream to rise imperfectly,
and it is difficulty to churn. In some
cases, cream may be churned for hours
| without any result; when in this condi'
ton, it should be thinned with skim
milk or water, being careful to see that
the churn is not oveIflled. The color
or whteness of milk is mainly due IN
the presence Of casein, which can both
re fleet and refract light. The removal
of the fat globules, as cream, lessons the
whiteness but if the fats only are
taken out (as in churning cream into
butter) leaving the casein behind in the
form of buttermilk. the residue is
whittier than new milk Farmers Re-
view.