Rogue River courier. (Grants Pass, Or.) 1886-1927, 1908-11-13


study the problem from a later
stage, namely, the period of the
chilled fiber. While is not definitely
known what action during frost
causes the death of the cell tissues
whether it be rupture OF cell walls
or separation and withdrawal OF
water content. it would seem that we
could not err in guarding the plant
fiber from any strain due to rapid ana
unequal heating when in chilled
condition. Beginning before sunrise,
some screen or covering should be
interposed between the fruit and the
SUMS rays. For the reasons given
above it is also advisable to apply
water. 1t may interest fruit growers
to point out to them that the actual
temperature of the air is probably OF
less importance III frost formation
than the cooling of the plant surface
due to radiation. Nearly all fruit
growers now understand that after
sunset, if there be no clouds present
and but little motion Of the air
Though it is well to test this by
watching the flow of smoke near the
ground) the plant surface emits heat
rapidly into space. The under surface
of the foliage, of course, intercepts
heat from the ground, and so we sell
dom tind frost forming under tree.
The connective currents of the air are
generally sluggish and there is as
rule, little mixing of the air strata,
or no thorough circulation at such
times. Helmholtz has shown that
LAYERS of air of different temperatures
may lie close to one another without
mixing, and indeed this Is known to
be the case, not only near the ground
but even in free air. Doubtless here.
10 lies the explanation OF the streaki'
ness of frost. We have examined or
chards which were apparently level (;
and yet upon close inspection it was
found that although there was no
noticeable slope OF the ground, there
were certain channels of air motion
and certain stsgnsnt zones. The frost
streaks wers found to coincide with
the stsgnant areams. Much, however,
depends upon the nature of the radiat'
ing surface.
The warming or the chilling OF the
ground has not much effect upon the
air at ~ distance of 10 or 10 feet
That is to say, the rate OF heat con-
duction from one layer to another is
very slow. Therefore it is not un-
usual on frosty nights to obtain
readings of 80 degrees F. at the
ground, while at six to 10 feet above
the eround. the temperature may be
81 degrees or 3S degrees f.
Under the third head, viz, the con-
siruction of devices and apparatus
for use in orchards, vineyards, gar.
dens, etc., we believe that each local
forecaster can contribute materially to
successful work by examining in situs
anv device brought to his notice. 1t
is suggested that he read mp the
history OF the wire coal baskets, first
used by Edward Copely at Riverside,
Cal, the use of oil by Evertt at Ar.
lington; the application of hot water,
first used by Meschsm; the smudge
machines of Hall, Hammond and
Others the oil pots and the small,
cheap, sheet iron stoves in which
brlquettes are burned and which are
now on the market The methods OF
protection by covering, whether cloth
or lath, should be looked into. The
question of expense will determine the
availability of the method. In Cali
fornia the diversity of interest is sc
great that no general recommenda-
ton, can be given, and in each To-
cality the local forecIster should I'll
the method to the fruit. In the
Riverside, Redlands, Cotton sectior
the orange naturally claims first at.
tention; at San Diego, both lemon,
and oranges; in the foothills of the
San joaquin. oranges; in the valleys
the raisin vines in the spring; lnstht
Sacramento valley, the garden truck
in the bay valleys, the almonds
against the late spring frosts; aud il
Northern California, the deoiduou
fruits. In all directions there is room
for Improvement And not only
10 tb. construction of apparatus, bu
IN the manner Of application. Par.
ticlarly valable are cases where ap
parently effective devices fail to &C
complish the desired protection. Sucl
cases shield be studied and the reason
for the failure ascertained Thi
constitutes progress Under IN,
fourth heading-the use of our know
ledge so that maximum good ma,
result-much of what has been sal,
above is applicable. -As--an illustra