Vermont farmer. [volume] (Newport, Orleans County, Vt.) 1870-1877, 1874-03-13


cultivation of the grape, afhrms that bleed
ing in the spring does not exert the slightest
influence upon the vine. In order to deter
mine this point he selected fifty Concord
vines in his vineyard, and pruned one every
day from the first Of May until the young
shoots we're well grown, and 80 demonstrated
to his satisfaction that il made no difference
when vines were pruned provided It be done
before the development Of the new growth.
IL only remains to state in a few words
the surprising results obtained by the appli-
cation Of mercurial gauges to the sugar-ma.
pie, the black.birch and the grapevine. OBJ
servatious we're made on one or more guages
several times daily, and occasionally every
hour Of the day and night, from the LIST Of
April to the 20th of July.
A gauge was attached to sugar.maple
March 3lst, which was three days after the
maximum flow OF sap for this species, so that
further observations are required earlier in
the season to complete the record and deter
mine with certainty the maximum pressure
which it exhibits in the spring. Of the rec
ord made, the following facts are especially
interesting first the mercury was subject to
constant and singular oscillations, standing
usually in the morning below zero, so that
there was indicated powerful suction into
the tree, and rising rapidly with the sun, un-
til the outward pressure was sufficient to sus.
tain column of water many feet in height.
Thus at I A. NJ, April Dist, there was n sue
ton into the tree sufficient TO raise column
Of water % 80 feet As soon as the morn
ing sun began to shine on the tree, the mer-
curry suddenly began to rise, so that at 9.15
A. NJ, the pressure outward was enough to
sustain a column of water l8.47 feet high,
change represented by more than "A feet of
water. On the morning Of April 22d the
change was still greater, requiring for its
representation AZ AZ feet Of water. These
extraordinary fluctuations were not attended
by any peculiar state of the weather, and
happened twelve days before there were any
indications of growth to be detected in the
buds These observations are believed to be
quite new, and as yet inexplicable, but will
receive further attention another spring
The maximum pressure of the sap for the
season was observed at 10 NJ. April llth,
and was equal to sustaining a column of wat
er 3l.73 feet high. This was an excellent
sap-day, considering the lateness Of the sea
son. There was noticed general CORES.
pondence between the flow of sap in other
NAPLES and the pressure on the gauge.
After April 10Th the mercury remained
constantly below zero, day and night. Dur
ing the month of May there was a uniform
suction equal to about eight feet of water,
and the unaccountable feature of this fact
is, that though apparently produced by ex-
halation from the expanding leaves, it re-
manned the same, day and night for several
weeks In June the suction gradually less
oned, aud finally disappeared, the mercury
standing steadily at zero
On the 10Th of April two gauges were at.
tached to large black birch, one at the
ground and the other thirty feet higher.
The next morning at six O'Clock the lower
gauge indicated the astonishing pressure of
$685. feet Of water, and the upper one, OF
26.74 feet The difference between the in
dications of the two gauges was thus 1892
feet, while the actual distance between them
was 1920 feet, so that it correspondent al
most exactly as if they were connected by a
tube. In order to learn whether the same
principle would prevail if the upper gauge
was moved. it was raised twelve feet higher
The same correspondence continued through
nearly all the observations Of the season, not.
withstanding the gauges were separated by
~ 20 feet Of close. grained brentwood.
7 At 1880 p. NJ, April Dist, a hole was
bored into the tree on the side opposite 10
the lower gauge, and at the same level. Both
gauges at once began to show diminished
pressure, while sap issued freely from the
| In e
having escaped it was found that both gaug.
es had fallen equal to 1927 feet Of water.
Upon closing the hole the gauges rose in ten
minutes to their previous level. showing that
the rootlets had re-absorbed in that brief
period the sap which had escaped from the
tree, Notwithstanding the enormous pressure
already existing
A stopcock having been inserted into the
hole opposite the lower gauge, it was found
that the communication between it and the
{ two gauges was almost instantaneous, which
appears TO prove that the tree was entirely
filled with sap, exerting its pressure in all di-
rections as freely as if standing in a cylIn.
drical vessel more than sixty feet iD' height
as indicated by the lower gauge. The sap.
pressure continued to Increase until, on the
llth day of May, it represented a column OF
water SAT- feet il height, which is believed
to be the highest pressure of vegetable sap
ever recorded.
The buds of the birch now began to ex.
pand, the pressure of the sap to diminish
aud the oscillations of the mercury to be.
come more decided and regular than before
The upper gauge ceased to vary May 18th
remaining stationary at zero. The lower one
declined slowly and varel greatly, but did
not fall below zero until May 18th. On
May 9th it also became stationary at zero
The suction manifested by the birch was very
little, never exceeding nine feet of water,
and continued only for few days.
To determine, If possible, whether any
other force than the vital action of the roots
was necessary to produce the extraordinary
phenomena described, a gauge was attached
to the root of black birch-tree, as follows
The tree stood in moist ground, at the foot
of the south slope Of ravine, in such sit.
uation that the earth around it was shaded
by the overhanging bank from the sun. A
root was then followed from the trunk TO the
, distance Of ten feet, where il was carefully
cut off one foot below the surface, and a
piece removed from between the cut and the
> tree. The end Of the root thus entirely de.
tached from the tree, and lying in horizon
, tai position at the depth Of one foot, in tbs
cold, damp earth, uureached by the sunshine
aud for the most part unaffected by the TEN
3 perature of the atmosphere, measured about
: one inch in diameter. To this was carefully
adjusted mercuria gauge, April 10Th. The
pressure at once became evident and rose
constantly with very slight fluctuations, un
til, at noon on the Both Of April, it had at
tanned the unequaled height of S5,S0 feet o
. water. This wonderful result showed that
the absorbing power OF living birch rootlets
without the aid of any of the numerous help