360 BOTANICAL GAZETTE [MAY 
In this experiment, therefore, and at the height in question, our 
plant exhibited shoot suction when tested by the pinometer. A 
modified barograph recording cylinder, made by NEGRETTI & ZAMBRA, 
was arranged to record the rise of the mercury in this particular 
experiment. A burette-float was placed on the mercury in the open 
end of the gauge (/). It was suspended by a fine thread, which ran 
over a pulley and was attached on the other side to the free end of a 
lever, the other end of which carried a pen which wrote on the revolv- 
ing cylinder. The records taken during the first week showed that 
the water taken in from midday to midnight and that taken in from 
midnight to midday was in the proportion of three to two. Never 
did any pressure from the root, during night or day, cause the 
amount of water taken in to fall below nought. 
In a second experiment a pinometer was fixed into a fuchsia 
plant about one inch above the soil and quite below the lowest lateral 
shoot. Root pressure manifested itself very soon and the mercury 
was forced out of the inner limb of the gauge, rising of course as 
rapidly in the outer one. In this case there was obviously pressure 
on the cut surfaces of shoot and root. The leaves of the shoot kept 
fresh as long as the pressure lasted, which was for sixteen days. 
On the sixteenth day there was a difference in the level of the mer- 
cury in the two limbs of the gauge of 20™™. Allowance however 
must be made for the column of water resting on the mercury in the 
inner limb of the gauge. After the sixteenth day the pressure was 
gradually reduced, very probably owing to the root becoming exhaus- 
ted, its supply of organic food from the green leaves being cut off. 
The leaves began to wither as the pressure of the root decreased. 
In a third experiment two pinometers were employed (/ig- 2 ). 
One was fixed to the fuchsia plant just above the soil and the other 
just above the lowest lateral shoot. The plant was therefore cut into 
three parts, the lowest one of which, the stump, was devoid of any 
lateral shoots. The gauge attached to the lower pinometer (P;) Very 
soon indicated pressure from the root, that of the upper pinometer 
(P,) suction from the two portions of the shoot. We have therefore 
in this experiment an arrangement by which root pressure and shoot 
suction can be observed at the same time. The difference in the 
appearance of the leaves on the two portions of the shoot is very 
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