4 i 6 Dixon and Joly. — The Path of 
the clear liquid in the lumina assuming the aspect of solid 
paraffin. In two experiments in which the reduction of 
temperature was effected very gradually the freezing-point 
was found to lie between — io° and — 1 1° C. Freezing spread 
with great rapidity all over the field in both wide and narrow 
lumina. Air-bubbles present exhibited immediate reduction 
of volume and often distortions of shape, and it was important 
to observe that an exudation of sap occurred upon bare cell- 
walls which appearing in drops instantly turned to rough- 
shaped ice-crystals. 
Thawing occurred at a higher temperature than freezing, 
no signs of melting being exhibited till — 4 0 or — 5 0 were 
reached. This specimen of wood was removed from a branch 
which had been standing some days in water. A freshly cut 
branch of Taxas afforded 14-5° as the freezing-point ; showing 
that the state of the sap appears to affect the freezing-point 
considerably. 
Owing to the pressure-effect of the ice upon the wall visibly 
shown by the forcible expression of drops, there appeared 
some doubt whether this method would afford any result of 
value. However, the experiments were persisted in, and a 
length of 22 cm. by 6 mm. in diameter of a Taxus-twig, carefully 
washed, was attached to the apparatus shown in Woodcut 7, in 
which the passage of liquid through the vertically placed stick 
(due to a diminished air-pressure in the vessel above) is shown 
by the movement of mercury in the horizontal capillary tube. 
