1854.] OF THE ROYAL INSTITUTION. 447 
from water by persistent boiling, such water possessess an ex- 
traordinary cohesive power, sufficient indeed to permit of its 
being heated to a temperature of 275° Fah. without boiling. 
The adhesion of water thus prepared to the surface of a glass 
tube was shewn experimentally ; the force being sufficient to 
sustain a column of water of considerable height. The contractile 
force of a soap-bubble was referred to; and the Lecturer passed 
on to the exhibition of the phenomena resulting from the shock 
of two opposing liquid veins. In this case, though the forces 
are in opposite directions, motion is not annihilated ; but the liquid, 
as first shewn by Savart, spreads out so as to form a thin trans- 
parent film, the plane of which is at right angles to the direc- 
tion of the jets. By varying the pressure on one side or the 
other, or by making the jets of different diameters, the plane film 
could be converted into a curved one, and sometimes actually 
caused to close, so as to form a pellucid sack. A cistern, situa- 
ted at the top of the house and communicating by pipes with 
the lecture table, placed a considerable pressure at the disposal of 
the Lecturer, and enabled him to exhibit in a striking manner 
the various phenomena described by Savart in his researches on 
the motion of liquids. A vein was caused to fall Vertically upon 
a brass disk upwards of three inches in diameter: the liquid 
spread laterally on all sides and formed an umbrella-shaped 
pellicle of great size and beauty. With a disk of an inch in 
diameter, a pellicle of at least equal magnitude was formed. 
When a candle was placed underneath the curved sheet of water 
a singular effect was produced. The film above the candle was 
instantly dissipated ; and on moving the candle, its motion was 
followed by a corresponding change of the aqueous surface. 
On turning a suitable cock so as to lessen the pressure, the 
curvature of the film became increased, until finally the mole- 
cular action of the water caused it to form a curve returning 
upon itself, and exhibiting the appearance of a large flask. 
When the film completely embraced the vertical stem which 
supported the brass disk, a change in the form of the liquid 
flask was observed, the latter became elongated, and was some- 
times divided into two portions, one of which glided down the 
vertical stem and was broken at its base. When the jet was 
projected vertically upwards, large sheets were also obtained. 
The jet was also suffered to fall into small hollow cones of Various 
apertures, and the shape of the liquid sheet received thereby 
some beautiful modifications. The inclosed sides of the hollow 
cone gave the liquid an ascending motion which, combined with 
the action of gravity, caused the film to bend and constitute a vase- 
shaped surface of great beauty. The Lecturer next referred to the 
constitution of a liquid vein; he had pointed out, some years 
ago, a simple mode of observing this constitution by means of the 
