Experimental Inquiries respecting Heat and Vapor. 307 
At temperatures considerably below that of most rapid vapori- 
zation, there was constantly exhibited, in the various series of experi- 
ments, a decided tendency in the water to adhere to the metallic 
surface, and when by contact with a given portion of surface, and by 
receiving and rendering latent in vapor, the heat which the latter had 
possessed, the temperature of that portion was somewhat reduced, 
the stratum of water was observed to glide away to other, hotte 
parts of the surface, even against the force of gravity. 
This effect was observable in the cylinders with which the second 
course on variable rapidity, was performed. ‘Towards the conclu- 
sion of each series, the water, after ceasing to boil in the bottom o 
the cylindrical cavity, ascended in many instances quite to the top of 
the cylinder, and even spread outward on all sides wherever it met 
with a higher temperature than 212°. 
The same phenomenon was noticed in the basin already described, 
and in the bar above mentioned. ‘To make this effect the more dis- 
tinct, a broad shallow pan of extremely thin iron, commonly called 
by the tin plate workers, “ black tin,” was procured. In the centre 
of this, a slight elevation, about one tenth of an inch high, was made, 
with a Corresponding cavity on the under side, or bottom of the pan. 
A lamp being applied beneath the elevated part, the iron soon ob- 
lined a dull red heat in the dark. Water was then laid upon the 
basin so as to surround completely the centre, and form a sort of 
island of heated surface. As the heat extended by degrees, and 
reached the line of water, the latter was observed to start 
fromm its line, and moisten a portion of the surface not before wetted. 
By agitating the water with a hair pencil, and creating a wave 
towards the centre, the line of vaporization became distinct. By 
raising the waves still higher, that of repulsion was manifest, and by 
Causing a surge high enough to break quite over the insulated eleva- 
lon, the alternate attractions and repulsions were seen in the drops 
ind masses which, having been driven forcibly beyond the first line 
of Vaporization, or that which they encountered on their ascent, were 
subsequently rolled quite over the centre of the elevated embossment, 
‘arrested with great promptitude as they rolled down and reached 
ine of vaporization on the opposite side. ‘oan 
3. In order to ascertain the influence of certain lubrications in re- 
ducing the rapidity, I placed the bar over a spirit lamp in such a 
manner as to bring two of the mercurial reservoirs, and their adjacent. 
“tps at equal distances from the centre of flame. Having allowed 
