108 
ON BOILING WATER. 
more so as the oil did not perceptibly absorb the nitrogen freed by the boiling water and 
resting in the bend of the tube; but to meet this conjectural difficulty, the following 
experiment was made :—A tube, 1 foot long and ^-yths inch internal diameter, bent into 
a slight angle, had a bulb of f-inch diameter blown on it at the angle ; this angle was 
about 3 inches from one end and 9 from the other ; a loop of platinum wire was sealed 
into the shorter leg, and the whole tube and bulb filled with and immersed into mer¬ 
cury ; water, distilled and purged of air as before, was allowed to fill the short leg, and 
by carefully adjusting the inclination, the water could be boiled so as to allow bubbles 
to ascend into the bulb and displace the mercury. The effect was the same as with the 
oil experiment, no ebullition without leaving a bead of gas; the gas collected in the 
bulb, and was cut off by what may be termed a valve of mercury, from the boiling 
water, then allowed to escape, and so on; the experiment was continued for many 
days, and the bubbles analysed from time to time ; they proved, as before, to be nitro¬ 
gen ; and, as before, continued indefinitely. 
A similar experiment was made without the platinum wire, and though, from the 
greater difficulties, the experiment was not so satisfactory, the result was the same. 
As the mercury of the common barometer will keep air out of its vacuum for years, 
if not for centuries, there could be no absorption here from the external atmosphere, and 
I think I am fairly entitled to conclude from the above experiments—which I believe 
went far beyond any that have been recorded—that no one has yet seen the phenomenon 
of pure water boiling,— i. e. of the disruption of the liquid particles of the oxy-hydrogen 
compound so as to produce vapour which will, when condensed, become water, leaving 
no permanent gas. Possibly, in my experiment of the decomposition of water by ig¬ 
nited platinum, it may be that the sudden application of intense heat, and in some 
quantity, so forces asunder the molecules that, not having sufficient nitrogen dissolved 
to supply them with a nucleus for evaporation, the integral molecules are severed, and 
decomposition takes place. If this be so, and it seems to me by no means a far-fetched 
theory, there is probably no such thing as boiling, properly so called, and the effect of 
heat on liquids in which there is no dissolved gas may be to decompose them. 
Considerations such as these led me to try the effect of boiling on an elementary liquid, 
and bromine occurred as the most promising one to work upon ; as bromine could not be 
boiled in contact with water, oil, or mercury, the following plan was ultimately devised:— 
A tube, 4 feet long and T 4 <yths inch diameter, had a platinum hoop sealed into one closed 
extremity; bromine was poured into the tube to the height of 4 inches; the open end 
of the tube was then drawn out to a fine point by the blowpipe, leaving a small orifice ; 
the bromine was then heated by a spirit-lamp ; and when all the air was expelled, and a 
jet of bromine vapour issued from the point of the tube, it was sealed by the blow-pipe. 
There was then, when the bromine vapour had condensed, a vacuum in the tube above 
the bromine. The platinum loop was now heated by a voltaic battery, and the bromine 
boiled : this was continued for some time, care being taken that the boiling should not 
he too violent. At the end of a certain period—from half an hour to an hour—the 
platinum loop gave way, being corroded by the bromine; the quantity of this had 
slightly decreased. On breaking off, under water, the point of the tube, the water 
mounted and showed a notable quantity of permanent gas, which on analysis proved to 
be pure oxygen. As much as a quarter of a cubic inch was collected at one experiment. 
The platinum wire, which had severed at the middle, was covered with a slight black 
crust, which, suspecting to be carbon, I ignited by a voltaic spark in oxygen in a small 
tube over lime-water; it seemed to give a slight opalescence to the liquid, but the quan¬ 
tity was so small that the experiment was not to be relied on. No definite change was 
perceptible in the bromine; it seemed to be a little darker in colour and had a few black 
specks floating in it, which I judged to be minute portions of the same crust which had 
formed on the platinum wire, and which had become detached. 
The experiment was repeated with chloride of iodine and with the same result, except 
that the quantity of oxygen was greater: I collected as much as half a cubic inch in 
some experiments, from an equal quantity of chloride of iodine ; the platinum wire, how¬ 
ever, was more quickly acted on than with the bromine, and the glass of the tube around 
it to some extent. 
Melted phosphorus was exposed to the heat of the voltaic disruptive discharge by 
taking this between platinum points in a tube of phosphorus, similarly to an experiment 
of Davy’s, but with better means of experimenting; a considerable quantity of phos- 
