AUGUST 25, 1899. ] 
menter is the overcoming of difficulties and 
the possibility of new discoveries which 
come as surprises. In the case in question 
a liquid of extremely low density, only 
ene-fourteenth that of liquid nitrogen, was 
produced, while still defined by clear and 
well-marked refracting surfaces. 
When we turn to the consideration of the 
field for research work at high tempera- 
tures we are not confronted by the fact of a 
physical limit existing which may be ap- 
proached but never reached. We can 
imagine no limit to possible increase of 
temperature, such as is the absolute zero a 
limit of decrease. While we may actually 
employ in electric furnaces temperatures 
which, according to Moissan, have a lower 
limit of 3,500° C., we can realize the possi- 
bility of temperatures existing in the stars 
measured by tens of thousands or hundreds 
of thousands of degrees of our temperature 
seale. : 
The moderate increase of working tem- 
perature given by the electric furnace 
enabled Moissan and others to reap a rich 
harvest of experimental results, and the 
natural inference is that much more might 
be expected from further extensions of the 
limits. These limits are, however, already 
set for us by the vaporization of all known 
substances. Our furnace itself keeps down 
the temperature by melting and volatilizing. 
We may indefinitely increase the energy in 
an electric arc and thus add to the heat 
evolved, but the addition only goes to va- 
porize more material. The limit of work 
then seems to be readily reached in the 
electric furnace, no materials for lining be- 
ing available, not subject either to fusion or 
vaporization, thus using up the energy 
which would otherwise go to increase the 
temperature. 
A suggestion as to a possible extension of 
temperature range may be made here. It 
may be requisite to work with closed re- 
ceptacles under pressure, and to discharge 
SCIENCE. 
237 
through them electric currents of so great 
energy-value as to attain almost instantane- 
ously the highest temperatures, to be main- 
tained for only a very short time. We may 
imagine a huge condenser charged to a po- 
tential of, say, 10,000 volts as discharged 
through a limited body of gas contained in 
a small space within a strong steel tube 
which has a lining of refractory non-con- 
ductor. The energy may thus possibly be 
delivered so suddenly to avery limited body 
of material as to result in a momentary 
elevation of temperature passing all present 
known limits and capable of effecting pro- 
found changes in molecular constitution. 
We need all possible extension, of the limits 
of research in this direction in order to dis- 
cover some clue to the relations which the 
chemical elements. bear to each other. The 
limit of possible strength of the containing 
receptacle, or some unforeseen factor, would 
probably set the new bounds. The point to 
be here enforced, however, is that far be- 
yond any increase of working range in tem- 
perature, obtained in any way, there must 
still exist a further range unattainable by 
our best efforts and possibly forever outside 
of the field of experimental research. Our 
knowledge of this higher range can alone be 
derived from a study of the actions going 
on in the stars and nebule. 
As with the temperature range so it is 
with the pressure range. We may easily 
work under conditions which involve no 
pressure, but when we attempt to conduct 
our inquiries with increase of pressure 
we soon find a limit to the tenacity of 
our strongest vessels or to our ability to 
produce and maintain extreme pressures. 
We may work, not easily it is true, with 
pressures up to a few tons to the square inch, 
but this is as nothing compared to the con- 
ditions which we know must exist within 
the larger celestial bodies, without reference 
to their condition, solid, liquid or gaseous. 
Can we ever hope to experimentally repro- 
