126 PROCEEDINGS OF SECTION B. 
to a matter of pence a gallon; and Pictet appears to have 
some further surprises in store for us, so that it would be 
rash at this stage to put limits to its possible industrial 
applications. But what is of greater interest at present to 
the scientist is its power of producing intense cold, which has 
constituted it a new instrument of research, already attended 
with remarkable success. Through its assistance the valu- 
able physical and chemical researches of Dewar have been 
made possible, and it is interesting to observe that it has 
facilitated to an astonishing degree the study of the com- 
position of atmospheric air itself, these new constituents 
being most readily separated from airin the liquid condition. 
Very great interest attaches to the researches of Dewar in 
his struggle to reach the nadir of temperature ; he has cooled 
helium to 9° absolute, without liquefying it, so that its 
critical temperature must be below that point, its probable 
boiling-point being 5° absolute. Professor Dewar is now 
desirous of getting another gas as much more volatile than 
helium as helium is than hydrogen, to enable him to reach 
a temperature of 1° absolute. May he succeed! His experi- 
_ments are being watched by the scientific world with the 
keenest interest, and by some, if not with full confidence, at 
least with a large hope that he will be able to throw new 
light upon the nature of the molecule. We all want to 
know what will happen when the absolute zero is actually 
reached. If it is ever reached, will the throbbing of the 
solid or liquid atom or molecule be simply stilled for the 
time, or will the vortex-ring or liquid atom vanish into thin 
ether—gravitational matter into non-gravitational matter— 
and a portion of the visible universe be unbuilt? and since 
matter seems to get simpler and simpler as the temperature 
rises, if the zenith of temperature (if such there be) could be 
reached, would something similar happen? So that there 
would be upper and lower 4imits of temperature within 
which alone the visible universe can exist. What will really 
happen we shall find out if we ever get there. It may be 
something very surprising; it will no doubt be something 
very simple and natural, such as we all might have predicted 
had we only thought of it. Just as we shall doubtless find 
when we reach the poles of our earth. 
Looking at the question, however, from the standpoint of 
a chemist—my only standpoint—I cannot but think that it 
shows a want of confidence in the power of human ingenuity 
to piece out the imperfections and limitations of our senses 
by the skilful adaptation of means that nature has placed 
within our reach, to believe that the molecule and the atom 
