24 R. THRELFALL. 
While weighing nitrogen Lord Rayleigh found he got one density 
when the nitrogen was taken from air, and another when it came — 
from chemical sources. The results of each set of observations 
were consistent, and after trying to explain the discrepancy in — 
every way, Lord Rayleigh fell back on the conclusion that there 
must be some constituent of air hitherto unrecognised. An 
investigation of the basis of our knowledge of the composition of 
air showed that there was a possibility of a small quantity of — 
some other substance existing in it, besides those usually considered. — 
Accordingly the nitrogen and oxygen, water vapour, and carbonic 
acid were successively removed, and Raleigh and Ramsay isolated 
the new substance, to which they have given the name of “argon.” 
It appears to be a singularly inert gas, (to which property it owes — 
its late discovery), heavier than nitrogen, and most probably an 
element, since there is strong evidence that it is monatomic. — 
Should this be the case, room will have to be made for it in 
Mendelejeffs’ series—one can only pray that it may fit a vacant © 
place and not turn the whole of chemistry upside down by refus- 
ing to come in under the periodic law. It would come in if its — 
atomic weight were twenty, but the discoverers think it is forty. — 
However, out of such catastrophes, advances are apt to be made, — 
and if we have to amend our periodic law we shall probably get : 
something better in its place, perhaps some light on the dynamics ; 
I cannot close this brief notice without directing — 
your attention to the magnificent triumph which this discovery 
has obtained for the method of enquiry by means of prolonged, i 
laborious, and exact measurement, as opposed to the method of 
Contrary to the popular idea, the vast : 
majority of discoveries have been made by the methods employed 7 
by Lord Rayleigh, of which the essence is that no obscurity, — 
underlying it. 
happy inspiration. 
however small, is to be passed over until it is completely sifted. 
Another reflection is as to whether this discovery does not illus: — 
trate the deleterious effects of scientific instruction out of text 
books, from which all of us have suffered. It is impossible to go 
into full detail in a text book, and consequently investigations a8 
CS Se fie aaa i 
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