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prerogative of the scientific worker in the earlier part of the last century, 
of which Faraday was so pre-eminent an exponent, is no longer our recog- 
nised watchword. I fear I am one of those who are old-fashioned enough to 
lament the way in which our claim to be safe and honest guides of public 
opinion is being endangered—who lament the manner in which the reputa- 
tion of scientific workers is likely to be besmirched if we do not see the evil 
of our ways and mend them. It is impossible to avoid noticing how the 
cancer grows—how the example is spreading among the younger men and 
loose habits of work and thought are being engendered. I know that not a 
few who have laboured steadfastly and seriously in an old-fashioned, exact 
and painstaking way, have been deeply hurt by the manner in which their 
efforts fail to meet with encouragement whilst those who have thrown 
caution to the winds are favoured; the feeling is beginning to arise 
that only sensational discovery is appreciated by the public. We need to 
return to the healthy times when fearless and frank criticism of all work 
was deemed desirable. We cannot substantiate the claims that are made on 
behalf of science unless our own attitude be above reproach—unless we are 
both logical and philosophical—unless we remain the sternest advocates of 
truth in its most rigid form. 
I pass to the consideration of the classification of the elements. The 
recognition of certain properties, the association of certain ideals with the 
several elements, is a necessary step in classifying the elements in accord- 
ance with Mendelejeff’s great generalisation—or rather it may be said to be 
both involved in and an outcome of Mendelejeff’s conception. 
Until recently our difficulty was to understand the relationship of the 
metallic and the non-metallic elements ; now we are confronted with another 
problem—-that of the existence of inert ‘ paraffinoid’ elements. It is com- 
monly assumed that these are monatomic but the evidence on which this 
assumption is based is absolutely unconvincing and would be generally 
admitted to be so were we in the habit of looking before we leapt to con- 
clusions. Assuming that the elements are compounds, the formation of 
inert compounds does not appear to be out of place, in view of the existence 
of practically inert hydrocarbons. But on the other hand, in view of the 
properties of nitrogen, which is one of the most active of substances in the 
monatomic state, although an inert gas in the diatomic condition, it may 
well be that the inertness of helium and the other members of the argon 
group is also simulated. Sir James Dewar’s observations have shown that 
helium and charcoal have no inconsiderable affinity at the boiling point of 
the former, which is within five degrees of the absolute zero, the molecular 
heat of absorption (apart from that due to liquefaction) of helium at that 
temperature being apparently as high as about sixty calories. The proof he 
has given that helium alone does not convey an electric discharge is also 
of significance since the passage of a discharge through it under ordinary: 
conditions is an indication that it can be included with other substances in 
a conducting system. Such evidence as there is therefore points to the 
elements under discussion being different from the others only in the degree 
of stability of their molecules. 
Of late years the difficulty of classifying the elements has been increased 
rather than diminished, not merely because of the discovery of the inert 
gases but also on account of the apparent impossibility of ordering the posi- 
tion of an element such as tellurium in accordance with its atomic weight. 
There appears to be little room left for doubt that the value cannot be far 
removed from that of iodine; it should be considerably lower. It may be 
pointed out that the accepted value of selenium is closer to that of bromine 
than would be expected if a relationship were maintained corresponding to 
that between chlorine and sulphur. It would seem that Mendelejeff’s original 
conception of the elements as a simple series in which the properties are 
