62 PRESIDENTS ADDRESS—SECTION B. 
attribute to the fact that the search for minerals has been almost 
entirely directed to the finding of gold or other payable metals. 
We have heard a good deal of Broken Hill, perhaps there are 
some listening to me who are fortunate or unfortunate enough to 
know more about it than by mere hearsay, but it is scarcely to 
be doubted that a careful scientific search for and examination 
of minerals from the great silver field would yield results of great 
interest. Professor Masson and Mr. Kirkland have, I under- 
stand, examined a considerable number of zinc ores from that 
district for gallium, but so far without success. I have roughly 
examined the flue dust from the Dry Creek Smelting Works for 
germanium, but so far without finding any, but these negative 
results need not discourage us. You may be reminded in this 
connection that the Government assayer of N.S.W. reports 
the discovery of platinum, and probably therefore some of the 
associated metals in some minerals from somewhere in the Broken 
Hill region. 
This department of chemical science—I mean the search for 
new or imperfectly known elements—has acquired great interest 
and importance in view of the great impulse recently given to the 
study of the periodic law of Newlands and Mendeléeff by various 
chemists in Europe and the brilliant researches of Crookes on the 
nature of several of these so-called elements. It may not be out 
of place before bringing this address to a conclusion to review 
very briefly the more important results obtained in this direction 
during the past few years, the questions involved being of all- 
absorbing interest to both chemists and physicists. It is evident 
that, whether justified by facts or not, there is a growing disbelief 
in the elementary character of the so-called elements, and this 
disbelief has arisen from results obtained in two different lines of 
research, namely, a more thorough study of the periodic law, and 
the spectroscopic investigations of Crookes and others. 
One of the most important papers on the periodic law was that 
read before the British Association at Aberdeen, in 1886, by 
Carnelley. He brought out very clearly the analogies between 
the elements so called when arranged according to the periodic 
law and series of hydrocarbon radicles and their derivatives, and 
showed that it is possible to build up a series of compounds of 
two primary elements corresponding in many respects to the known 
series of elements, and he advances the speculation that all of the 
latter, except hydrogen, may be compounds of two substances, 
one with atomic weight 20, and the other with atomic weight — 2, 
the latter being identical with the e¢#er which exists all through 
space and matter as the medium of transmission of heat and light. 
Dr. Carnelley puts this forward merely as a speculation, and though 
the idea of a substance with negative atomic weight may be to 
others, as to myself, very difficult to grasp, there can be no doubt 
