6 REPOKT — 1894. 



four of the most important physical questions which it has been the effort 

 of the last century to solve. 



Of the scientific enigmas which still, at the end of the nineteenth 

 century, defy solution, the nature and origin of what are called the 

 elements is the most notable. It is not, perhaps, easy to give a precise 

 logical reason for the feeling that the existence of our sixty-five elements 

 is a strange anomaly and conceals some much simpler state of facts. But 

 the conviction is irresistible. We cannot conceive, on any possible 

 doctrine of cosmogony, how these sixty-five elements came into existence. 

 A tliird of them form the substance of this planet. Another third are 

 useful, but somewhat rare. The remaining third are curiosities scattered 

 haphazard, but very scantily, over the globe, with no other apparent function 

 but to provide occupation for the collector and the chemist. Some of them 

 are so like each other that only a chemist can tell them apart : others differ 

 immeasurably from each other in every conceivable particular. In co- 

 hesion, in weight, in conductivity, in melting-point, in chemical proclivities 

 they vary in every degree. They seem to have as much relation to each 

 other as the pebbles on a sea beach, or the contents of an ancient lumber 

 room. Whether you believe that Creation was the work of design or of 

 inconscient law, it is equally difficult to imagine how this random collection 

 of dissimilar materials came together. Many have been the attempts to 

 solve this enigma ; but up till now they have left it more impenetrable 

 than before. A conviction that here was something to discover lay beneath 

 the persistent belief in the possibility of the transmutation of other metals 

 into gold, which brought the alchemy of the Middle Ages into being. 

 When the immortal discovery of Dalton established that the atoms of 

 each of these elements have a special weight of their own, and that con- 

 sequently they combine in fixed ponderable proportions from which they 

 never depart, it renewed the hope that some common origin of the elements 

 was in sight. The theory was advanced that all these weights were 

 multiples of the weight of hydrogen — in other words, that each elementary 

 atom was only a greater or a smaller number of hydrogen atoms compacted 

 by some strange machinery into one. The most elaborate analyses, con- 

 ducted by chemists of the highest eminence — conspicuously by the 

 illustrious Stas — were directed to the question whether there was any 

 trace in fact of the theoretic idea that the atoms of each element consist 

 of so many atoms or even of so many half-atoms of hydrogen. But the 

 reply of the laboratories has always been clear and certain — that there is 

 not in the facts the faintest foundation for such a theory. 



Then came the discovery of the spectral analysis, and men thought 

 that with 8.n instrument of such inconceivable delicacy we should at last 

 find out something as to the nature of the atom. The result has been 

 wholly disappointing. Spectral analysis in the hands of Dr. Huggins and 

 Mr. Lockyer and others has taught us things of which the woi'ld little 

 expected to be told. We have been enabled to measure the speed with 

 which clouds of blazing hydrogen course across the surface of the sun : 



