UNSOLVED PROBLEMS OF SCIENCE. 37 



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 consequently they combine in fixed ponder- 

 able 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 com- 

 pacted by some strange machinery into one. The most elaborate 

 analyses, conducted by chemists of the highest eminence con- 

 spicuously 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 spectrum analysis, and men 

 thought that with an 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. Spectrum analysis in 

 the hands of Dr. Huggins and Mr. Lockyer and others has taught 

 us things of which the world 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 ; we have learned 

 the pace the fabulous pace at which the most familiar stars 

 have been for ages approaching to or receding from our planet, 

 without apparently affecting the proportions of the patterns 

 which, as far as historical record goes back, they have always de- 

 lineated on the evening sky. We have received some information 

 about the elementary atoms themselves. We have learned that 

 each sort of atom, when heated, strikes upon the ether a vibra- 

 tion, or set of vibrations, whose rate is all its own ; and that no 

 one atom or combination of atoms, in producing its own spec- 

 trum, encroaches even to the extent of a single line upon the spec- 

 trum that is peculiar to its neighbor. We have learned that the 

 elements which exist in the stars, and especially in the sun, are 



