FREE INSTITUTE OF SCIENCE 



ETHER WAVES AND THE MESSAGES THEY BRING 



75 



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ment of the atoms in the planes. For instance, if a crystal of sodium chlorid 

 be cut so that the surface lies in a plane parallel to any of its three axes, the re- 

 flected rays show that the surface is composed of equal numbers of sodium and 

 chlorin atoms. If, however, a surface be made in a plane cutting off equal 

 intercepts on the three axes, we find the surface to be composed entirely either 

 of sodium or of chlorin atoms. The diagram on the screen (Fig. 6) shows 

 the only arrangement of atoms which will fulfil these conditions. The dots 

 may be considered as representing chlorin atoms, while the rings represent 

 sodium atoms. It will be seen from the diagram that instead of any one sodium 

 atom being associated with a particular chlorin atom, as 

 would be supposed from the chemical symbol for the 

 molecule, it is associated equally closely with any of 

 six such atoms. Thus the notion of molecular struc- 

 ture as applied to crystalline solids apparently does not 

 hold, but is replaced by a mass structure in which the 

 proportion only of the elements is indicated by the 

 chemical formula. About forty inorganic crystalHne 

 substances have been studied, and in each case similar 



results have been obtained. There is no evidence, however, that these results 

 hold for organic or for non-crystalHne substances. Just what future develop- 

 ments along these lines may bring forth cannot be predicted. 



It will be seen from what has been set forth that all these manifestations 

 of energy in the ether have been reduced to a single form of wave motion, since 

 they differ essentially only in wave length and in frequency. This work consti- 

 tutes one of the two greatest achievements in science during the past hundred 

 years. As a result of it the electromagnetic theory of hght has been firmly 

 established, and many apparently diverse problems have been merged with 

 those greatest of mysteries confronting physical science — the nature of ether, 

 and the structure of, and the relations between, matter and electricity. 



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Fig. 6. — Diagram 

 showing arrangement of 

 atoms in crystal of sodium 

 chlorid. 



