CARBON 



3i 



Moseley {Phil. Mag. 1913 [vi], 26, 1024; 1914 [vi], 27, 703) 

 applied the photographic method of X-ray spectra to the study 

 of crystal structures. 



Barlow (Proc. R. Soc. 1914, A623) discussed Bragg's conclu- 

 sions from the crystallographic point of view. 



Ewald {Phys. Zeits. 1914, 15, 399), criticising Bragg's reflection 

 method, described a new method based on the study of Laue- 

 graphs for the accurate determination of the crystal structures. 



Hans Meyer {Monatsh. 1914, 35, 163), discussing the carbon 

 "molecule," puts stress on the difficulty, if not the futility, of 

 trying to define the chemical entity of the three forms of carbon. 



It is clear from the above that a method of investigation so 



Fig. 4. 



general as to include simultaneously all three forms of carbon 

 has not yet been proposed. Whilst the method of moist oxida- 

 tion can be applied more or less successfully to amorphous 

 carbon and graphite, the X-ray spectrometric method is confined 

 to the diamond alone. 



Now, if we could consider the problem Irom the point of view 

 of linkages, and consequently of molecular rigidity or resistance 

 to chemical reactions, we should have a general method of attack 

 based on and supported by the chemical and physical properties 

 of the allotropic forms of carbon. 



Keeping in mind the proposed fundamental assumptions, let 

 us follow the possibilities for such a representation. 



The first class is noted by the power oj free rotation of the 

 units (single atoms or groups) constituting the carbon molecule. 

 (See fig. 5, Class I.) 



