3 o SCIENCE PROGRESS 



Aschan (Chem. Zeit. 1909, 33, 561), criticising Dewar's sug- 

 gestion, put forward the formula (see fig. 3). 



Fig. 2. 



Dimroth and Kerkovius (Liebig's Ann. 1913,399, 120) thought 

 a carbon molecule to consist of pentagons as well as hexagons. 



Fig. 3. 



Bragg {Proc. R. S. 191 3, A 610), studying crystalline structures 

 by means of an X-ray spectrometer, advanced a three-dimensional 

 configuration (see fig. 4) for a molecule of diamond. 



