680 



SCIENCE 



[Vol. LV, No. 1434 



author has shown that the structure of graphite, 

 as determined by X-ray analysis,^ is exactly 

 what would be obtained if it were built of 

 layers of benzene hexagons of the type just 

 described, the carbon-hydrogen bonds of the 

 benzene molecules being replaced by carbon- 

 carbon bonds between the layers. Such an 

 arrangement not only accounts for the sym- 

 metry of the substance and for the observed 

 spectra, but also for its known chemical and 

 physical properties. 



There are quite a number of aromatic com- 

 pounds, including benzene itself, in crystals of 

 which, according to the author's conjugation 

 theory, we might expect the molecules to be in 

 layers of much the same type as the layers in 

 graphite. Assuming this to be the case, if the 

 densities, axial ratios and axial angles are 

 known, the dimensions of the hexagon in these 

 crystals can be calculated. This has been done 

 for a considerable number of substances, and 

 in every case in which large distortions would 

 not be expected, due to substituted groups, the 

 dimensions of the hexagon are very close to the 

 corresponding dimensions in graphite. If this 

 result were obtained for one or two crystals, it 

 might be considered merely a coincidence, but 

 it is found to be general; the dimensions are 

 found to correspond best where least distortion 

 would be expected; and the axial ratios and 

 angles, and the crystal form, symmetry and 

 cleavage, as well as the actual distances, are 

 found to conform to the structures assumed. 

 ■Hence this structure for the benzene nucleus 

 must be considered proved. 



This method of proof was reported on by 

 the author in a paper presented at the twenty- 

 fourth special meeting of the California Sec- 

 tion of the American Chemical Society, held in 

 conjunction with the annual meeting of the 

 Pacific Division of the American Association 

 for the Advancement of Science, at Berkeley, 

 California, on August 5, 1921, at which time 

 the structures of quinol, pyroeateehin and 



8 Debye and Sdierrer, Phys. Zeit., 17: 277 

 (1916); 18: 291 (1917); Hull, Phys. Bev., 10: 

 661 (1917). 



The author 's interpretation of the experimental 

 results is a compromise between that of Hull and 

 that of Debve and Scherrer. 



triphenyl carbiaol were used as examples. The 

 densit3' of solid benzene was not then to be 

 found in the literature. This is now obtainable, 

 and from it and the axial ratios, by assuming 

 close packing of the molecules in each layer, 

 the hexagon dimensions can be computed. They 

 again cheek with those in graphite. 



A paper is now being prepared in which the 

 method of proof and its application to a large 

 niunber of aromatic compounds will be given 

 in detail. 



Maurice L. Huggins 

 Univebsitt of California, 

 Berkeley, Calif., 



THE AMERICAN ASSOCIATION FOR 



THE ADVANCEMENT OF SCIENCE 

 MEETING OF THE EXECUTIVE COMMITTEE 

 OF THE COUNCIL 

 The spring meeting of the executive com- 

 mittee was held in the board room of the 

 Cosmos Club, Washington, D. C, on April 23. 

 It was called to order at 4 :10, with Dr. Simon 

 Flexner in the chair and with all members 

 present, and it adjourned at 11 :30, a recess of 

 an hour and a half having been taken for 

 dinner. The main items considered are shown 

 below. 



(1) Minutes of the last meeting (December 

 31, 1922), and of two actions taken by mail 

 ballot in the interim were approved. These 

 interim actions were (1) the formal vote to 

 authorize the summer meeting with the Paeifie 

 Division, which is to occur on June 22-24, at 

 Salt Lake City, and (2) the election of Dr. 

 J. McK. Cattell to succeed himself as a member 

 of the Board of Science Service. 



(2) The permanent secretary presented a 

 report on the affairs of the association for the 

 half-year ending March 31. A summary of 

 that z'eport is appended to the report of this 

 meeting. 



(3) It was voted that all members of the 

 American Medical Association who are not 

 already members of the American Association 

 for the Advancement of Science may become 

 members of this association without the pay- 

 ment of the usual entrance fee ($5). The 

 A. A. A. S. is unable each year to invite all 



