Studies with Vibrating Mechanical Models I. Benzene, Toluene and the Phenyl Halides

By continuing the work of Kettering, Shutts and Andrews, mechanical models have been constructed for the series of compounds: $${\mathrm{C}}_6{\mathrm{H}}_6\mathrm{,\hspace{0.17em}\hspace{0.17em}}{\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{CH}}_3\mathrm{,\hspace{0.17em}\hspace{0.17em}}{\mathrm{C}}_6{\mathrm{H}}_5\mathrm{Cl}\mathrm{,\hspace{0.17em}\hspace{0.17em}}{\mathrm{C}}_6{\mathrm{H}}_5\mathrm{Br}\mathrm{,\hspace{0.17em}\hspace{0.17em}}{\mathrm{C}}_6{\mathrm{H}}_5\mathrm{I}.$$ The mechanical frequencies of the simpler types of motion show some correlation with the spectral lines, especially in the shifts of frequency in passing down the series of compounds. The types of motion observed are in fair accord with the types deduced with the aid of group theory.