544 



other. When p=q, the corresponding pair will sometimes be iden- 

 tical figures, as to the number, rank, and arrangement of faces and 

 summits ; and at other times, as is always the case if p be not equal 

 to q, the two figures will differ. When they differ they may be 

 called a sympolar pair, both being heteropolar; when they form one and 

 the same figure it may be styled an autopolar polyhedron. An elegant 

 way of representing a sympolar pair is deduced from the two follow- 

 ing theorems : 



A. The q summits of a q-acron are the angles of a closed polygon 

 of q sides, all edges of the q-acron. 



B. A closed polygon of p sides can be traced on the p faces of 

 every p-edron, having a side in every face, and passing through no 

 summit. 



December 13, 1855. 

 Col. SABINE, R.A., Treas. and V.P., in the Chair. 



It was announced that Mrs. Young, widow of Thomas Young, 

 M.D., For. Sec. R.S., had presented to the Society a volume of MS. 

 letters addressed to her husband by MM. Arago, Fresnel, Poisson, 

 La Place, A. Humboldt, Berzelius, Biot, Bessel, and Dr. Wollaston. 



The following communications were read : 



I. "On the Action of Sulphuric Acid on the Nitriles and on 

 the Amides." By G. B. BUCKTON and A. W. HOFMANN, 

 Ph.D., F.R.S. Communicated by Dr. HOFMANN. Re- 

 ceived December 1, 1855. 



Although the identity of the nitriles with the hydrocyanic ethers 

 has been established by the experiments of M. Dumas, who obtained 

 them by the action of anhydrous phosphoric acid upon certain am- 

 moniacal salts, chemists have hitherto in vain sought for a method 

 by which a passage might be effected from the nitriles to the general 

 alcohol derivatives. 



Our attention has been directed likewise to the same subject, but 



