TRAI5SACTI0NS OF SECTION B. 647 



MONDAY, SEPTEMBER 5. 

 The following Papers were read : — 



1. The Relation of Geometrical Structure to Chemical Properties. 

 By Professor Wislicenus. 



Note on Valency, especially as defined hy Helmlioltz. 

 By Professor Aemsteong, F.B.S. 



3. The Solubility of Isomeric Organic Compounds. By Professor 

 Carnelley, D.Sc, and Dr. A. Thomsok. 



1. For any series of isomeric, organic cotnpounds the order of solubility is the 

 same as the order of fusibility, i.e. the most fusible coinpouud is also the most 

 soluble. (Cf. Carnelley, ' Phil. Mag.' (5) 13, 180 ; also Tilden, ' Journ. Chem. 

 Soc.' 45, 266). 



This is shown to hold true in a very large number of cases, whilst there are very 

 few exceptions, and those of a doubtful character. 



2. Tlie order of solubility of two or more isomeric compounds is independent oj 

 the nature of the solvent. This has been experimentally proved, more particularly 

 in the case of meta- and para-nitraniliue, the solubility of each oi which in thirteen 

 different solvents has bten determined ; also by a considerable number of cases 

 taken from literature. 



3. The ratio of the solubilities of two isomers in a given .lolvent is constant, and 

 is therefore independent of the nature of the solvent. So that — 



Solubility of A in any solvent ^ constant. 

 Solubilif y of B in the same solvent 



This has been proved for meta- and para-nitraniline in respect of thirteen different 

 and very varied solvents. 



4. The Melting Points of Organic Compounds in relation to their Chemical 

 Constitution. Part I. — Influence of Orientation in Aromatic Compounds. 

 By Professor Carnelley, D.Sc. 



For any series of isomeric compounds of benzene the symmetry of the orienta- 

 tion of the side chains has a very marked influence on the melting-point, in such a 

 way that, cceteris paribus, the most symmetrical orientation gives the highest melting 

 point. Thus, of 1,120 cases in which the law can be applied, 890 agree with the 

 rule, though there is a high a priori probability against their doing so, varying from 

 2 : 1 to 1 5 : 1 in different cases. 



Of the exceptions considerably more than one-half are of a doubtful character, 

 whilst five-sixths of them depend on one authority only. 



Further, as regards all benzene isomers the order of infusibility, much more fre- 

 quently than not, follows the order of symmetry of orientation, though the h priori 

 probability against their doing so is a very high one. 



5. Alcohol and Water Comhinations. By Professor Mendeleef. 



6. On the Constitution of Atropine.'^ By Professor Ladenburg. 



By the researches of Kraut and Lossen we have learnt that the alkaloid of 

 the belladonna atropine Cj^HojNOg is decomposed by hydrochloric acid or hydrate 

 of baryta in tropine CgHj^NO and tropic acid OgHjiPg. 



' Ann. Chem. 217, 74 ; Her. IG, 1408 ; and Ecr. 20, 1C47. 



