On Salt Solutions and Attached Water. 35 



nitrogen, as conjectured in (3), giving stability to the 

 molecule, and preventing the oxidation of the methyl-groups 

 to carboxyl. 



7. On treatment with sodium, these bases are polymerized, 

 no hydrogen being evolved by the action of the sodium on 

 the base. An addition-product is consequently formed, 

 probably by two atoms of sodium being taken up by each mole- 

 cule of base ; on coming into contact with a fresh molecule 

 of base, the sodium leaves the first molecule, which has thereby 

 its affinities free for union with another similarly placed. I 

 am very doubtful if any compound of picoline and sodium is 

 formed. Certainly sodium does not combine with dipicoline ; 

 for that base can be freed from water by heating it to a high 

 temperature with metallic sodium. 



8. In conclusion, I would remark the analogy between the 

 furfurol and pyridine groups. That they are closely related 

 appears very probable. An attempt to effect the conversion 

 of furfurol, C 5 H 4 2 , into pyridine through the following- 

 series of reactions, failed owing to the instability of furfuryl 

 chloride. 



C.H.O,, C 5 H 6 2 , C 5 H 5 OCI, C 5 H 5 ONS 2 , C 5 H 5 N. 



Furfurol. Furfuryl Furfuryl Furfuryl amine Pyridine, 



alcohol. chloride (unknown). 



(unknown). 



The furfurol group, from its unstable nature, is probably 

 analogous to the higher homologues of acetylene, and is best 

 represented by an open chain ; whereas the pyridine group, 

 from its stability, and from the number of isomeric deriva- 

 tives obtained from it, is, like benzol, best pictured by a closed 

 chain. 



In closing this research, I have to express my deep indebt- 

 edness to Professor Ferguson for placing at my disposal the 

 material which belonged to the late Professor Anderson. 



IY. On Salt Solutions and Attached Water. 

 By Frederick Guthrie*. 



[Continued from vol. ii. p. 225.] 



VI. 



Further Examples of Cryohydrates and Cryogens. 



§ 167. J-JYDRATE of Barium. — On cooling a saturated 



solution of this salt, the well-known recognizable 



crystals are continually deposited until the temperature reaches 



* Communicated by the Physical Society. 

 *D2 



