312 [Dec. 11, 



pendulum-apparatus, to construct a portable instrument by means of 

 which a large number of observations can be made upon a few square 

 inches of paper. They reserve the description of their instrument 

 for a future occasion. 



IV. " Notes of Researches on the Poly- Ammonias. No. XXI. 

 On Paraniline." By A. W. HOFMANN, LL.D., F.R.S. 

 Received December 2, 1862. 



In a short paper submitted to the Royal Society about a year ago *, 

 I called attention to some of the by-products which are obtained in 

 the manufacture of aniline upon a large scale, and more especially to 

 toluylene-diamine, the primary diamine of the toluyl-series. 



MM. Collin and Coblenz, aniline manufacturers at Labriche, near 

 St. Denis, Paris, to whose kindness I had been indebted for the mate- 

 rial used in these researches, immediately after their publication trans- 

 mitted to me with the utmost liberality a large quantity of basic oils 

 boiling at temperatures higher than the boiling-point of aniline, which 

 are separated from the pure aniline by rectification, and are known 

 in the language of the laboratory as queues d' aniline. The investi- 

 gation of this complex mixture has been interrupted by numerous 

 engagements arising from the International Exhibition ; and it was 

 only within the last two months that I was enabled to resume the 

 inquiry. 



This inquiry is far from being finished ; but some of the results 

 already obtained are sufficiently definite for publication. 



Submitted to distillation, the queues d' aniline begin to boil at about 

 182, considerable quantities of pure aniline passing over; the tem- 

 perature gradually rises without any indication of a fixed boiling- 

 point, until it becomes necessary to remove the thermometer ; in fact 

 the last bases are volatilized only at temperatures not very far short 

 of a red heat. By collecting separately what distils between 200 

 and 220, and again what comes over between 270 and 290, basic 

 oils are obtained from which, by appropriate treatment, very con- 

 siderable quantities, respectively, of toluylamine (toluidine) and 

 toluylene-diamine may be separated. The former of these bases more 



* Proceedings, vol. xi. p. 518. 



