1867.] 



Transformation of Aromatic Monamines, 



335 



a hyperbola, a parabola, or an ellipse, is 



Po^, ~, or . cos' Q ; 

 and whether the ellipse is referred to its major axis, becomes a circle, or is 

 referred to its minor axis, depends upon whether 



=, or >p ; 



B having any value whatever within the limits of continuity. 



It is to be observed that this method only applies on the supposition 

 that there is no abrupt discontinuity. The immersion of the gunwale, for 

 instance, would vitiate it. But in ordinary ships, experience leads to the 

 conclusion that a conic would be a very accurate representation of the locus 

 of centres of buoyancy within all reasonable limits. 



I have not waited to try the method throughout upon a specific example. 

 But every step is separately well known ; most of the steps famiharly so, 

 within my own experience. My estimate of the extra amount of work is, 

 that it would be rather less than would be involved in making an indepen- 

 dent calculation of the ordinary sheer-draught work. I shall have an im- 

 mediate opportunity of verifying this in my school ; but I wished to announce 

 the method publicly before beginning to teach it. 



II. " Transformation of the Aromatic Monamines into Acids richer in 

 Carbon.'^ By A. W. Hofmann, LL.D., F.R.S. Received 

 January 21, 1867. 



In a previous communication* to the Royal Society I have described 

 the formation of methenyldiphenyldiamine, a substance which I obtained 

 some years ago, by the action of chloroform on aniline, by means of a new 

 method, namely, by treating a mixture of phenylformamide and aniline 

 with trichloride of phosphorus. 



The continuation of these researches necessitated the preparation of 

 phenylformamide, and later also of tolylforrnamide in greater quantities. I 

 have repeatedly obtained these bodies by the action of formic ether on the 

 corresponding monamine, but in consequence of the difficulties with which 

 the preparation of formic acid in large quantities is still beset, I have of 

 late returned to the old method, viz., distillation of the oxalate of the mon- 

 amine, since I found that by employing the materials in the appropriate 

 proportions, the formation of very large quantities of the formyl com- 

 pounds may be readily accomplished. 



According to Gerhardt, the principal product of the distillation of the 

 secondary aniline-oxalate is dip heny lax amide, phenylformamide being 

 formed only as by-product. In fact, 1 molecule of oxalic acid and 2 mole- 

 cules of aniline yield almost exclusively diphenyloxamide by the separation 

 of 2 molecules of water from the secondary aniline-oxalate, thus : — 



^ 'ii 0, + 2 H In = (C„H,),In, + 2H,0 



VOL. XV. 



L 



* Proceedings of the Roval Society, vo\ xv, p. 55. 



