HILL AND CORNELISON. — CROTONOLACTONES. 45 



0.5906 grm. air-dried salt lost over sulphuric acid 0.0492 grin. H 2 0, 

 and wheu heated at 100° it lost in addition 0.0002 grm. II 2 0. ' 



Calculated for 

 Ba(C 4 iI 3 (0C H r) )Cl0 3 ) 2 . 3 H 2 0. Found. 



H 2 8.36 8.36 



0.4814 grm. anhydrous salt gave 0.1869 BaS0 4 . 



Calculated for 

 Ba(C 4 H 3 (00 6 H 5 ,C10 3 ) 2 . Found. 



Ba 23.19 22.82 



This salt behaves toward alcohol precisely like the baric phenoxy- 

 bromoxycrotonate, and forms the same finely felted needles. 



Mucobromic Acid. 



It was shown many years ago by Hill and O. R. Jackson,* that 

 mucobromic acid could be converted into dibrommaleic acid by oxida- 

 tion with argentic oxide. When their investigation was completed 

 (1880), it was already known that phenylhydrazine reacted upon cer- 

 tain aldehydes, but experimental evidence as to the generality of the 

 reaction had not accumulated, and the importance of this body as a 

 reagent for aldehydes and ketones was not urged by E. Fischer f until 

 several years later. The characteristic behavior of hydroxylamine 

 with aldehydes and ketones was also not discovered by V. Meyer t 

 until two years later. Since the facts which we have described in 

 the preceding pages, tended to show that mucobromic acid was an 

 oxylactone and not an aldehyde acid, it was evidently necessary for us 

 to study its behavior toward phenylhydrazine and hydroxylamine. 

 Phenylhydrazine has unfortunately given us no bodies the physical 

 properties of which invited further investigation, but with hydroxyla- 

 mine we have been more successful. We have also studied the action 

 of ammonia upon ethylmucobromate, and found that mucobromamide 

 is thus formed. 



Mucobromoxime, C 4 H3Br 2 N0 3 . — Hydroxylamine acts with great 

 ease upon mucobromic acid, but we have been able to isolate the 

 oxime only when the reaction takes place in an alkaline aqueous 

 solution. The decomposition is almost instantaneous, so that after the 

 lapse of a few minutes the solution deposits upon acidification the 



* These Proceedings, XVI. 186. 



t Berichte d. deutsch. chem. Gesellsch., XVII. 572. 



t Ibid , XV. 1165, 1324, 1527, 2778, 2783; XVI. 822. 



