32 PROCEEDINGS OF THE AMERICAN ACADEMY. 



very much in our preparations, and apparently disappeared entirely, 

 if during the reduction too large an excess of sulphuric acid was not 

 used. With ordinary care the free acid did not correspond to as 

 much as one tenth of the total alkali which was neutralized on boil- 

 ing, and we were unable to increase that amount beyond one fifth by 

 any modification of the mode of reduction. Our determinations fur- 

 thermore showed that each litre of distillate could contain but 1.25 grm. 

 of crotonolactone if this body had really been formed by redaction. We 

 made many fruitless attempts to isolate the crotonolactone from this 

 dilute aqueous solution, and since our main object was to establish 

 beyond question the lactone nature of the dibromcrotonolactone from 

 which it had been formed, we proceeded at last to prepare from the 

 solution a salt of the corresponding oxycrotonic acid. To the dilute 

 lactone solution we added slightly more than the required amount of 

 baric hydrate, heated the alkaline solution to boiling, precipitated 

 after the lapse of some time the slight excess of baric hydrate by car- 

 bonic dioxide, and evaporated to small volume the filtered solution. 

 We obtained in this way a somewhat brown syrupy residue, which on 

 drying yielded a hard varnish. For its purification it was dissolved 

 in a small amount of water, and alcohol added until a portion of the 

 salt had been precipitated. The filtered solution was then concen- 

 trated by evaporation, a trace of a haloid barium salt removed by the 

 cautious addition of argentic carbonate, and the clear solution evapo- 

 rated upon the water bath. After drying for some time at 100°, the 

 gummy salt became sufficiently friable to enable us to powder it, and 

 it was then thoroughly dried at 100°. A complete analysis showed 

 that this salt had the composition of a baric oxycrotonate. The sec- 

 ond determination of carbonate was made in the wet way by the 

 method of Messinger,* the first by the more usual method with potas- 

 sic dichromate in open tube. 



I. 0.19G1 grm. salt gave 0.2044 grm. C0 2 and 0.0694 grm. H 2 0. 

 II. 0.1432 grm. salt gave 0.1503 grm. C0 2 . 

 III. 0.2414 grm. salt gave 0.1655 grm. BaS0 4 . 



m 



Ba 40.44 40.33 



* Berichte d. deutsch. chem. Gesellsch., XXI. 2910. 



