CHEMISTRY. 523 



ily soluble in glacial acetic acid; dissolved in strong snlphnric acid it 

 blackens by charring ; it is readily soluble in alkalies and alkaline car- 

 bonates. It forms two potassium salts K2 C14 H12 O4 and K Cu H^ O4, 

 as well as calcium, zinc and barium salts, the last named being insoluble. 

 By a study of the esters of curcumin the authors definitely establish Cu 

 H]4 O4 as the true formula. The results of incomplete oxidation are 

 most interesting ; by treating an aqueous alkaline solution with potas- 

 sium permanganate, not in excess, a strong smell of vanilla was observed. 

 Further treatment effected the separation of an oil, gradually solidifying 

 in circular groups of radiating needles, and having a strong odor of 

 vanilla. By sublimation and purification of this product, white needles 

 of vanillin, melting at 78° C, were obtained. The yield was very small. 

 The authors also show that diethylcurcumin yields by oxidation ethyl- 

 vanillic acid. [Am. Cliem. Jonrn., iv, p. 77.) 



Urea, its Synthesis and its Estimation. — Fenton has succeeded in trans- 

 forming urea into cyanamide; the dehydration was effected by means 

 of sodium in accordance with the reaction : 



2 CON2 H4 + 2 Ka = 2 CN2 H2 + 2 Na OH -f Hg 



Prof.W. G. Mixter has succeeded in forming urea by the reaction of am- 

 monia on carbonic anhydride at a red heat. The urea forms slowly, 2 

 to 3 decigrams per hour, and collects in fine crystals in the cooler parts 

 of the tube through which the gases are conducted. He regards the 

 formation of urea, as preceded hy that of cyanic acid, thus : CO2 + NH3 

 = HCNO -f H2 O. The cyanic acid probably unites with ammonia in 

 the cooler part of the tube to form urea. {Am. Chem. J., rv, p.. 35.) 



J. R. Duggan described a modification of Knop's process of estimating 

 urea by the amount of nitrogen evolved on the addition of an alkaline 

 hypobromite. His method consists in mixing the urea and caustic soda 

 solutions first and then adding the bromine. He employs a caustic soda 

 solution made by dissolving 20 grms. of sodium hydrate in 100 c. c, of 

 water ; and with each 20 c. c. of this he uses 1 c. c. of bromine. The re- 

 sults are satisfactory. The weight of nitrogen multiplied by 2.143 gives 

 the amount of urea. [Ayn. Chem. J., iv, p. 47.) 



Dr. Theodore G. Wormly has also investigated the above method of 

 determining urea and finds that only under the following conditions is 

 the whole of the nitrogen uniformly set free : 1st. The reagent (hypo- 

 bromite) should be freshly prepared ; 2d. The urea solution should be 

 wholly added to the reagent ; 3d. The amount of urea operated ui^on 

 should not exceed 1 part to about 1,200 parts of the diluted reagent; 

 4th. When comparatively large amounts of urea are present the sur- 

 rounding temperature should not be less than about 20° C. (68° Fah.). 

 {Chem. Netvs, xlv, p. 27.1 



Acrolein Urea. — Hugo Schiff has described under the name acryldiu- 

 reide, a body resulting from the union of two molecules of urea and one 

 of acroleine : Prof. A. R. Leeds has obtained a body having the same 



