July 7, 1922] 



SCIENCE 



29 



about p„ = 8, at all concentrations; the curves 

 show a "shoulder" near the isoelectric point 

 (Pg = 4.8) but no definite masimum or minimum. 

 On adding aluminum salts, to give as low as .01 

 per cent. Al^O, on dry gelatin, the course of the 

 curve was greatly altered, a secondary maximum 

 being produced at Pj^ = 5, and the maximum on 

 the alkaline side displaced. 



The formation of inorganic jellies: general 

 theory: Harbt B. Weiser. Factors that influence 

 the formation of jellies in general are: A jelly 

 may be expected to form if a suitable amount of 

 a highly hydrous substance is gotten into colloidal 

 solution and allowed to precipitate at a suitable 

 rate without stirring. If the concentration of the 

 hydrous substance is too low, no jelly or only a 

 very soft jelly can result. If the precipitation 

 from colloidal solution is too rapid, contraction 

 is likely to occur with the formation of a gel- 

 atinous precipitate instead of a jelly; if too slow, 

 the particles are likely to grow and settle out in a 

 granular or sandy mass. The effect of the pres- 

 ence of salts on jelly formation is determined by 

 the agglomerating and stabilizing action of ions, 

 in so far as these affect the rate of precipitation. 



The adsorption and orientation of inolecides of 

 dibasic organic acids and their ethereal salts in 

 liquid-vapor interfaces: H. H. King and E. W. 

 Wampleb. Adsorption values are given for oxalic, 

 malonic, succinic, fumaric, maleic and d tartaric 

 acids and the di-ethyl esters of all the above acids 

 with the exception of oxalic and maleic. The 

 values were calculated using Gibbs' equation. 

 Hydroxyl groups and double bonded carbons 

 increase the surface tension, as is shown by the 

 fact that d tartaric acid has the highest surface 

 tension, and in order maleic malic to succinic, 

 which has the lowest. The higher surface tension 

 of the acids as compared with the esters is due to 

 their polarity. The influence of the polar groups 

 in the esters is similar. The esters are adsorbed 

 more than the acids due to the replacement of the 

 polar groups with the insoluble ethyl group. The 

 molecules are orientated so that the polar groups 

 are in the liquid leaving the carbon chains in the 

 surface. Tartaric acid is negatively adsorbed, 

 the surface tension of an 8 M solution being 

 74.125 and a .125 M solution being practically 

 that of water. 



The atomic weight of lanthanum: B. S. Hop- 

 kins and F. H. Deiggs. The lanthanum from 

 182 kg. of cerium group double sulphates was 

 purified by fractional crystallization of the double 

 magnesium nitrates until free from neodymium 

 followed by fractional crystallization of the 



double ammonium nitrates. The are and absorp- 

 tion spectra of the insoluble end of this series 

 showed it to be free from all other rare earths. 

 The material was further purified by eight alter- 

 nate precipitations with ammonia and oxalic acid. 

 The pure oxide was converted to the chloride in a 

 quartz flask with pure dry HCl and weighed. A 

 nearly equivalent amount of pure silver was 

 weighed out, dissolved in HNO and added to the 

 solution of LaCl . The deficiency of silver or 

 chloride was added from a standard solution of 

 AgNO and NaCl. Equivalence was tested for 

 with the nephalometer. From tlie ration, 

 LaCl : 3Ag, the atomic weight of La was calcu- 

 lated. The average of five determinations was 

 138.91. 



Thermo-regulator : E. B. Starkey and Neil E. 

 Gordon. A thermo-regulator, designed to meet 

 the needs of the individual student in physical 

 chemistry. It has an accuracy to .05° C, and 

 does not require a relay or battery. Furthermore, 

 the point of contact is enveloped in an atmos- 

 phere of inert gas, and hence there is no oxidation 

 at the point of contact. 



The concentrations of allcali halide solutions of 

 the order of 0.0001 N most favorable to adsorp- 

 tion hy barium sulphate: Jack P. Montgomery. 

 Bach halide was used in concentrations progress- 

 ing from 0.00004 N to 0.001 N in a series of 50 

 ce cylinders each containing 0.01546 gram barium 

 sulphate. The upper half of each solution was 

 withdrawn for titration with 0.004 N silver 

 nitrate. There was a regular progression of the 

 volume of silver nitrate required until a certain 

 concentration of the halide was reached, at which 

 concentration less than the expected volume was 

 required. Having passed this concentration the 

 progression became regular as before. Plotting 

 the halide adsorbed against the concentration, the 

 curves are regular except for a dip at the point 

 showing the most favorable concentration. Favor- 

 able concentrations are LiCl, 0.00088 N; NaCl, 

 0.00072 N; KCl, 0.00034 N; EbCl, 0.00014 N; 

 LiBr, 0.00068 N; NaBr, 0.00056 N; KBr, 0.00016 

 N; Lil, 0.0001 (?). 



The transposition of insoluble oxalates by 

 sodium carbonate solution: L. J. Cubtman and 

 D. Hart. "Working under the most favorable con- 

 ditions for the transposition of calcium oxalate by 

 sodium carbonate solution, it was found that 91 

 per cent, was transposed. With the oxalates of 

 barium, strontium, ferric and ferrous iron, alum- 

 inum, nickel, cobalt, manganese, zinc, bismuth, 

 copper and stannous tin, a transposition of 98 to 

 100 per cent, was obtained. The oxalates of cal- 



