502 Scientific Intelligence. 



poses it slowly, boiling water more rapidly, and alkalies very 

 readily, with production of ammonia. A better yield is obtained 

 by passing nitrogen over a mixture of aluminum and dry calcium 

 hydrate. — J. Ghem. Soc, lxxiv, ii, 377, August, 1898. G. F. B. 



6. On Enantiomorphism. — As is well known, enantiomorphous 

 substances are divisible into two classes, intermolecular and intra- 

 molecular ; i. e., those in which this property is determined by 

 the arrangement of the molecules, and those in which it is deter- 

 mined by their structure. The first class, to which belong quartz 

 and sodium chlorate, are not optically active in solution, though 

 their crystals rotate the plane of polarization. The second class, 

 to which belong all compounds containing an asymmetric carbon 

 atom, are active in the amorphous or liquid state as well as when 

 crystallized. But while the latter must invariably give crystals 

 which are either right-handed or left-handed, there appears no 

 reason why the former should give crystals of the one sort in 

 preference to those of the other. Kipping and Pope have 

 studied the crystals of sodium chlorate deposited from pure 

 aqueous solutions to ascertain whether the ratio of dextro- to laevo- 

 sodium chlorate is in fact unity. About 200 cc of a saturated solu- 

 tion of this salt was placed in a shallow glass crystallizing dish 

 and allowed to evaporate spontaneously. Each crystal developed 

 apart from its fellows as a right-angled prism ; and when they 

 were about 5 mm on a side, they were removed from the liquid and 

 the sign of the circular polarization was determined by examina- 

 tion in a polarizing microscope with an inch objective. If the 

 analyzer had to be turned to the right to give extinction, the crys- 

 tal was dextro-rotatory ; and vice versa. In only two cases out 

 of 46 crystallizations were equal numbers of dextro- and laevo- 

 rotatory crystals deposited. But the mean percentage value in 

 all the 46 experiments gave 50-83 of dextro crystals ; while the 

 weighted mean, in which allowance is made for the total number 

 of crystals obtained, gave 50*08, with a probable error of 0*11. 

 It appears therefore that on allowing sodium chlorate to crystal- 

 lize spontaneously from pure aqueous solutions, equal numbers of 

 the enantiomorphously related crystals, on the average, are depos- 

 ited. The authors then took up the question whether, if the 

 crystallizing sodium chlorate solution contained an enantiomorph- 

 ous substance of the second class, i. e., containing an asymmetric 

 carbon atom, such as dextroglucose for example, there would be 

 the same tendency, aside from the solubility, for dextro- as for 

 hevo-sodium chlorate to crystallize. For this purpose they used 

 solutions containing dextrose, mannitol and dulcitol and found 

 the weighted means to be 31-75, 40*55 and 51*27 respectively. 

 Whence they conclude that on crystallizing a substance which is 

 not enantiomorphous in the amorphous state in presence of one 

 which is so, the average ratio of the crystals of each sort depos- 

 ited may be made to differ from unity. — J. Chem. Soc, Ixxiii, 

 606-617, August, 1898. g. f. b. 



