CHEMISTRY. 197 



crystals rapidly fuse when the bottle containing them is placed in 

 warm water. The original glycerine was pale brown ; the crys- 

 tals formed from it are nearly white, whilst the liquid which drains 

 away from it is dark brown. In quantity, the solid glycerine 

 looks very like a mass of sugar candy. The isolated crystals are 

 sometimes as large as a small pea; they are brilliant and highly 

 refracting ; when rubbed between the fingers they are very hard, 

 and they grate between the teeth. Their form appears to be oc- 

 tahedral, but this is difficult to ascertain accurately, owing to the 

 viscidity of the mother liquid which adheres to them. 



The crystals, separated as much as possible from the mother 

 liquor, and then fused by heat, form a clear and nearly colorless 

 liquid, slightly more viscid than usual, which, as far as I have 

 been able to ascertain, possesses all the physical and chemical 

 properties of pure glycerine. It is perfectly miscible with water 

 and alcohol. It has been especially tested for sugar and glucose 

 (common adulterants) with negative results ; lead is also absent, 

 and nitrate of silver only produces slight turbidity in its aqueous 

 solution. I believe it to be almost chemically pure anhydrous 

 glycerine. 



Some of the fused crystals have been exposed for several hours 

 to a temperature of F. without solidification taking place. The 

 only result was that the liquid became more viscid. 



The cause of the crystallization is not very clear. The most 

 probable explanation is that the vibration of the railway journey 

 across Germany, added to the intense cold to which the glycerine 

 was simultaneously subjected, enabled the particles to arrange 

 themselves in a regular form. The phenomenon then becomes 

 analogous to the crystallization of wrought iron under the influ- 

 ence of vibration, the gradual solidification of syrupy solutions of 

 organic alkaloids, and the familiar crystallization of refractory 

 platinum salts in a watch-glass by judicious friction with a stirring 

 rod. Experiments are about to be tried to see if the crystalliza- 

 tion of glycerine can be determined by exposing it to a low tem- 

 perature, and at the same time setting the particles in a state of 

 vibration. 



Should the above view of the cause of this curious phenomenon 

 be correct, we may imagine that, during the railway transit, the 

 vibratory movement was determining at the same time the crys- 

 tallization of the glycerine and the railway axles, the rapidity of 

 the action being in the inverse ratio of the viscidity of the two 

 bodies. Chemical News. 



NEW REAGENT FOR GLUCOSE. BY L. B. FRANCQUI AND L 



VANDE VYVERE. 



After noticing the several reagents used, and pointing out their 

 special inconveniences, the authors propose a solution containing 

 oxide of bismuth as being free from these defects. "We have 

 found," they say, " that hydrate of bismuth dissolves in caustic 

 potash, under the influence of certain organic bodies, such as 

 glucose, cane-sugar, dextrine, tartaric acid, etc." These solutions 



17* 



