D. CHEMISTRY AND METALLURGY. 79 



the objects being readily snapped by a very slight pressure. 

 It was found, however, that by gentle hammering, or rolling, 

 the brittle mass could be easily restored to its original mal- 

 leable condition, while its density gradually rose from 9.06 

 to 10.2. From this it would appear that the change is mo- 

 lecular, and not chemical, the extreme portions alone being 

 modified. 21.4, July, 1871,498. 



DAMBOSE, AN INGREDIENT OF BORNEO CAOUTCHOUC. 



M. A. Girard, in a late communication to the Academy of 

 Sciences of Paris, presents a notice of a new volatile and sac- 

 charine principle discovered some time ago by him in the 

 caoutchouc of Borneo, and which is remarkable for its de- 

 composition in the presence of hydriodic acid. This, wheu 

 heated in a closed vessel to a certain temperature w T ith an ex- 

 cess of the acid, separated into a methyl-hydriodic ether, and 

 a new substance, likewise saccharine, crystalline, and of great 

 stability, having the composition of dried glucose, and hav- 

 ing much analogy with inosite. This substance he names 

 dambose. 3 J5, xvn., August 24,1871, 337. 



CHARACTERS OP PURE GLYCERINE. 



According to Roller, among the characteristics of pure 

 glycerine, as compared with an impure article, are the fol- 

 lowing :' Pure glycerine has a neutral reaction, and on. evap- 

 oration in a porcelain dish leaves only a very slight carbona- 

 ceous crust, while the impure has a much greater percentage 

 of coaly matter. The pure article does not become brown 

 when treated, drop by drop, with concentrated sulphuric acid, 

 even after several hours ; the impure becomes brown even 

 when but slightly adulterated. Pure glycerine, treated with 

 pure nitric acid and a solution of nitrate of silver, does not 

 become cloudy, while the impure exhibits a decidedly milky 

 appearance. Sometimes the impure article becomes black- 

 ened with the sulphide of ammonium. Oxalate of ammonia 

 produces a black clouding; lime-water sometimes causes a 

 milky discoloration. Pure glycerine, however, constantly re- 

 mains perfectly uncolored, and clear as water, the impure be- 

 coming colored to a greater or less extent. If a few drops 

 are rubbed between the fingers, pure glycerine causes no fat- 

 ty smell ; the contrary is the case with the impure, especially 



