110 



CHEMISTRY. 



Actual immersion in water is not necessary 

 for the most perfect preservation of gun-cotton ; 

 the material, if only damp to the touch, sus- 

 tains not the smallest change, even if closely 

 packed in large quantities. The organic im- 

 purities which doubtless give rise to the very 

 slight development of acid observed when gun- 

 cotton is closely packed in the dry condition 

 appear to be equally protected by the water ; 

 for damp or wet gun-cotton which has been 

 preserved for three years has not exhibited the 

 faintest acidity. If the proper proportion of 

 sodic carbonate be dissolved in the water with 

 which the gun-cotton is originally saturated for 

 the purpose of obtaining it in this non-explosive 

 form, the material when it is dried for conver- 

 sion into cartridges, or for employment in other 

 ways, will contain the alkaline matter required 

 for its safe storage and use in the dry condition 

 of all climates. 



Wilhelm and Ernst Fehleisen have recently 

 found an explosive compound which they call 

 haloxylin. It cleaves rather than blows into 

 atoms an important quality, especially when 

 it is employed in coal-mines. It does not ignite 

 spontaneously, nor is it set on fire by friction 

 or percussion. Its combustion gives rise to no 

 opaque or suffocating gases, which makes it 

 very valuable in operations of tunnelling. It 

 has one disadvantage : weight for weight it is 

 twice as bulky as gunpowder ; but this is in 

 a great measure compensated for by the fact 

 that it is one-half more powerful. Haloxylin is 

 formed by thoroughly mixing nine parts, by 

 weight, sawdust, obtained from a light and 

 non-resinous wood, or wood from which the 

 resin has been extracted, from three to five 

 parts charcoal, and forty-five parts saltpetre : 

 and, if required to be quick, one part ferrocy- 

 anide of potassium the mixture being moist- 

 ened with one quart of water to every hundred 

 weight. It is granulated by stamping or crush- 

 ing, and the grains may be polished in the ordi- 

 nary way ; this, however, merely improves the 

 appearance of the compound, without increasing 

 its explosive power. 



Experiments made on the effects produced 

 by nitrate or chlorate of potash on glue have led 

 to the discovery of a new and extremely cheap 

 explosive compound, which may be employed 

 with advantage in conjunction with ordinary 

 gunpowder. The compound may be obtained by 

 two methods. One is to wash two parts glue 

 with cold water, then heat the glue moderately 

 with a small quantity of nitric acid, evaporate, 

 again mix with water, free from acid by car- 

 bonate of baryta, not in excess ; again evapo- 

 rate to dryness, mix with one part sulphur, 

 then with water, and then with six parts 

 nitrate of potash. The other method is to melt 

 the glue in warm water, and add to it half the 

 nitrate of potash, and then the sulphur, after 

 which the mixture is heated until it assumes a 

 uniform appearance, when the rest of the 

 nitrate is added. The compound obtained 

 by either of these methods is neither deli- 



quescent nor hydroscopic, but, being made 

 with nitrate instead of chlorate, unless mixed 

 with ordinary gunpowder, it burns slowly and 

 without explosion. It produces the best ex- 

 plosive effects when mixed with five parts gun- 

 powder. 



New Process for Obtaining Oxygen or Chlo- 

 rine. M. Mallet has recently discovered a pro- 

 cess for obtaining oxygen or chlorine, founded 

 on the properties of protochloride of copper 

 (CuCl.), of absorbing oxygen from the atmos- 

 phere and becoming oxychloride (CuClCuO.), 

 which, when heated to a temperature of 400 

 0., gives up the oxygen and again becomes 

 protochloride. The process is capable of repe- 

 tition without loss any number of times with 

 the same protochloride. The latter, to prevent 

 igneous fusion, is mixed with some inert sub- 

 stance, such as sand ; and on the large scale the 

 retorts should be capable of rotation, for the 

 purpose, during the separation and reabsorption 

 of the oxygen (which may be effected in the 

 same vessel), of equalizing the temperature, 

 and keeping the materials well mixed. On the 

 small scale, the process may be carried on in 

 a glass retort, from which the protochloride is 

 removed when oxygen is to be reabsorbed. 

 Reabsorption takes place rapidly with a suitable 

 current of air, especially if the materials are 

 slightly moistened. The same materials and 

 apparatus may be used in obtaining chlorine. 

 For this purpose hydrochloric acid is added to 

 the perchloride after it has absorbed oxygen. 

 The gaseous chlorine disengaged in soda- works 

 may be used on the large scale. Bichloride 

 of copper is formed, and from that the chlorine 

 is obtained. 



Oxygen is also now obtained very economi- 

 cally by the decomposition of sulphuric acid, 

 effected by means of heat and an apparatus de- 

 vised for the purpose. The acid is decomposed 

 into oxygen and sulphurous acid, and the latter 

 is removed by liquefaction produced by pres- 

 sure. The sulphuric acid employed is not 

 wasted, it is merely the vehicle for obtaining 

 oxygen from the atmosphere, and may, there- 

 fore, be employed over and over again, the 

 sulphurous acid, after each operation, being 

 changed back to sulphuric acid in the usual 

 way. A kilogramme of sulphuric acid at 60 

 affords a cubic metre of oxygen. (Intellectual 

 Observer, April.) 



The Cyanides. Professor A. W. Hofmann 

 has communicated to the French Academy of 

 Science a memoir of a class of cyanides 

 isomeric with the so-called nitriles but pos- 

 sessing very different properties. When an 

 alcoholic solution of ethylamine and chloro- 

 form is gradually poured into a retort contain- 

 ing caustic potash a violent reaction ensues, 

 and among the products of the distillation 

 cyanide of ethyl is formed as a liquid possess- 

 ing an intolerably penetrating odor. The 

 author had not carefully studied this body, but 

 he gave a detailed account of the cyanide of 

 amyl, which is formed by a similar reaction. 



