112 On the properties and uses of Gun-cotton. 



must have observed, — that, when warm and dry, it adheres in small 

 masses to the fingers on attempting to pull it out. Such is not the 

 case with ordinary cotton. Here, then, we have a new and curious 

 property developed. Xyloidine, in all its forms, manifests highly 

 electrical properties. Professor Schonbein, by a singular process, has 

 succeeded in making from cotton a transparent paper or skin which 

 is highly electrical. He digests the gun-cotton in ether : a portion 

 is dissolved, and, by evaporation, it is obtained in a thin coherent film 

 as transparent as glass. This experiment has been tried by many 

 persons without success, even where pure washed ether was employed. 

 It would appear, however, that the addition of alcohol to the ether 

 facilitates the solution. 



Independently of its use as an explosive, gun-cotton has been 

 already employed by the pyrotechnist, and many pleasing effects are 

 produced by soaking the cotton in solutions of various salts which 

 give colour to flame, and burning it. The theatre having been dark- 

 ened, three strips of cotton prepared with a solution of strontia, 

 baryta, and soda, were burnt : each was rapidly consumed, with the 

 production of a red, green, and yellow coloured flame respectively. 



It has been stated that any kind of woody fibre may be converted, 

 by the mixture of nitric and sulphuric acids, into an explosive com- 

 pound. Saw-dust, tow, and other ligneous matters thus prepared, 

 were now produced and burnt ; but the result in these cases is to 

 leave more or less residue ; they are, therefore, far inferior to cotton- 

 wool for practical purposes. 



The Professor concluded an interesting lecture by comparing the 

 advantages and disadvantages of gun-cotton as a substitute for gun- 

 powder. Among the principal disadvantages were, the low tempera- 

 ture of explosion, — irregularity of effect, — the production of acid and 

 a large quantity of steam or aqueous vapour. He considered, how- 

 ever, that the gun-cotton had not yet had a fair trial : that in fact, the 

 discovery was too recent to allow of a proper judgment being form- 

 ed, and that its applications to practical purposes might hereafter 

 become much more extensive and useful than they were now supposed 

 to be. — London Medical Gazette. 



