260 Mr. Teschemacher on Chin-Cotton. 



No. 2, 165"40 grs. of sulphate of barytes, and from No. 3, of 

 374 grs., 449-30 grs. of sulphate of barytes, making together 

 614-70 grs. ; therefore, if 100 grs. of the original acids (No. 1) 

 give 126 grs. of sulphate of barytes, 487^ grs. would give 

 614-25 grs.; they gave, as above, 614-70 grs., showing that 

 no portion of the sulphuric acid was withdrawn, but that it 

 was a portion of the ingredients of the nitric acid alone that 

 combined with the cotton. 



The quantity of soda neutralized by the acids (Nos. 2 and 3) 

 was, as just stated, 28-54 grs. ; therefore, if 32 grs. of soda 

 neutralize 54 grs. of nitric acid, 28-54 grs. of soda will give 

 48 grs. of nitric acid, the quantity of acid which disappeared, 

 or was taken up by the cotton. 



From what took place, the following may be deduced as 

 its synthetical composition: — 48 grs. of dry nitric acid, con- 

 taining 35-G6 grs. of oxygen, were decomposed by the 46-60 

 grs. of cotton, and 32-40 grs. were added to the weight of the 

 cotton. It is probable that the mixed acids combined with a 

 portion of the constituent water of the cotton, which was 

 replaced by oxygen and nitrogen, in the proportions of nitric 

 acid, as there was no appearance of the evolution of either 

 nitrogen or oxygen in the formation of the gun-cotton. 

 Its synthetical composition would stand thus : — 



46-60 grs. of cotton deprived of 



15 "60 water, give 



31-00 cotton without constitutional water, combined with 



48-00 oxygen and nitrogen derived from the mixed acids. 



79-00 the weight of gun-cotton produced, equal to 



39-25 parts cotton, 



6O-75 ... oxygen and nitrogen (nitric acid) 

 in 100-00 parts. 



From these experiments we arrive at the following conclu- 

 sions regarding the formation of this substance : — That as it 

 requires 48 grs. of nitric acid, or its equivalent 90*66 grs. of 

 saltpetre, to form 79 grs. of gun-cotton, it will require 60*75 

 grs. of nitric acid, or its equivalent 1 14-76 grs. of saltpetre, to 

 form 100 grs. of gun-cotton ; and according to the same calcu- 

 lation, it will require 97*76 grs. of nitrate of soda for the same 

 purpose. 



Taking into consideration the original cost of the cotton, 

 the expensive manipulation of the conversion of the nitre into 

 nitric acid, and the additional weight of nitre required to 

 produce the same weight of gun-cotton, it is evident that the 

 latter substance must be more expensive than gunpowder, 

 taking weight for weight of each. How far, however, gun- 



