ME, ABEL'S EESEAKCHES ON GUN-COTTON. 30g: 



83*3 per cent.), amounted to only about 1 per cent, less than the cotton originally 

 taken ; and that when the employment of a limited quantity of acid (as in the third 

 experiment) yielded a product the weight of which represented about 2 per cent, less 

 increase than these, the cotton recovered was in this instance also only about 1 per 

 cent, below the quantity employed, the difference in the weight of the nitro-product 

 having been due only to the formation of a somewhat larger proportion of soluble gun- 

 cotton. It appears from these results, and estimating the proportion of loss which the 

 processes of conversion and reduction may involve at about 0"5 per cent., that the par- 

 ticular cotton-wool operated upon contained about 0'5 per cent, of matter foreign to 

 cellulose, which was eliminated in the course of the transformation and reproduction of 

 the latter. But, when less pure samples of cotton were converted as completely as 

 practicable into insoluble gun-cotton, and furnished results from 1"75 to 4 per cent, 

 lower than those obtained by similar treatment of the pure material, the weight of the 

 recovered cotton indicated a loss upon the original substance employed of from 4*4 to 

 6 "3 per cent., an increased loss which must be due to the larger proportion of foreign 

 matters existing in the cotton operated upon. These facts surely afford strong support 

 to the conclusion that the deficiency in weight exhibited by the products obtained from 

 ordinary cotton-wool, even after its purification with alkali, as compared with those 

 furnished under the same circumstances by purer cotton-wool, is due to the presence of 

 foreign matters in the cotton, which, though partially retained by the gun-cotton, exist 

 there in the form of products whose formation does not add, in so high a proportion, to 

 the original weight of the cotton as does the production of trinitro-cellulose. 



It follows from the above results, obtained by treatment of the ordinary cotton-wool 

 with a considerable excess of acid, that if the same cotton be treated with the limited 

 proportion of acid-mixture (10 to 14 parts by weight to 1 part of cotton) employed in 

 the ordinary course of manufacture, the products must then exhibit somewhat less 

 increase of weight (lower proportions, therefore, than 178 or 180 from 100 of cotton), 

 because, under those circumstances, the production of larger proportions of the lower 

 cellulose-products (soluble in ether and alcohol) comes into play to cause a reduction in 

 the weight of the product beyond that which is ascribable mainly to the influence of 

 the foreign matters in the cotton. 



Two quantitative operations have been conducted in the ordinary course of manu- 

 facture at Waltham Abbey, with the view of ascertaining the actual quantity of gun- 

 cotton furnished by 100 parts of cotton in the ordinary course of operating with con- 

 siderable quantities of material. 



In one experiment the cotton employed, which contained about the average quantity 

 of seed, and had as usual the peculiar colour of unbleached fibre, was submitted to the 

 ordinary purification in the bath of potassic carbonate, and was dried as usual for twenty- 

 four hours at 50° C. before immersion in acids. Its weight, when dry, was 31 lbs. 6 oz. 

 It was aftei-wards treated in all respects like an ordinary product of manufacture. The 

 weight of the air-dry gun-cotton showed an increase upon the original dry cotton of 



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