ME. ABEL’S EESEAECHES ON GEN-COTTON. 
205 
exposure to heat, as demonstrated by a comparison of experiments 57 and 66, 41 and 70, 
56, 63 with 72, 73, and 74. 
A comparison of the general results furnished by the Waltham Abbey and Austrian 
samples might be considered to afford some foundation for the conclusion that the gun- 
cotton which contains the largest proportion of the less explosive cellulose-products is 
the most susceptible of change, but it has already been shown that this conclusion is not 
supported by comparison of the individual experiments ; and the following additional 
illustrations maybe pointed out. A sample of Waltham gun-cotton containing T83 per 
cent, of soluble matter sustained decidedly greater change than Austrian samples con- 
taining 4'5 and 5‘02 per cent., or than a Stowmarket sample containing 8 - 5 per cent. ; 
and a specimen of Austrian cotton containing 3 per cent, of soluble matter did not sustain 
less alteration, and was much more rapidly affected than one from Stowmarket containing 
11-78 per cent. Again, the specimen of Austrian gun-cotton which consisted chiefly of 
the lower nitro-products, was not so rapidly or completely changed as another Austrian 
specimen which contained only 7 f 4 per cent, of soluble matter (experiment 71), or a 
Stowmarket sample which contained but 4-3 per cent, (experiment 63). 
4. A comparison of the characters exhibited by the matters which ether and alcohol 
extracted from different samples employed in these experiments, appeared to throw much 
greater light upon the causes of their different behaviour, than the comparison of the 
proportions of soluble matter which they furnished. Reference has already been made 
(p. 201) to the matters soluble in alcohol alone, which have been discovered in small 
but variable proportions in all samples of gun-cotton hitherto examined. Both the 
quantity and character of these substances extracted from different specimens of gun- 
cotton exhibit variations, as might be anticipated, when it is remembered that they are 
derived from impurities retained by the cellulose to an extent determined by the parti- 
cular description and degree of purity of the cotton operated upon. In the Waltham 
Abbey specimens employed, the proportion of matter varied only slightly (between 0 - 72 
and 0-9 per cent.) ; yet, although the comparatively slight differences in the effects of 
heat upon the different samples were in part ascribable to variations in the proportions 
of mineral matters present, indications were obtained that the gun-cotton which resisted 
the action of heat to the greatest extent contained the smallest proportion of nitrogenized 
organic matter not derived from cellulose. The Stowmarket samples afforded much 
more decided evidence of the influence of these foreign products upon the stability of 
the gun-cotton. Two specimens (experiments 56 and 63) from which nitrous acid- 
vapours were disengaged within ten minutes of their first exposure to 100° C., and three 
others (58, 62, and 64) which, owing apparently to the influence of mineral matters, did 
not furnish acid-vapours until after five hours’ exposure, yielded extracts with ether and 
alcohol decidedly different in character from the other specimens ; a comparatively large 
proportion consisted of nitrogenized acid matter of a resinous character, soluble in 
alcohol. 
With two or three exceptions, the samples of Austrian gun-cotton exhibited decided 
mdccclxvii. 2 F 
