IMPROVEMENTS IN GUN-COTTON. 
273 
trust that this reaction may prove useful as a means for the detection of an adulteration 
which, I am sorry to say, numerous analyses have shown me is practised to some extent 
in this city.* 
IMPROVEMENTS IN GUN-COTTON. 
(Report by ilie Committee appointed to investigate some improvements in Gun-cotton. 
Read before the British Association. The Chemical portion by Dr. Gladstone.) 
Since the invention of gun-cotton by Professor Schbnbein, the thoughts of many have 
been directed to its application to warlike purposes. Many trials and experiments have 
been made, especially by the French; but such serious difficulties presented themselves 
that the idea seems abandoned in every country but one, Austria. From time to time 
accounts reached England of its partial adoption in the Austrian service, though no 
explanation was afforded of the mode in which the difficulties had been overcome, or the 
extent to which the attempts had been successful. The Committee, however, have been 
put in possession of the fullest information from two sources—Professor Abel, chemist to 
the War Department, and Baron W. von Lenk, Major-General in the Austrian Artillery, 
the inventor of the system. Professor Abel, by permission of the authorities, communi¬ 
cated to the Committee the information given by the Austrian Government to our Go¬ 
vernment, and also the results of his own elaborate experiments. General von Lenk, on 
the invitation of the Committee, by permission of the Austrian Government, paid a visit 
to this country, to give every information in his power on the subject, and brought over 
drawings and samples from the Imperial factory. The following is a summary of the 
more important points:—As to the chemical nature of the material, Von Lenk’s gun¬ 
cotton differs from the gun-cotton generally made, in its complete conversion into a uni¬ 
form chemical compound. It is well known to chemists that when cotton is treated 
with mixtures of strong nitric and sulphuric acids, compounds may be obtained varying 
considerably in composition, though they all contain elements of the nitric acid and are 
all explosive. The most complete combination (or product of substitution) is that de¬ 
scribed by Mr. Hadow as C 3R H 21 (9NO 4 )O 30 , which is identical with that termed by the 
Austrian chemists Trinitrocellulose, C 12 H 7 (3NO 4 )O 10 . This is of no use whatever for the 
making of collodion ; but it is Von Leuk’s gun-cotton, and he secures its production by 
several precautions, of which the most important are the cleansing and perfect desiccation 
of the cotton as a preliminary to its immersion in the acids,—the employment of the 
strongest acids attainable in commerce,—the steeping of the cotton in afresh strong mix¬ 
ture of the acids after its first immersion and consequent imperfect conversion into gun¬ 
cotton,—the continuance of this steeping for forty-eight hours. Equally necessary is 
the thorough purification of the gun-cotton so produced from every trace of free acid. 
This is secured exclusively by its being washed in a stream of water for several weeks. 
These prolonged processes are absolutely necessary. It seems mainly from the want of 
these precautions that the French were not successful. From the evidence before the 
Committee it appears that this nitro compound, when thoroughly free from acid, is not 
liable to some of the objections which have been urged against that compound usually 
experimented upon as gun-cotton. It seems to have a marked advantage in stability 
over all other forms of gun-cotton that have been proposed. It has been kept unaltered 
for fifteen years; it does not become ignited till raised to a temperature of 13G° C. (277° 
Falir.) ; it is but slightly hygroscopic, and when exploded in a confined space, is almost 
entirely free from ash. There is one part of the process not yet alluded to, and the value 
of which is more open to doubt,—the treatment of the gun-cotton with a solution of sili¬ 
cate of potash, commonly called water-glass. Prefessor Abel and the Austrian chemists 
think lightly of it; but Von Lenk considers that the amount of silica set free on the 
cotton by the carbonic acid of the atmosphere is really of service in retarding the com¬ 
bustion. He adds, that some of the gun-cotton made at the Imperial factory has not 
been silicated at all, and some imperfectly ; but when the process has been thoroughly 
performed, be finds that the gun-cotton has increased permanently about 3 per cent, in 
weight. Much apprehension has been felt about the effect of the gases produced by the 
* I may mention that “cleaned spirit” is capable of reacting with the mercurial salt in a 
manner precisely similar to the ordinary “'methylated spirit.” 
