BKISTOL NATURALISTS SOCIETY. 
From the Bristol Daily Post of February 6th, 1865. 
The usual monthly meeting was held on Thursday evening 
last, at the Philosophical Institution, under the presidency 
of Mr. W. Sanders. There was a good attendance of mem- 
bers and visitors. Mr. A. Leipner, the hon. secretary, 
announced that Messrs. J. Gould, J. J, Ransom, H. Ferris, 
P. D. Tuckett, and C. E, Gardner had been elected by the 
council as ordinary members, and Mr. G. S. Brady, of 
Sunderland, as a corresponding member. 
Mr. H. Ferris exhibited a specimen of the green wood- 
pecker, shot at Clareham, near Yatton, one of many birds 
which were rapidly becoming rare, from no assignable 
cause. The president suggested that an investigation into 
these causes and a list of such birds would form an exceed- 
ingly useful communication to the society, and be a very 
Igood illustration of how much information might be ob- 
itained by a little attention to natural history pursuits. 
Mr. W. L. Carpenter, the hon. reporting secretary, then 
read a paper on gun-cotton. He commenced by regretting 
that the papers before a society which numbered so many 
members were so few in number that it was necessary for 
the officers of the society themselves to provide subjects for 
the evening meetings, and then alluded to the great atten- 
tion which the subject he had chosen was now attracting, 
deservedly, from its numerous applications, Gun-cotton 
was, he said, a remarkable illustration of the chemical doc- 
trine of substitution, which he had explained in that theatre 
on a former occasion. As early as 1813 the remarkable 
action of nitric acid upon lignin, starch, &c., bad been 
noticed, and in 1838 Pelouze, after investigating the properties 
lof this product, then called xyloidin, had suggested its appli- 
ication to artillery. In 1846 Schonbein showed its detonating 
properties at the Southampton meeting of the British Associa- 
tion, and compared it with gunpowder. Many analyses were 
then made to ascertain its composition, wit^h unsatisfactory 
results, and it was reserved for Mr. E. Hadow to publish, in 
1854, his valuable and complete researches into this curious 
substance. Cotton, or cellulose, was composed of atoms of 
carbon, oxygen, and hydrogen, represented by the formula 
c H o 
G 10 5. Some of these atoms could not be removed withoH t 
destroying the very existence of the substance, whilst others 
could be taken out, provided they were immediately replaced 
by certain other atoms. In the formation of gun cotton 
some of the atoms of hydrogen in ordinary cotton were re- 
placed by tbe same number of atoms of a substance termed 
N o 
hyponitric acid, 2, derived from the nitric acid in which 
the cotton was soaked. There were four definite compounds, 
with varying quantities of hyponitric acid, according to the 
degree of concentration of the acid employed. The highest 
and mpst explosive, termed chemically 'Uri-nitro-cellulose," 
had three of the ten atoms of hydrogen replaced, and this 
was the compound he specially wished to speak of. The 
three lower compounds, which were less explosive, were 
used in the manufacture of collodion, so useful to the pho- 
tographer and the sargeon, which was simply a solution of 
gun cotton in a mixture of alcohol and ether. Shortly after 
Schonbein had announced his discovery, gun cotton was 
experimented on by a committee of tbe German Confedera- 
tion, one of the members of which. Baron von Lenk, con- 
tinued to devote himself to its study, and in 1852 it was 
partially adopted by the Austrian Government for artillery, 
and applied with great success in mining and submarine 
operations. With some intermissions, partly caused by 
prejudice against its use, it was employed for some years, 
and ultimately a committee of eminent scientific men re- 
ported most favourably upon it as regarded its stability, explo- 
