238 
MR. ABEL’S RESEARCHES OH GUN-COTTON. 
concluded from three years’ experience, the close packing of gun-cotton in this damp 
state is not even in the slightest degree injurious to the structure of the fibre, no 
tendency whatever of the material to become rotten when thus preserved has yet been 
discovered. On the contrary, most decided evidence has been obtained that gun-cotton 
when kept in a damp condition is very considerably more permanent than ordinary cotton, 
or vegetable substances of similar nature. Thus, many hanks of the gun-cotton stored 
in the damp state were tied with tape and string for purposes of distinction. Upon 
examining these hanks ten months after they had been packed, the tape was in all 
instances found to be almost if not entirely destroyed, crumbling away when touched, 
and being transformed principally into fungoid bodies ; the strings were also quite rotten 
and covered with vegetable growth, but the gun-cotton even in close proximity to them 
was unaffected. Similar results were observed in the case of a number of samples of 
gun-cotton which had been packed in a dry condition in paper envelopes and placed in 
a small very damp chamber. About twelve months after they were stored the paper 
wrappings and strings were found to be covered with vegetable growth and partly de- 
stroyed, while no vestiges of similar growth or other signs of change were detected in 
the gun-cotton. A wooden reel having some gun-cotton yam wound upon it which had 
been kept in the same locality was also found to be covered in all exposed parts with 
fungoid growth, but the gun-cotton in immediate contact with the latter upon the wood 
was unaffected and perfectly free from mildew. This specimen has been preserved 
for another year in a damp atmosphere upon the reel and exposed to light. In some 
parts the mildew has extended to the gun-cotton immediately in contact with the wood, 
but the rest of the material is unaffected. 
Pakt IV._ OTHER OBSERVATIONS, INSTITUTED UPON LARGE QUANTITIES OE GUN-COTTON. 
A series of observations has been conducted for about three years under my direction 
and in accordance with a programme approved of by the Committee on Gun-cotton, for 
the purpose of ascertaining the effects of storage in considerable quantites, under the 
ordinary atmospheric conditions of this country, and under conditions, as regards tempe- 
rature, representing the extremes likely to be met with in tropical climates or in warm 
localities ( e . g. the magazines of ships). The gun-cotton, which, with these objects in 
view, was closely packed in large ammunition-boxes, comprised not simply parcels of the 
material as obtained by following the present system of manufacture, but also others in 
the production of which modifications had purposely been introduced with the view of 
determining the influence which might be exerted, by possible accidental departure from 
one or other of the fixed regulations of manufacture, upon the stability of the material. 
The following is a summary of the observations made up to the present time. 
I. Storage of Gun-cotton under ordinary conditions ' of temperature. 
(a) The gun-cotton being closely packed in a damp condition. — Attempts have been 
made to ascertain whether the close packing of gun-cotton in a damp condition would 
