92 Proposed Substitutes for Gunpowder. 
equal charge consisting of the yarn wound very loosely, 
because the pressure of gas established by the first ignition 
of the charge renders the compact packing of the gun- 
cotton powerless to resist the instantaneous penetration of 
flame between the separate layers of the material. The 
assertion that a power had been acquired of controlling the 
explosive action of gun-cotton in a firearm by simply 
varying the compactness with which the material was 
twisted or wound, has, therefore, proved quite erroneous. 
There are, however, two methods of reducing the rapidity 
of explosion of gun-cotton, which are much more likely to 
furnish successful results. The one consists in diluting the 
material by its admixture either with a less explosive 
variety of gun-cotton or with some inexplosive substance, 
such, for instance, as the cotton in its original form. The 
latter mode of dilution has recently been applied by 
Messrs. Prentice to the construction of cartridges for sport- 
ing purposes, and they describe the results already arrived 
at as very promising. The second method of controlling 
the explosion of gun-cotton consists in consolidating the 
material by pressure into compact homogeneous masses, 
and in confining the first fenition of such compressed gun- 
cotton in the bore of the gun, to certain surfaces. The 
gun-cotton fibre in the form of yarn or plait may be com- 
pressed into very compact masses by being rammed into 
strong cylinders of pasteboard or other suitable material ; 
but much more perfectly homogeneous and solid masses 
are produced, independently of cylinders or other cases, by 
a method which Mr. Abel has recently elaborated, and 
which consists in reducing the gun-cotton fibre to a fine 
state of division or pulp, as in the process of paper-making, 
and in converting this pulp by pressure into solid masses 
of any suitable form or density. 
This method of operating affords also special eieiities 
for combining both methods, dilution and compression, of 
reducing the explosive violence of gun-cotton. The 
material is, in fact, operated upon by this system, in a 
manner exactly corresponding to the processes by which 
the explosive action of gunpowder is regulated to so re- 
markable an extent. Some results, which are admitted by 
the most sceptical as encouraging, have already been 
arrived at, in the systematic course of experiments which 
are in progress, with the object of applying the methods 
of regulation, pointed out, to the reduction of gun-cotton 
to a'safe form for artillery purposes. Its arrangementina 
