272 
MODERN GUNPOWDER AND CORDITE. 
bore of the gun, and further, these powders, by their uniformity of 
action, ensure similarity of results. The diagrams here indicate what 
the pressures are with the old explosive R.L.Gr. The dark area repre¬ 
sents the rapid increment of pressure and the equally rapid decrease 
which takes place when the charge is ignited. 
It may be well now to discuss the methods by which gunpowder has 
been developed into a “ reliable propellant,” and, as briefly as possible, 
to deal with the outlines of its manufacture. Let us note the new 
features in the table before us :— 
KN0 3 
s. 
c. 
Water is no longer looked upon as an unavoidable evil; its influence 
in reducing the pressure in the early stage of ignition, and the steam 
or gases produced from it hold a recognised position in the composition 
of the new propellant. These two vessels of water before you represent 
actually, the maximum quantity and the minimum quantity which 
should be present in each barrel containing 100 lbs. of service gun¬ 
powder. The larger quantity is 2*2 per cent, the maximum limit; and 
the smaller 1 per cent., the minimum limit for ordinary powders. 
It is well to realise that the portion of the old maxim “ keep your 
powder dry,” must be considerably modified, and that, though modern 
gunpowder is designed to stand the ordinary changes of climate to 
which most of our war material is exposed, yet it may resent abnormal 
or artificial heating, or baking in magazines close to engine-rooms or 
boilers, as treatment unworthy of its dignity ! I might say in passing, 
that the quantity of water shown in the table (Table A) is the normal 
amount which gunpowder retains under ordinary conditions ; that is to 
say that it will not part with or absorb more than that quantity unless 
subjected to abnormal treatment. We may also observe that the char¬ 
coal has now fixed proportions of carbon, oxygen and hydrogen, which 
(when properly prepared) it should always contain. The old charcoal 
was merely burnt wood, and nobody knew anything about it. Now 
there is a careful analysis made of charcoal, and the proportions of 
carbon, oxygen and hydrogen are always adhered to. 
As it is not proposed in this lecture to discuss the manufacture of 
gunpowder in detail, I shall only name the processes, each of which 
TAELS A .— Gunpowders. 
Old. Modern. 
BlacJc. Brown. 
75 saltpetre. 79 saltpetre. 
10 sulphur . 3 sulphur. 
C willow C carbon. 
, 16 charcoal < alder >■. 18 charcoal (straw) ■< hydrogen. 
(. dogwood ) (. oxygen. 
1,7 1 water ( h y drogen ’ 
2*2 ) watei 1 oxygen. 
Black. 
75 saltpetre. 
10 sulphur. 
C carbon. 
15 charcoals hydrogen. 
(.oxygen. 
«ter Uy dl '°S en ' 
13) (.oxygen. 
