THE ROYAL ARTILLERY INSTITUTION. 
51 
till quite up to the standard in such particulars. But in the case of 
powder supplied by contract, some description must be given of the way 
such points are judged. The qualities enumerated can be judged by 
eye and hand alone, and require of course a considerable amount of 
experience to enable an observer to come to a trustworthy opinion. 
(al) Colour .—The colour of finished powder depends on two points 
principally—viz. first, the colour of the charcoal of which the powder has 
been made ; and secondly, the amount of moisture that has been added 
to the charges before leaving the incorporating mills. The more under** 
burnt the charcoal is, the browner will be the powder. Some powders 
made with very slack-burnt charcoal, have a very decidedly red tint, 
which is easily detected on crushing the grains to dust. It is needless 
to say that, as regards colour, the powder under examination must be 
the same as the standard powder of the particular class to which it 
belongs. Any great variations in the charcoal would no doubt be 
detected in the subsequent processes of proof; for powder made with 
under-burnt charcoal will give a decidedly higher velocity to a bullet 
than that made with a more highly burnt, and consequently denser 
charcoal; and it will absorb moisture more readily than the latter. 
Nevertheless, under-burnt charcoal appears to offer certain advantages 
in small-arm powders; so that the reader must remember that there is 
no absolute rule to lay down—all examinations of the colour of powder 
must be comparative. As regards the other point—the amount of 
moisture which has been added to the charges in the mills—it is found 
that when the charges are taken off the mill-beds with an excess of 
moisture in them, and are subjected to pressure soon afterwards, the 
resulting powder is harder and of a blacker colour than if made other-* 
wise. If two powders, therefore, be found to be of equal density, and if 
the one be blacker in colour and harder than the other, it has been 
worked heavier ; that is, it has been taken off the mill-bed with a 
greater amount of moisture in it. There is no test for hardness, which 
can only be estimated by crushing the grain between the finger and the 
thumb. A powder which has been worked with a great amount of 
moisture, may be expected to give indifferent results when flashed; 
but, practically, the differences which powders present in this respect 
are seldom of any consequence. 
(b.) Glaze. —Examination as to this point must also be comparative, as 
must also be that for 
(c.) Crispness and hardness of grain .—In these matters, experience is 
the only safe guide. It must be remembered that it is not the pro¬ 
vince of the manufacturer to decide what is the best description of 
powder to turn out, to what extent it shall be glazed, or what is the 
proper amount of hardness that the grains should have. 8uch matters 
are decided by the experimental committees, who, after trying various 
powders submitted to them by the manufacturer, make choice of a 
powder which fulfils best all that is required of it. Once the pattern 
of powder—so to speak—has been settled, it is the manufacturers duty 
to make all future issues as nearly identical in all points with the 
