I have treated five different samples: 1. The government powder made at
Waltham Abbey; 2. Glass gunpowder made by John Hall, Dartford; 3. The
treble strong gunpowder of Charles Lawrence and Son; 4. The Dartford
gunpowder of Pigou and Wilks; 5. Superfine treble strong sporting
gunpowder of Curtis and Harvey. The first is coarse-grained, the others
are all of considerable fineness. The specific gravity of each was taken
in oil of turpentine: that of the first and last three was exactly the
same, being 1·80; that of the second was 1·793, all being reduced to
water as unity.