_______________________________________________________

________________
|                  |            |           |            |              |
|                  |    Gas     |           |            |              |
|                  | Pressure.  | Velocity. |  Pattern.  | Penetration. |
|__________________|____________|___________|____________|__

____________|
|                  |            |           |            |              |
|                  |Atmospheres.|  Metres.  |            |   Sheets.    |
|                  |            |           |            |              |
|Fine-grained black|            |           |            |              |
|powder, standard  |            |           |            |              |
|charge            |   514.2    |   280     | 78.6 = 66% |    19.O      |
|                  |            |           |            |              |
|Coarse-grained    |            |           |            |              |
|black powder,     |            |           |            |              |
|standard charge   |   473.4    |   281.4   | 78.2 = 65% |    19.4      |
|                  |            |           |            |              |
|Schultze powder,  |            |           |            |              |
|42 grains         |   921.0    |   290.0   | 64.2 = 54% |    20.2      |
|                  |            |           |            |              |
|Schultze powder,  |            |           |            |              |
|45 grains         |  1052.8    |   305.8   | 52.2 = 42% |    20.6      |
|                  |            |           |            |              |
|E.G. smokeless,   |            |           |            |              |
|42 grains         |   920.2    |   298.4   | 81.4 = 67% |    18.8      |
|                  |            |           |            |              |
|Walsrode,         |            |           |            |              |
|29 grains         |   586.4    |   280.6   | 83.0 = 69% |    19.0      |
|__________________|____________|___________|____________|__

____________|

Barometer, 760 mm.  Thermometer, 30 deg.  C. Hydrometer = 65.  Wind, S.W.

Picric Powders.—­The chief of these is Melinite, the composition of which is not known with certainty.  It is believed to be melted picric acid together with gun-cotton dissolved in acetone or ether-alcohol.  Walke gives the following proportions—­30 parts of tri-nitro-cellulose dissolved in 45 parts of ether-alcohol (2 to 1), and 70 parts of fused and pulverised picric acid.  The ether-alcohol mixture is allowed to evaporate spontaneously, and the resulting cake granulated.  The French claim, however, that the original invention has been so modified and perfected that the melinite of to-day cannot be recognised in the earlier product.  Melinite has a yellow colour, is almost without crystalline appearance, and when ignited by a flame or heated wire, it burns with a reddish-yellow flame, giving off copious volumes of black smoke.  Melinite as at present used is said to be a perfectly safe explosive, both as regards manufacture, handling, and storage.