~Ammonite.~--This explosive was originally made at Vilvorde in Belgium, under the title of the Favier Explosive, consisting of a compressed hollow cylinder composed of 91.5 per cent. of nitrate of ammonia, and 8.5 per cent. of mono-nitro-naphthalene filled inside with loose powder of the same composition. The cartridges were wrapped in paper saturated with paraffin-wax, and afterwards dipped in hot paraffin to secure their being water-tight. The Miners' Safety Explosives Co., when making this explosive at their factory at Stanford-le-Hope, Essex, abandoned after a short trial the above composition, and substituted di-nitro-naphthalene 11.5 per cent. for the mono-nitro-naphthalene, and used thin lead envelopes filled with loose powder slightly pressed in, in place of the compressed cylinders containing loose powder. The process of manufacture is shortly as follows:--132-3/4 lbs. of thoroughly dried nitrate of ammonium is placed in a mill pan, heated at the bottom with live steam, and ground for about twenty minutes until it becomes so dry that a slight dust follows the rollers; then 17-1/2 lbs. of thoroughly dry di-nitro-naphthalene is added, and the grinding continued for about ten minutes. Cold water is then circulated through the bottom of the pan until the material appears of a lightish colour and falls to powder. (While the pan is hot the whole mass looks slightly plastic and of a darker colour than when cold.) A slide in the bottom of the pan is then withdrawn, the whole mass working out until the pan is empty; it is now removed to the sifting machine, brushed through a wire sieve of about 12 holes to the inch, and is then ready for filling into cartridges. The hard core is returned from the sifting machine and turned into one of the pans a few minutes before the charge is withdrawn.