not manufactured. Among the best known after the ordinary No. 1 dynamite
are forcite, ammonia dynamite, litho-fracteur, rendock, Atlas powder,
giant powder, and the various explosive gelatines. They all contain nitro-
glycerine, mixed with a variety of other substances, such as absorbent
earths, wood-pulp, nitro-cotton, carbon in some form or other, nitro-
benzol, paraffin, sulphur, nitrates, or chlorates, &c. &c.

~Blasting Gelatine and Gelatine Dynamite.~--The gelatine explosives
chiefly in use are known under the names of blasting gelatine, gelatine
dynamite, and gelignite. They all consist of the variety of nitro-
cellulose known as collodion-cotton, i.e., a mixture of the penta- and
tetra-nitrates dissolved in nitro-glycerine, and made up with various
proportions of wood-pulp, and some nitrate, or other material of a similar
nature. As the gun-cotton contains too little oxygen for complete
combustion, and the nitro-glycerine an excess, a mixture of the two
substances is very beneficial.

Blasting gelatine consists of collodion-cotton and nitro-glycerine without
any other substance, and was patented by Mr Alfred Nobel in 1875. It is a
clear, semi-transparent, jelly-like substance, of a specific gravity of
1.5 to 1.55, slightly elastic, resembling indiarubber, and generally
consists of 92 per cent. to 93 per cent. of nitro-glycerine, and 7 to 8
per cent. of nitro-cotton. The cotton from which it is made should be of
good quality. The following is the analysis of a sample of nitro-cellulose
which made very good gelatine:-

Soluble cotton 99.118 per cent.
Gun-cotton 0.642 "
Non-nitrated cotton 0.240 "
Nitrogen 11.64 "