36 REPORT—1890. 
substances are then free to come into contact, and their very rapid mixture 
is promoted by the rotation of the shell, so that, almost by the time that it 
is projected from the gun, its contents, at first quite harmless, have become 
converted into a powerfully explosive mixture, ready;to come into opera- 
tion through the action of the fuse. Although safety appears assured by 
this system, the comparatively complicated nature of the contrivance, and 
the loss of space in the shell thereby entailed, place it at a disadvantage, 
especially since some other very violent explosive agents have come to 
be applied with comparative safety in shells. 
Between four and five years ago intelligence first reached us of 
marvellously destructive effects produced by shells charged with an 
explosive agent which the French Government was, elaborating. The 
reported results surpassed any previously recorded in regard to violently 
destructive effects and great velocity of projection of the fragments of 
exploded shells, and it was asserted that the employment of this new 
material, Mélinite, was unattended by the usual dangers incident to this 
particular application of violent explosive agents, an assertion scarcely 
consistent with accounts which soon reached us of several terrible calami- 
ties due to the accidental explosion of shells loaded with Mélinite. 
Although the secret of the precise nature of Mélinite has been 
extremely well preserved, it transpired ere long that extensive purchases 
were made in England, by or for the French authorities, of one of the 
many coal-tar derivatives which for some years past has been extensively 
manufactured for tinctorial purposes, but which, although not itself classed 
among explosive bodies until quite lately, had long before been known 
to furnish, with some metals, more or less highly explosive combinations, 
some of which had been applied to the production of preparations sug- 
gested as substitutes for gunpowder. 
The product of destructive distillation of coal from which, by oxida- 
tion, this material is now manufactured, is the important and universally- 
known antiseptic and disinfectant, carbolic acid, or phenol. Originally 
designated carbazotic acid, the substance now known as picric acid was 
first obtained in small quantities as a chemical curiosity by the oxidation 
of silk, aloes, &c., and of the well-known blue dye indigo, which thus 
yielded another dye of a brilliant yellow colour. To the many who may 
regard this interesting phenol-derivative as a material concerning the 
stability and other properties of which we have little knowledge, it will 
be interesting to learn that it has been known to chemists for more than a 
century. It was first manufactured in England for tinctorial purposes by 
the oxidation of a yellow resin (Xanthorrhea hastilis), known as Botany 
Bay gum. Its production from carbolic acid was developed in Manchester 
in 1862, and its application as a dye gradually extended, until, in 1886, 
nearly 100 tons were produced in England and Wales. 
Although picric acid compounds were long since experimented with as 
explosive agents, it was not until a very serious accident occurred, in 1887, 
