stances that have been N

odge, Zenger, and Melse

from Lig

sive agents, under the form of smokeless powders. The nitro-explosives belong to the so-called High Explosives, and may be defined as any chemical compound possessed of explosive properties, or capable of combining with metals to for

ven in Order of Council, N

e, sugar, phenol, wood, straw, and even such substances as treacle and horse-dung. Some of these are not made upon the large scale, others are but little used. Those of most importance are nitro-glycerine and nitro-cellulose. The former enters into the composition of all dyna

anic substance in which the NO_{2} group, known as

n glyc

3}H_{5}

constituent of fats, the hydrogen atoms are replaced by the NO_{2} group, to form the highly explo

C_{3}H_{5

H_{5}(ONO_{2})_{3}, or the tri- nitrate, is

salts when treated with nitric and sulphuric acids. The hexa-nitrate, or gun-cotton, has the formula, C_{12}H_{14}O_{4}(ONO_{2})_{6}; and collodion-cotton, pyroxylin, &c., form the lower nitrates, i.e., the t

ne, C_{6}H_{4}(NO_{2}){2}, in which one and two atoms are replaced by the NO{2} group. The latter of these compounds is used as an explosive, and enters into the composition of such well-known explosives as roburite, &c. The presence of nitro groups in a substance increases the difficulty of further nitration

tained, and very little of the ortho. The substitution takes place, however, almost entirely in the meta position, if a nitro, carboxyl, or aldehyde group be present. Ordinary phenol, C_

emistry," Prof. Hjelt. T

.D

itrated, a compound is formed known as tri-nitro-phenol, or picric acid, C_{6}H_{2}(NO_{2}){3}OH, which is used very extensively as an explosive, both as picric acid and in the form of picrates. Another

ration:

: META-DINITR

ic acid fermentation of sugar and closely related to the sugars, with nitric and sulphuric

ch. They are formed by acting upon potato starch dried at 100° C. with a mixture of nitric and sulphuric acids at a temperature of 20° to 25° C. Rice starch has also been used in its production. Muhlhauer proposes to use this body as a smokele

Bevan. and also by Mühlh?uer. The former chemists give jute the formula C_{12}H_{18}O_{9},

O_{3} = 3H_{2}O + C_{12

ion of jute fibre. Messrs Cross and Bevan say, "In other words, if we represent the ligno-cellulose molecule by a C_{12} formula, it will contain four hydroxyl (OH) groups, or two less

that a number of raw materials containing cellulose (chiefly as cotton) can be obtained at from ￡10 to ￡25 a ton, and yield also 150 to 170 per cent. of explosive material when nitrated (whereas jute only gives 154.4 per cent.), and are in

the event of an explosion they will offer less resistance, and will cause much less danger than brick or stone buildings. When an explosion of nitro-glycerine or dynamite occurs in one of these buildings, the sides are generally blown out, and the roof is raised some considerable height, and finally descends upo

ntispiece).[A] These mounds are of great value in confining the force of the explosion, and the sides of the buildings being thrown against them are prevented from travelling any distance. In gunpowder works it is not unusual to s

tting in it, and which it is claimed will not let a splinter fall, even if badly cracked. The mounds are then erected right up against the walls of the building, exceeding them in height by several metres

ust give a plan (drawn to scale) of the proposed factory or magazine, and the site, its boundaries, and surroundings, and distance the building will be from any

plosives Act, 3

OF NITRO-GLYCERINE CONDUIT. a,

would be more or less unsuitable for the manufacture of nitro-glycerine, where a number of buildings are required to be upon different levels, in order to allow of the flow of the liquid nitro- glycerine from one building to another through a system of conduits. These conduits (Fig. 1), which are generally made of wood and lined with lead, the space between the woodwork and the le

otash dissolved in methylated spirit and water, and afterwards with water alone. This decomposes the nitro-glycerine forming glycerine and potassium nitrate. It will be found that the mixed acids attack the lead rather quickly, forming sulphate and nitrate of lead, but chiefly the former. It is on this account that it has been proposed to use pipes made of gu

the secondary separator; (5) the deposit of washings; (6) the settling or precipitation house; and each of these buildings must be on a level lower than the preceding one, in order that the nitro-glycerine or acids may flow

h this object they should be made double, and the intervening space filled with cinders. The roof also should be kept whitewashed, and the windows painted over thinly with white paint. A thermometer should be suspended in every house. It is very essential that the floors of all these buildings sh

3} + 3KOH = C{3}H_{

rthelot, Comptes Rendus,

d pipes should be placed about the works with a good pressure of water, the necessary hose being kept in certain known places where they can be at once got at in the case of fire, such as the danger area laboratory, the foreman's office, &c. It is also desirable that the above precautions against fire should be tested once a week. With regard to the heating of the various buildings in the winter, steam

sirable or safe to wear outside the works. It is also necessary that these clothes should not contain any pockets, as this lessens the chance of matches or steel implements being taken upon the danger area. Changing houses, one for the men, and another for t

.-MELSENS SYSTEM OF L

shall have attached thereto a sufficient lightning conductor, unless by reason of the construction by excavation or the position of such magazine or building, or otherwise, the Secretary

sor Melsens, of Brussels, and Professor Zenger, of Prague, but first suggested by the late Professor Clerk-Maxwell. In a paper read before the British Association, Clerk-Maxwell proposed to protect powder

of an aigrette or brush with five or seven points, the central point being a little higher than the rest, which form with it an angle of 45°. He employs for the most part galvanised-iron wire. He places all metall

Belgian Acade

zines or store buildings placed in very exposed situations. Zenger's system is identical with that of Melsens, and has been

3.-FRENCH SYSTEM OF

nch military authorities also protect magazines by erecting two or more lightning-rods on poles of sufficient height placed c

a height, and so situated, that no danger is incurred in igniting the powder-dust in the air by the lightning discharge at t

_.-GOVERNMENT SYSTEM OF

BUIL

_.-GOVERNMENT SYSTEM OF

BUIL

strike buildings at a single point, but rather in a sheet; hence, in such cases, or in the event of the globular form being assumed by the lightning, the aigrette will constitute a much more effective protection than a single point. As to the spacing of conducto

explosives packed in metal cases, and hence would present a line of smaller electrical resistance than the surrounding earth would offer to the ligh

ngles and the prominent portions of a building being the most liable to be struck, the conductors should be carried over and along these projections, and theref

he test is to determine the resistance of the earth-connection, and to localise any defective joints or parts in the conductors. The best system of testing the conductors is to bala

to measure roughly up to 2,000 ohms. Mr R. Anderson's apparatus is also very handy, consisting of a case containing three Leclanché cells, and a galvanometer with a "tangent" scale and certain stan

s, such as gelatine dynamite and gelignite, both of which substances consist of a mixture of gun-cotton dissolved in nitro-glycerine, with the addition of varying proportions of wood-pulp and saltpetre,

4, and of nitric acid of a gravity of 1.5, which has been cooled by a freezing mixture, that an oily liquid is formed." This liquid is nitro-glycerol, or nitro-glycerine, which for some years found no important use

in some absorbent earth, and thus forming the material that is now known a

ery great advances in the manufacture. Mowbray was probably the first to use compressed air for the purpose of keeping the liquids well agitated dur

is much lower. The two mixtures are mixed in the proportions-Glycerine, 100; nitric acid, 280; and sulphuric acid, 600. They state that the rise of temperature upon mixing is limited from 10° to 15° C.; but this method requires a period of twenty-four hours to complete the nitration, which, considering the danger of keeping the

, 75; and Desortiaux, "Trai

decomposition, and thus to keep up the strength of the nitric acid, otherwise lower nitrates of glycerine would be formed that are soluble in water, and which would be lost in the subsequent process of washing to which the nitro-compound is

O_{3} = C{3}H_{5}(NO_

s being regarded as a nitric ether of glycero

HNO_{3} = C{3}H_{5}(

2

O

rine is C_{3}H_{8}O_

O

NO

no-nitrate of glyc

O

NO

e or (nitro-glycerine

NO

i-molecules of hydroxyl in the glycerin

ve 2.47 lbs. of nitro-glycerol ((227+1)/92 = 2.47), but in practice the yield is only about 2 lbs. to 2.22, the loss being accounted for by the unavoidable formation of some of the lower nitrate, which dissolves