Part 10 (2/2)
Non-nitrated cotton 0240 ”
Nitrogen 1164 ”
Total ash 025 ”
The soluble cotton, which is a mixture of the tetra- and penta-nitrates, is soluble in ether-alcohol, and also in nitro-glycerine, and un-cotton), C_{12}H_{14}O_{4}(ONO_{2})_{6}, is not soluble in the above liquids, although it is soluble in acetone or acetic ether It is very essential, therefore, that the nitro-cotton used in the elatine explosives should be as free as possible froun-cotton, otherwise little luelatine
The non-nitrated or unconverted cotton should also be very low, in fact considerably under 1/2 per cent
The nitro-cotton and the nitro-glycerine used should always be tested before use by the heat test, because if they do not separately stand this test, it cannot be expected that the gelatine made from theh both the ingredients stand this test separately before being mixed, that after the process of manufacture one or other or both fail to do so
The nitro-cottonis that which has been finely pulped If it is not already fine enough, it h a fine brass wire sieve It will be found that it requires to be rubbed through by hand, and will not go through at all if in the least degree dae of nitrogen in the nitrated cotton should be over 11 per cent It should be as free as possible fronition, not enerally packed wet in zinc-lined wooden boxes, will require to be dried, as it is very essential indeed that none of the elatine should contain elatine subsequently erous and comparatively valueless It will also be much more difficult to lycerine if either contains water
In order to find out how long any sample of cotton requires to be dried, a sample should be taken frorhed, and the whole then placed in the water oven at 100 C, and dried for an hour or so, and again weighed, and the percentage of uide to the ti house Saenerally contain fro for a period of forty-eight hours, a saain dried in the oven at 100 C, and the moisture determined, and so on at intervals until the bulk of the cotton is found to be dry, ie, to contain from 025 to 05 per cent ofthe process of re itself, the cotton should be exposed to the air as little as possible, as dry nitro-cotton absorbs as much as 2 per cent of e dryness
The drying house usually consists of a wooden building, the inside of which is fitted with shelves, or rather framework to contain drawers,bottoh the shelves and over the surface of the cotton, which is spread out upon them to the depth of about 2 inches This current of air can be obtained in any way that may be found convenient, such as bypassed over hot bricks, or hot-water pipes before entering the building The cotton should also be occasionally turned over by hand in order that a fresh surface may be continually exposed to the action of the hot air The building itself may be heated by means of hot-water pipes, but on no account should any of the pipes be exposed They should all be most carefully covered over ork, because when the dry nitro-cotton is et into the air, and gradually settling on the pipes,ledges, &c, ht cause explosion It is on this account that this house should be very carefully swept out every day It is also very desirable that the floor of this house should be covered with oilcloth or linoleu soft, it lessens the friction
List shoes should always be worn in this building, and a ther up somewhere about the centre of the house, and one should also be kept in one of the trays to give the temperature of the cotton, especially the bottom of the trays The one nearest to the hot air inlet should be selected If the temperature of the house is kept at about 40 C it will be quite high enough The building must of course be properly ventilated, and it will be found very useful to have the wallsspace filled with cinders, and the roof covered with felt, as this helps to prevent the loss of heat through radiation, and to preserve a uniform temperature, which is very desirable
The dry cotton thus obtained, if not already fine enough, should be sifted through a brass sieve, and packed away ready for use in zinc air-tight cases, or in indiarubber bags The various gelatine coelatine, are elatine dyna certain proportions of wood-pulp and potassiu are analyses of some typical sanite Dynalycerine 60514 71128 9294 per cent
Nitro-cellulose 4888 7632 706 ”
Wood-pulp 7178 4259”
Potassium nitrate 27420 16720”
Water0261”
The gelignite and gelatine dynaelatine, thickened up with a elatine is weight for weight more powerful, it is more difficult toso tests The higher percentage of nitro-cotton, too, makes it expensive
When the dry nitro-cotton, which has been carefully weighed out in the proportions necessary either for blasting gelatine or any of the other gelatine explosives, is brought to the gelatine h, and the necessary quantity of pure dry nitro- glycerine poured upon it The whole is then well stirred up, and kept at a teo her temperatures may be used if the nitro-cotton is very obstinate,[A] and will not dissolve Great caution must, however, be observed in this case The mixture should be constantly worked about by the workman with a wooden paddle for at least half an hour At a telycerine acts upon the nitro-cotton and forelatinisation is very imperfect indeed, and at temperatures under 40 C takes place very slowly
[Footnote A: Generally due to the nitro-cotton being damp]
[Illustration: FIG 30--WERNER, PFLEIDERER, & PERKINS' MIXING MACHINE]
The limit of temperature is 50 C or thereabouts Beyond this the jelly should never be allowed to go, and to 50 only under exceptional circumstances
The tank in which the jelly is e of hot water between its inner and outer linings A series of such tanks are generally built in a wooden fras are made to communicate, so that the hot water can flow from one to the other consecutively The temperature of the water should be about 60 C if it is intended to gelatinise at 45 C, and about 80 if at 50 C; but this point must, of course, be found by experiement should be made to enable the workman to at once cut off the supply of hot water and pass cold water through the tanks in case the explosive becomes too hot