Part 7 (2/2)

showed that CO was present in traces only, whilst the fuers in connection with the Manufacture of Guncotton, &c~--Of all the nitro coun-cotton and collodion-cotton The fact that the Stowmarket Factory is within five minutes' walk of the town sho safe the arded With the exception of the nitration and the compression into blocks or discs, the whole process is worked with a large excess of water, and the probability of an explosion is thus reduced to athe precautions that should, however, be taken, are--first, the careful extraction of the resinous and soluble substances froo by Sir FA Abel that the instability of the gun-cotton first land and Austria was chiefly due to these co the cotton in a soda solution

The actual nitration of cotton is not a dangerous operation, but the operations of wringing in the hydro-extractors, and washi+ng the nitro- cotton after it leaves the first centrifugal machine, are so-out nitro-cotton at once coe excess of water, ie, is at once ie it is especially liable to decomposition, which, once started, is very difficult to stop The warmer the mixture and the less water it contains, the more liable it is to decomposition; hence it is that on waral machines are most likely to fire The commencement of decomposition may be at once detected by the evolution of red fue quantity of water in the beater and poacher it is safe

In order that the final productqualities, it is necessary that it should be washed completely free fro the material to assue quantity of water, does a good deal to get rid of the free acid, but the boiling process is absolutely necessary It has been proposed to neutralise the free acid with a dilute solution of ammonia; and Dr CO Weber has published so upon this treatment He found that after treathtly yellowish tinge, which was a sure sign of alkalinity It was then rehly dried between folds of filter paper, and afterwards dried in an oven at 70 C After three hours, however, an explosion took place, which entirely destroyed the strong copper oven in which the nitro- cotton (about one oz) had been drying The explosion was in some respects remarkable The pyroxyline was the di-nitro-cellulose (or possibly the penta-nitro?), and the te point of this material (40 C would have been a better tenition point of his di-nitro-cellulose, and found it to be 194 to 198 C, and he is therefore of opinion that the explosion was due to the treatment of the partially washed material with ammonia A certain quantity of ammonium nitrate was probably formed, and subsequently dried upon the nitro-cellulose, in a state of very fine subdivision The faintest trace of acid would then be sufficient to bring about the explosive ignition of the aun-cotton or collodion-cotton is also a soerous operation A temperature of 40 C (104 F) should not be exceeded, and thermometers should be placed in the nitro-cotton, and the temperature frequently observed An electric alar house Great care must also be taken that there are no exposed hot-water pipes or stoves in the drying house, as the fine gun-cotton dust produced by the turning orof the material upon the shelves would settle upon such pipes or stoves, and beco hot, would be very sensitive to the least friction The floor also should be covered with linoleum or indiarubber When hot currents of air are un-cotton becomes electrified

It is important, therefore, to provide some means to carry it away Mr WF Reid, FIC, was the first to use metal frames, carriers, and sieves, upon which is secured the cloth holding the gun-cotton, and to earth theun-cotton into blocks, discs, &c, is also attended with considerable risk Mr O Gutters in the Manufacture of Explosives” (_Jour Soc Cheun-cotton into cartridges requires far unpowder, as this is done in a warun-cotton even when cold, isout of the centrifugal h a sieve, in order to detect nails or ot into it What has been said as to gunpowder presses applies still h the latter are always hydraulic presses Generally the pistons fit the mould perfectly, that is to say, they make aspiration like the piston of a puth of time will stand the constant friction of compression, and after soreatest compression takes place The best metal for this purpose has proved to be a special steel made by Krupp, but this also is only relatively better; for pistons I prefer hard cast iron If the position of the moulds and pistons is not exactly the salish 'binding') will take place, viz, the erous friction will result” ”Of course, it is necessary to protect thecompression At Waltham Abbey they have a curtain made of shi+p's hawsers, which is at the same time elastic and resistant”

Mr Guttmann has found that a partition wall 12 inches thick, ives very effective protection A door in this partition enables the worket to the press, and a conical tube penetrates the wall, enabling the man to see the whole work fro, should be of glass, so as to give the explosion a direction

~Trench's Fire-extinguishi+ng Compound~ is manufactured by the Cotton Powder Coe Trench, FCS, the er of the Coes of tonite, when used in coal e of tonite, dynaelatine dynamite is put inside a few ounces of this mixture, and then fired, not the least trace of flame can be observed, and experiments appear to show that there is no flanated with a22 shows the , and surrounding it with the fire-extinguishi+ng compound, _aa_ The attachment of the fuse and detonator is also shown

[Illustration: FIG 22--TRENCH'S FIRE-EXTINGUIshi+NG CARTRIDGE]

The following report (taken from the _Faversham News_, 22nd Oct 1887) of experiments conducted in the presence of several scientific and ht-iron tank, of 45 cubic feet capacity, had been sunk level with the ground in the as had been laid on, for a purpose that will be explained later on The charges were fired byplaced from 30 to 40 yards away from the ' covered over and plastered down in order to as was placed in it toascertained by a meter which had been fixed specially for the purpose Whilst the gas was being injected the cartridge was prepared

The first experie of tonite--fired without the patent extinguisher--would ignite the gas The gas having been turned on, a uished before the full quantity of gas had gone through the e of 1-1/4 oz tonite was placed in the ” wires to the dynaiven to ”fire” With a tre of the as had exploded The next cartridge (a sie) was prepared with the patent compound First of all a brown paper case of about 2 inches diaes was placed in the centre of it, the intervening space between the charge and-the case being packed with the ”fire-extinguishi+ng coas injected, the protected cartridge was placed inside and fired The result was astonishi+ng, the explosion not being nearly so loud, whilst there was not the least flash of fire ”Protected” and ”unprotected” charges were fired at intervals, gas being turned into the tank on each occasion Charges of tonite varying from 1 to 6 oz were also used with the co, whilst no flash could be seen

~Uses of Collodion-Cotton~--The collodion or soluble gun-cotton is used for a variety of purposes The chief use is, however, for the elatine coelatine is the type It is also very extensively used in the --in fact, very few of thenose or nitrated wood is used instead This, however, is che, viz, nitro- cellulose, the cellulose being derived from the wood fibre It is un-cotton Another use to which it has been applied very extensively, of recent years, is in the raphy for the preparation of the films on the sensitised plates, and many other purposes Dissolved in a solution of two parts ether and one of alcohol, it forms the solution known as collodion, used for a variety of purposes, such as a varnish, as a paint for signals; in surgery, for uniting the edges of wounds

Quite lately, Mr Alfred nobel, the well-known inventor of dynamite, has patented the use of nitro-cellulose, hydro- or oxy-cellulose, as an artificial substitute for indiarubber For this purpose it is dissolved in a suitable non-volatile or slightly volatile ”solvent,” such as nitro- naphthalene, di-nitro-benzene, nitro-toluene, or its hoelatinous consistency to the hardness of ebonite The proportions will vary from about 20 per cent of nitro- cellulose in the finished product, for celluloid, and the ”solvent” chosen will depend on the use to which the rubber substitute is to be put, the liquids giving a more elastic substance, whilst mixtures of solids and liquids h temperatures By means of rollers steam heated, the incorporation may be accomplished without the aid of a volatile liquid, or the nitro-celluloseremoved after ”solution”

It is advisable to use the cellulose nitrated only just enough to render it suitable, in order to reduce the inflammability of the finished product Mr W Allen, MP, of Gateshead, proposed to use celluloid for cartridge cases, and thus to lighten a, for the case will be resolved into gases along with the powder Extractors will also be done aith

~Celluloid~ is an intiun-cotton or collodion-cotton) with camphor, firstthe pyroxyline tothe two substances together, or by dissolving the constituents in an appropriate solvent, eg, alcohol or ether, and evaporating to dryness A combination of the two latter methods, ie, partial solution, with pressure, is now usually adapted The pyroxyline eenerally the tetra- and penta-nitrated cellulose, the hexa-nitrate (gun-cotton) being but seldom used on account of its explosive properties

Care is taken to prevent the for the cellulose in onlynitric acid, or in a warm mixture of nitric and sulphuric acids The paper, either in small pieces or in sheets, is immersed for about twenty-five minutes in a mixture of 2 parts of nitric acid and 5 parts of sulphuric acid, at a temperature of about 30 C, after which the nitrated cellulose is thoroughly washed ater to remove the last traces of free acid, pressed, and whilst still moist, mixed with the camphor

In the process of Trebouillet and De Besancele, the cellulose, which may be in the form of paper, cotton, or linen, is twice nitrated--first in the acid mixture employed in a previous operation; and secondly, in a fresh ravity, and 2 parts concentrated nitric acid containing nitrous acid After each nitration the mass is subjected to pressure, and is then carefully washed ater, to which, at the last, a small quantity of ammonia or caustic soda is added to renation of the pyroxyline with the camphor is effected in a variety of ways

The usual proportion of the constituents is 2 parts pyroxyline and 1 part camphor In Trebouillet and De Besancele's process, 100 parts of pyroxyline are intiether by strong pressure in a hot press, and afterwards dried by exposure to air, desiccated by calcium chloride or sulphuric acid The usual method is, however, to dissolve the camphor in the least possible quantity of alcohol, and sprinkle the solution over the dry pyroxyline, which is then covered with a second layer of pyroxyline, and the whole again treated with the camphor solution, the addition of pyroxyline and ca repeated alternately until the requisite amount of celluloid ether in transparent lumps, is worked for about an hour between cold iron rollers, and then for the saently heated by stea the rollers is then cut away and again pressed, the resulting cake, which is now about 1 c and 30 cly pressed together by hydraulic pressure at a temperature of about 70 for twenty-four hours The thick cakes are once more cut into plates of the desired thickness, and placed in a chaht to fourteen days, whereby they becohly dry, and are readilymoulded while warm under pressure, cut, or turned Occasionally other liquids, eg, ether and wood spirit, are used in place of alcohol as solvents for the camphor

Celluloid readily colours, and can be hly inflammable and not explosive even under pressure, and may be worked under the ha water, and htly with its coree of pressure it has received It is usually 135 It appears to be merely a mixture of its components, since by treatment with appropriate solvents the ca the pyroxyline burns ahile the camphor volatilises

Thecelluloid has veryrecent years, and with this increase of production improved methods ofpapers upon the manufacture of pyroxyline has been published by Mr Walter D Field, of New York, in the _Journal of the A particulars are taken:--

[Footnote A: Vol xv, No 3, 1893; Vol xvi, No 7, 1894; Vol xvi, No

8, 1894 Figs 19, 20, 21, 22, and 23 are taken from Mr Field's paper]

~Selection of the Fibre~--Cotton fibre, wood fibre, and flax fibre in the forenerally used, and give the best results As the fibres differ greatly in their structure, they require differentThe cotton fibre is a flattened hollow ribbon or collapsed cylindrical tube, twisted a number of times, and closed at one end to fore, and runs nearly to the apex of the fibre Its side walls are membraneous, and are readily penetrated by the hest nitration results In the flax fibre the walls are comparatively thick, the central canal small; hence it is to be presumed that the nitration must proceed ives the ives a glutinous collodion, and calico a fluid collodion One of the largest manufacturers of pyroxyline in the States uses the ”Memphis Star” brand of cotton This is an upland cotton, and its fibres are very soft, ht creamy white, and is retained after nitration The staple is short, and the twist inferior to other grades, the straight ribbon-like fila quite numerous This cotton is used carded, but not scoured This brand of cotton contains a large quantity of half and three-quarter ripe fibre, which is extrehout the bulk of the cotton (Monie, Cotton Fibre, 67) Mr Field says, ”This is a significant fact when it is known that from this cotton an extremely soluble pyroxyline can be produced”

Pyroxyline of an inferior grade as regards colour only can be produced from the cotton wastes of the trade TheyPaper made from the pulps of sulphite and sulphate processes is capable of yielding a very soluble pyroxyline It can be nitrated at high teood results Tissue papercut into squares

Mowbray (USP, No 443, 105, 3rd December 1890) says that a pure cotton tissue paper less than 1/500 inch in thickness, thin as it is, takes on a glutinous or colloid surface, and thus requires some thirty minutes to enable the nitration to take place With a thicker paper only the surface would be nitrated He therefore uses a fibre that has been saturated with a solution of nitrate of soda, and afterwards dried slowly, clai that the salt crystallises in the fibre, or enters by the action termed osmose, and opens up the fibre to the action of the acid This process would only be useful when the cotton is to be nitrated at a low teh temperature it would be unnecessary