Part 4 (1/2)

Upon leaving the filter house, where it has been washed and filtered, and has satisfactorily passed the heat test, it is drawn off from the lowest tank in indiarubber buckets, and poured down the conduit leading to the precipitating house, where it is allowed to stand for a day, or soer, in order to allow the little water it still contains to rise to the surface In order to accomplish this, it is sufficient to allow it to stand in covered-in tanks of a conical forh

In h common salt, which of course absorbs the last traces of water It is then of a pale yellow colour, and should be quite clear, and can be drawn off by means of a tap (of vulcanite), fixed at the bottom of the tanks, into rubber buckets, and is ready for use in the preparation of dynaelatine compounds, smokeless powders, &c, such as cordite, ballistite, and many others

Mikolajezak (_Chem Zeit_, 1904, Rep 174) states that he has prepared lycerine, and believes that the latter compound will form a valuable basis for explosives, as it is unfreezable It is stated to be an odourless, unfreezable oil, less sensitive to percussion, friction, and increase of tereater solvent power for collodion-cotton than ordinary nitro-glycerine It can thus be used for the preparation of explosives of high stability, which will lycerine is a solvent for tri-nitro-glycerine, it can therefore be elatine explosives in order to lower the freezing point

~The Waste Acids~--The waste acids frolycerine has been as completely separated as possible, are run down the conduit to the secondary separator, in order to recover the last traces of nitro-glycerine that they contain The coenerally soravity, 17075 at 15 C; sulphuric acid, 672 per cent; nitric acid, 1105 per cent; and water, 217 per cent, with perhaps asquantities of nitro-glycerine, which must be separated, as it is impossible to run this liquid away (unless it can be run into the sea) or to recover the acids by distillation as long as it contains this substance The e circular lead-lined tanks, covered in, and veryapparatus in construction, that is, they contain worh to keep the itate the mixture if necessary The top also should contain a , in order to allow of the interior being seen, and should have a leaden chimney to carry off the fumes which lass tube of 3 or 4 inches in diameter substituted for about a foot of the lead chimney, in order that the man on duty can at any ti fro one reaching to the bottom of the tank, and one to just a few inches below the surface of the liquid

The nitro-glycerine, of course, collects upon the surface, and can be drawn off by a tap placed at a convenient height for the purpose The cover of the tank is generally conical, and is joined to a glass cylinder, which is cemented to the top of this lead cover, and also to the lead chiround glass stopper, through which the nitro-glycerine can be drawn off There will probably never be lycerine at the most, and seldom that It should be taken to the filter house and treated along with another charge The acids themselves may either be run to waste, or better treated by some denitration plant This house probably requires er area, on account of the danger of the decolycerine, which, as it is e quantity of acids and water, is very apt to become hot, and decolobule of nitro-glycerine is floating, surrounded by acids that gradually get hot, gives off nitrous fumes, and perhaps explodes, and thus causes the sudden explosion of the whole The only way to prevent this is for the worke to look at the ther fumes, and if he should notice a rise of temperature or any appearance of red fumes, to turn on the water and air, and stir up the mixture, when probably the temperature will suddenly fall, and the fumes cease to co is either the non-attention of the work of one of the water pipes, by whichits way into the acids, causes a sudden rise of temperature If the latter of these two causes should occur, the water should at once be shut off and the air turned on full, but if it is seen that an explosion is likely to occur, the tank should at once be e tank placed close outside the house, which should be about 4 feet deep, and soh to hold a considerable quantity of water But this last course should only be resorted to as a last extremity, as it is extrelycerine froenerally a bricked and cemented excavation some few yards from the house

It has been proposed to treat these waste acids, containing nitro- glycerine, in Mr M Prentice's nitric acid retort In this case they would be run into the retort, together with nitrate of soda, in a fine strea into contact with the hot mixture already in the retort, would probably be at once decoh not yet tried, promises to be a success Several processes have been used for the denitration of these acids

~Treatment of the Waste Acid from the Manufacture of Nitro-Glycerine and Gun-Cotton~--The colycerine and Gun-cotton Waste Acid

Sulphuric acid 70 per cent 78 per cent

Nitric acid 10 ” 12 ”

Water 20 ” 10 ”

The waste acid froenerally used direct for the e amount of sulphuric acid, and the senerally contains decoradually and without explosion in the retort Nitric acidthen added to the equivalent amount of nitrate of soda Nitric acid is then distilled over and condensed in the usual way Very often, however, the waste acid is added direct to the charge of nitrate without previously eli the nitric acid The treatlycerine is solycerine in this acidthe waste acid to stand for at least twenty- four hours in a big vessel with a conical top, where all the nitro- glycerine which will have separated to the surface is re down process” of Col Nathantrace of nitro-glycerine is separated from the acids in a few hours after the nitration, and any further for about 2 per cent of water to the waste acids, which are kept agitated during the addition The waste acid, now free froanicit into contact with a jet of steah a tower of acid-resisting stoneware (volvic stone), which is closely packed with earthenware, and at the bottom of which is the steam jet Decomposition proceeds as the acid ed and are passed out at the top of the tower through a pipe to a series of condensers and towers, where the nitric acid is collected The nitrous acida hot coases before they pass into the condensers Weak sulphuric acid of sp gr 16 collects in a saucer in which the tower stands, and is then passed through a cooling worm The weak sulphuric acid, now entirely free fror 1842 and 96 per cent H_{2}SO_{4} by any of the well-known processes, eg, Kessler, Webb, Benker, Delplace, &c, and it un-cotton

Two points in the reatest ilycerine used, and the strength and purity of the acids used in the nitration With regard to the first of these, great care should be taken, and a co a preliminary experiards the second, the sulphuric acid should not only be strong (96 per cent), but as free froenerally made at the explosive works where it is used, careas possible (97 per cent

and upwards) This can easily be obtained if the plant designed by Mr Oscar Gutt worked Mr Guttmann's plant for some time, I can testify as to its value and efficiency

[Footnote A: ”The Manufacture of Nitric Acid,” _Jour Soc Chem Ind_, March 1893]

Another form of nitric acid plant, which promises to be of considerable service to the , is the invention of the late Mr Manning Prentice, of Stowh the kindness of Mr Prentice, I visited his works to see the plant in operation It consists of a still, divided into compartments or chambers in such a manner that the fluid may pass continuously fro continuously separated by distillation, the contents of each division vary--the first containing the full proportion of nitric acid, and each succeeding one less of the nitric acid, until from the overflow of the last one the bisulphate of soda floithout any nitric acid The nitrate of soda is placed in weighed quantities in the hopper, whence it passes to the feeder The feeder is a -mill, which receives the streahlythem, delivers them into the still, where, under the influence of heat, they rapidly becoeneous liquid, from which nitric acid continuously distils

Mr Prentice says: ”Initric acid is one of fractional distillation by time, mine is fractional distillation by space” ”Instead of the operation being always at the sa by the successive points of tie for the differences to take place at different points of space, and these differences exist at one and the same points of time” It is possible with this plant to produce the full product of nitric acid of a gravity of 1500, or to obtain the acid of varying strengths from the different still-heads One of these stills, capable of producing about 4 tons of nitric acid per week, weighs less than 2 tons It is clai ofplant Further particulars and illustrations will be found in Mr Prentice's paper (_Journal of the Society of Chemical Industry_, 1894, p 323)

CHAPTER III

_NITRO-CELLULOSE, &c_

Cellulose Properties--Discovery of Gun-Cotton--Properties of Gun-Cotton-- Varieties of Soluble and Insoluble Gun-Cottons--Manufacture of Gun-Cotton-- Dipping and Steeping--Whirling out the Acid--Washi+ng--Boiling--Pulping-- Co--The Waltham Abbey Process--Le Bouchet Process--Granulation of Gun-Cotton--Collodion-Cotton--Manufacture--Acid Mixture used--Cotton used, &c--Nitrated Gun-Cotton--Tonite--Dangers in Manufacture of Gun-Cotton-- Trench's Fire-Extinguishi+ng Compound--Uses of Collodion-Cotton--Celluloid-- Manufacture, &c--Nitro-Starch, Nitro-Jute, and Nitro-Mannite

~The Nitro-Celluloses~--The substance known as cellulose foretable tissues The cellulose of the woody parts of plants was at one tinine, but they are now regarded as identical The forenerally assumed that the molecular formula must be represented by aoften regarded as the minimum The assumption is based on the existence of a penta-nitrate and the insoluble and colloidal nature of cellulose Green (_Zeit Farb Text Ind_, 1904, 3, 97) considers these reasons insufficient, and prefers to ele formula C_{6}H_{10}O_{5} Cellulose can be extracted in the pure state, fro the with dilute hydrochloric acid, water, alcohol, and ether in succession, until none of these solvents re more Fine paper or cotton wool yield very nearly pure cellulose by similar treatment

Cellulose is a colourless, transparent mass, absolutely insoluble in water, alcohol, or ether It is, however, soluble in a solution of cuprammoniac solution, prepared from basic carbonate or hydrate of copper and aqueous aravity of cellulose is 125 to 145

According to Schulze, its elee numbers:--

Carbon 440 per cent 442 per cent

Hydrogen 63 ” 64 ”

Oxygen 497 ” 494 ”

These numbers represent the composition of the ash free cellulose Nearly all forms of cellulose, however, contain a small proportion of anic portion of the fibre or tissue is of such a nature that the ash left on ignition preserves the for point of certain young shoots that the cellulose tissue is free from mineral constituents”