Part 3 (1/2)

It has been proposed to free nitric acid froh it, and thus driving the gases in solution out The acid was contained in a closed lead tank, fro fumes were conducted into the chimney shaft, and on the bottom of which was a lead pipe, bent in the forh which the compressed air was made to pass; but the process was not found to be of a very satisfactory nature, and it is certainly better not to allow the formation of these compounds in the manufacture of the acid in the first instance Another plan, however, is to heat the acid gently, and thus drive out the nitrous gases Both processes involve loss of nitric acid

Having obtained nitric and sulphuric acids as pure as possible, the next operation is tothe carboys in which the acids are generally stored before the acids are drawn off into thehts constantly attached to theh off as many carboys of acid as s, and subtract the weights of the carboys The two acids should, after being weighed, be poured into a tank andorhouse in the danger area Thecast-iron tank, of either an egg shape, or a cylinder with a round end If of the former shape, it would lie on its side, and upon the surface of the ground, and would have a ly bolted down; but if of the latter shape, the lid, of course, is upon the top, and the round In either case, the principle is the saoes to the bottom, and another just inside to convey the co away as the pressure is put on, just as blowing down one tube of an ordinary wash- bottle forces the water up the other tube to the jet The pressure necessarily will, of course, vary iht to which the acid has to be raised and the distance to be traversed

The er area, and to a level higher than the position of the nitrating house, should, before being used, be allowed to cool, and leaden tanks of sufficient capacity to hold at least enough acid for four or five nitrations should be placed in a wooden house upon a level at least 6 or 7 feet above the nitrating house

In this house also should be a s, when filled to a certain h of the mixed acids for one nitration The object of this tank is, that as soon as the e knows that the last nitration is finished, he refills this sh of the mixed acids), and allows its contents to flon into the nitrating house and into the nitrator, ready for the next nitration

The nitration is usually conducted in a vessel constructed of lead, some 4 feet wide at the bottoh The size, of course, depends upon the volue it is intended to nitrate at one operation, but it is always better that the tank should be only two-thirds full A good charge is 16 cwt of the mixed acids, in the proportion of three to five; that is, 6 cwt of nitric acid, and 10 cwt of sulphuric acid, and 247 lbs of glycerine

Upon reference to the equation showing the forlycerine, it will be seen that for every 1 lb of glycerine 247 lbs of nitro- glycerine should be furnished,[A] but in practice the yield is only a little over 2 lbs, the loss being accounted for by the unavoidable forlycerine (thewaters The lead tank (Fig 5) is generally cased in ork, with a platfor to stand upon, and whence to work the various taps The top of the tank is closed in with a doh which the progress of the nitrating operation can be watched From the top of this doh the roof of the building It serves as a chi the nitration The interior of this tank contains at least three concentric spirals of at least 1-inch lead pipe, through which water can beAnother lead pipe is carried through the dome of the tank, as far as the bottoh this pipe, which is pierced with small holes, about 1 inch apart, compressed air is forced at a pressure of about 60 lbs in order to keep the liquids in a state of constant agitation during the whole period of nitration There must also be a rather wide pipe, of say 2 inches internal diah the dome of the tank, which will serve to carry the mixed acid to be used in the operation into the tank

There is still another pipe to go through the dolycerine into the tank This need not be a large bore pipe, as the glycerine is generally added to the mixed acids in a thin stream (an injector is often used)

[Footnote A: Thus if 92 lbs glycerine give 227 lbs nitro-glycerine, (277 x 1)/92 = 247 lbs]

[Illustration: FIG 5--TOP OF NITRATOR _A_, Fu; _C_, Acid Mixture Pipe; _E_, Compressed Air; _G_, Glycerine Pipe and Funnel; _T_, Thermometer; _W_, Window]

Before the apparatus is ready for use, it requires to have two ther one to reach to the bottoh to dip under the surface of the acids When the tank contains its charge, the forives the temperature of the bottolycerine should be contained in a small cistern, fixed in so house, and should have a pipe let in flush with the botto apparatus It must of course be provided with a tap or stop-cock, which should be placed just above the point where the pipe goes through the lead dolycerine used ood plan, but it is essential that the graduations should be clearly visible to the operator upon the platfore tap made of earthenware (and covered with lead) is fixed in the side of the nitrating tank just above the bottoe after nitration This should be so arranged that the charge may be at option run down the conduit to the next house or discharged into a drowning tank, which may so tank is generally so and several feet deep, lined with ce

The apparatus having received a charge of h the pipes coiled inside the tank, and a slight pressure of compressed air is turned on,[A] toThe nitration should not be coister a telycerine tap is then partially opened, and the glycerine slowly admitted, and the compressed air turned on full, until the contents of the apparatus are in a state of very brisk agitation A pressure of about 40 lbs is about the lycerine and 16 cwt of acids are in the tank) If the glycerine tube is fitted with an injector, it may be turned on almost at once The nitration will take about thirty minutes to complete, but the compressed air and water should be kept on for an additional ten lycerine to nitrate The temperature should be kept as low as possible (not above 18 C)

[Footnote A: At the Halton Factory, Germany, cylinders of compressed carbon dioxide are connected with the air pipes so that in the event of a failure of the air supply the stirring can be continued with this gas if necessary]

The chief points to attend to during the progress of the nitration are--

1 The teistered by the two theriven off (as seen through the littlein the dome of the apparatus)

3 The pressure of the coe fixed upon the air pipe just before it enters the apparatus

4 The gauge showing the quantity of glycerine used The temperature, as shown by either of the two therher than 25 C

If it rises lycerine should be at once shut off, and the pressure of air increased for some few minutes until the teiven off

The nitration being finished, the large earthenware tap at the bottoe allowed to floay down the conduit to the next building, ie, to the separator

The nitrating house is best built of wood, and should have a close-boarded floor, which should be kept scrupulously clean, and free froe should be kept in the house in order that the workman may at once clean up any mess that may be made, and a small broom should be handy, in order that any sand, &c, ood plan for the nitrator to keep a book in which he records the ti and at the finish, the tie, as this enables the forees have been nitrated, and gives hi Edward Liebert has devised an ilycerine He adds a the operation of nitrating, which he clai to the equation--

(NH_{4})_{2}SO_{4} + 2HNO_{3} = H_{2}SO_{4} + 2N_{2} + 4H_{2}O

I am not aware that this modification of the process of nitration is in use at the present tilycerine, upon leaving the nitrating house, floay down the conduit, either made of rubber pipes, or better still, of ork, lined with lead and covered with lidsthem at any point the condition of the conduit can be exareatest importance, and the conduit requires to be frequently washed out and the sulphate of lead relycerine, and should therefore be burnt in soazine, as it frequently explodes with considerable violence

[Illustration: FIG 6--SMALL NITRATOR _N_, Tap for Discharging; _P_, Water Pipes; _T_, Thermometer; _W_, Windows; _P'_, Glycerine Pipe]

In works where the lycerine is of secondary i only perhaps 10 per cent of nitroglycerine is lycerine are nitrated at one ti apparatus than the one that has been already described will be probably all that is required In this case the for 6 will be found very satisfactory It should be made of stout lead (all lead used for tanks, &c, must be ”chemical lead”), and may be made to hold 50 or 100 lbs as found most convenient This nitrator can very well be placed in the same house as the separator; in fact, where such a slycerine is required, the whole series of operations, nitrating, separation, and washi+ng, &c,It will of course be necessary to place the nitrator on a higher level than the separator, but this can easily be done by having platfor perforhest The construction of this nitrator is essentially the sa soh, and one thermometer It will not be necessary to cover this form in ork

~The Nathan Nitrator~[A]--This nitrator is the patent of Lt Col FL