Part 10 (1/2)

Ordinary dynalycerine and 25 per cent of kieselguhr The guhr as imported (Messrs A Haake & Co are the chief ianica weighed quantity in a platinu, and the organic ly over a Bunsen burner Before the guhr can be used for et rid of uhr should absorb four tilycerine, and should then form a comparatively dry mixture It should be pale pink, red brown, or white The pink is generally preferred, and it should be as free as possible frorit of all kinds, quartz particles, &c, and should have a ser and thue quantity of diato was the analysis of a dried sanesia, 210; oxide of iron and aluanic enerally dried in a reverberatory muffle furnace It is spread out on the bottom to the thickness of 3 or 4 inches, and should every now and then be turned over and raked about with an iron rabble or hoe The teuhr red hot, or the organicwill depend of course upon the quality of the guhr being operated upon Those containing a high percentage of water and organic er than those that do not A sauhr should not contain ether

After the guhr is dry it requires to be sifted and crushed The crushi+ng is done by passing it between iron rollers fixed at the botto at a moderate speed Beneath the rollers a fine sieve should be placed, through which the guhrbeen dried, crushed, and sifted, should be packed away in bags, and care should be taken that it does not again absorbabove about five-tenths per cent of water it will cause the dynauhr thus prepared is taken up to the danger area, and lycerine used should be quite free fro for a day or two in the precipitating house The guhr and nitro-glycerine are mixed in lead tanks (about 1-1/2 foot deep, and 2 to 3 feet long), in the proportions of 75 of the nitro-glycerine to 25 of the guhr, unless the guhr is found to be too absorbent, which will cause the dynamite to be too dry and to crumble In this case a small quantity of bariuuhr This will lessen its absorbing powers, or a highly absorptive sauhr may be mixed with one of less absorptive power, in the proportions found by experiment to be the best suited to make a fairlyitself is generally perforuhr is weighed, placed in a tank, and the nitro- glycerine poured on to it The nitro-glycerine hed out in indiarubber buckets The whole is then mixed by hand, and well rubbed between the hands, and afterwards passed through a sieve At this stage the dynamite should be dry and powdery, and of a unifores, and should be taken over to the cartridge huts These are sle cartridge irls--one to work the press, and two to wrap up the cartridges The cartridge press consists of a short cylinder of the diae that it is intended to nu worked by a lever Round the upper edge of the cylinder is fastened a canvas bag, into which the powdery dyna piston forces the dynamite down the cylinder and out of the open end, where the coths The whole ainst the wall of the building The two girls, who sit at tables placed on each side of the press, wrap the cartridges in parches are collected by boys every tenroom, where they are packed in 5-lb

cardboard boxes, which are then further packed in deal boxes lined with indiarubber, and fastened down air tight The wooden lids are then nailed doith brass or zinc nails, and a label pasted on the outside giving the weight and description of the contents The boxes should then be reazines It is well to take a certain nu house at different ti the day, say three or four samples, and to test thee, about 1 inch long, should be placed under a glass shade, together ater (a large desiccator, in fact), and left for soood dynans of exudation, even after weeks[A]

[Footnote A: For analysis of dynamite, see chapter on ”analysis,” and author's article in _Cheuhr Dynahs 76 lbs 4 oz The specific gravity of 75 per cent dynarey colour, and rather greasy to the touch It is lycerine, but explodes occasionally with the shock of a rifle bullet, or when struck The addition of a few per cent of camphor will considerably diminish its explosive qualities to such an extent that it can befulrates dynareat caution is necessary in using it in wet places It freezes at about 40 Fahr (4 C), and re that point When frozen, it is coent, andthe cartridges in a war pan, which consists of a tin can, with double sides and bottom, into which hot water (130 Fahr) can be poured The dynamite will require to be left in for some considerable time before it becomes soft On no account must it be placed on a hot stove or near a fire, as many serious accidents have occurred in this way

Frozen dynamite is a hard r lycerine, which is much more sensitive to shock, and if accidentally struck with an iron tool, e with a knife Raerous, but wasteful, to use dynamite when in a frozen state

Dynamite explodes at a temperature of 360 Fahr, and is very sensitive to friction when hot In hot countries it should never be exposed to the rays of the sun It should, however, not be kept in a damp or ht, if direct, can cause a slow decomposition, as with all nitro and nitric co it, at least when operating in the open air

Dynalycerine, appears to keep indefinitely Sodium or calcium carbonate to the extent of 1 per cent is often added to dyna neutral If it has coe, however, it rapidly becomes acid, and sometimes explodes spontaneously, especially if contained in resisting envelopes

Nevertheless, neutral and well-azine without loss of its explosive force If water is brought into contact with it, the nitro-glycerine is gradually displaced frouhr) This action tends to render all wet dynaerous

It has been observed that a dynamite made ood sawdust can be moistened and then dried without marked alteration, and from 15 to 20 per cent of waterit of the power of exploding by strong detonator (this is siun-cotton) It is, however, rendered ard to the power of No 1 dynaive the relative value of No 1 dynalycerine, 14 The heat liberated by the sudden explosion of dynamite is the saht of nitro-glycerine contained in the en, and oxygen

[Footnote A: Berthelot, ”Explosives and their Power”]

The ”explosive wave” (of Berthelot) for dynamite is about 5,000 e a foot long would only occupy 1/24000 part of a second, while a ton of dynaes about 7/8 diath, would be exploded in one-quarter of a second by detonating a cartridge at either end[A] Mr C Napier Hake, FIC, the Inspector of Explosives for the Victorian Government, in his paper, ”Notes on Explosives,” says: ”The theoretical efficiency of an explosive cannot in practice be realised in useful work for several reasons, as for instance in blasting rock--

”1 Incoes induced in surroundingof the as through the blast-hole and the fissures caused by the explosion

”The useful work consists partly in displacing the shattered masses The proportion of useful work obtainable has been variously estimated at from 14 to 33 per cent of the theoretical maximum potential”

[Footnote A: CN Hake, ”Notes on Explosives,” _Jour Soc Che the various forms of dynamite that are manufactured is carbo- dynamite, the invention of Messrs Walter F Reid and WD Borland The base is nitro-glycerine, and the absorbent is carbon in the form of burnt cork It is as cheap as ordinary dyna that 90 per cent of the lycerine, and the absorbent itself is highly combustible It is also claimed that if this dynamite becomes wet, no exudation takes place

Atlas powder is a dynamite, chiefly manufactured in America at the Repanno Chelycerine, wood-pulp, nitrate of soda, and carbonate of es committed in London, by the so-called ”dynamiters” Different varieties contain frolycerine

The Rhenish dynamite, considerably used in the mines of Cornwall, is composed of 70 parts of a solution of 2 to 3 per cent of naphthalene in nitro-glycerine, 3 parts of chalk, 7 parts of sulphate of bariu largely given up in favour of gelatine explosives The late Colonel Cundill, in his ”Dictionary of Explosives,”

gives a list of about 125 kinds of dyna the best known after the ordinary No 1 dynamite are forcite, aiant powder, and the various explosive gelatines They all contain nitro- glycerine, mixed with a variety of other substances, such as absorbent earths, wood-pulp, nitro-cotton, carbon in some form or other, nitro- benzol, paraffin, sulphur, nitrates, or chlorates, &c &c

~Blasting Gelatine and Gelatine Dynaelatine explosives chiefly in use are known under the nanite They all consist of the variety of nitro- cellulose known as collodion-cotton, ie, a lycerine, and made up with various proportions of wood-pulp, and soun-cotton contains too little oxygen for colycerine an excess, a mixture of the two substances is very beneficial

Blasting gelatine consists of collodion-cotton and nitro-glycerine without any other substance, and was patented by Mr Alfred nobel in 1875 It is a clear, seravity of 15 to 155, slightly elastic, reseenerally consists of 92 per cent to 93 per cent of nitro-glycerine, and 7 to 8 per cent of nitro-cotton The cotton fro is the analysis of a saelatine:-

Soluble cotton 99118 per cent

Gun-cotton 0642 ”