Chapter XVIII: Part X: Laboratory Stores

1. What is a _fuze_?

The contrivance by which fire is communicated to the charge in a shell. It consists, essentially, of a highly inflammable composition inclosed in a wood, metal, or paper-case.

2. What fuzes are used in the U. S. service?

Wooden, paper, the Bormann and the United States sea-coast fuzes.

3. Describe the _wooden fuze_.

It consists of a conical plug of wood, of the proper size for the fuze-hole of the shell with which it is to be fired. The axis of this plug is bored out cylindrically, from the large down to within a short distance of the small end, which is left solid. At the large end a cup is hollowed out, and the outside of the plug is divided into inches and parts, generally tenths, commencing at the bottom of the cup. The cylindrical space is filled with composition, pounded hard, and as regularly as possible, and the cup filled with mealed powder moistened with whisky or alcohol. The rate of burning is determined by experiment, and marked on a water proof cap, which is tied over the cup. Knowing the time any shell is to occupy in its flight, the fuze is cut off with a saw at the proper division, and firmly set in the fuze-hole with a fuze-set and mallet. Say the fuze burns 5" to the inch. If a shell be 10" in reaching the mark two inches of fuze will burst it as it strikes. If it takes 8" to reach the mark, 1⁶/₁₀ in. will be cut off, &c.

[Sidenote: 110]]

4. What is the disadvantage of this fuze?

Its irregularity, it being very difficult to pound the composition so that equal lengths will burn in equal times. The shell may either burst too soon, and a great part of its effect be lost; or it may burst after burying itself in the ground; or it may burst after passing the proper point. This irregularity of burning is common to all fuzes where the composition is driven in successive layers in a column which burns in the same direction.

5. What is the composition for Mortar fuzes?

===+======+========+=======+=============+======================
No.|Nitre.|Sulphur.|Mealed | Time of | Remarks.
| | |Powder.|burning 1 in.|
---+------+--------+-------+-------------+----------------------
1 | 2 | 1 | 3 | 3.8 sec. |For Siege Mortars.
2 | 2 | 1 | 2¼ | 5. “ | “ Sea-Coast “
3 | — | — | 1 | 2.2 “ | “ 8-in. Howitzers.
---+------+--------+-------+-------------+----------------------

6. Is the wooden fuze used?

Yes, for Mortars.

7. Are these fuzes always cut before being inserted in the shell?

Generally they are; but they are sometimes _bored_ through at the proper positions instead of being sawed.

[Sidenote: 111]]

8. Are they ever cut obliquely?

Yes, when the fuze is so long as to render it likely that it will reach the bottom of the shell; for by cutting it perpendicular to the axis, the whole base of the wood might be driven in contact with the bottom of the shell, and prevent the lighted composition from setting fire to the bursting charge.

9. Describe the _paper-fuze_.

It consists of a conical paper-case, containing the composition, whose rate of burning is shown by the color of the case, as follows:

Black, burns 2" to the inch
Red, “ 3" “
Green, “ 4" “
Yellow, “ 5" “

Each fuze is made two inches long, and the yellow consequently burns 10". For any shorter time, the fuze is cut with a sharp knife. With this fuze is used a fuze-plug having a conical opening, which is reamed out to fit the paper-case when the shell is loaded, and the fuze is then pressed in with the thumb.

10. What is the great advantage of this fuze?

Its simplicity, and the little trouble required to place it in the shell, which renders unnecessary the numerous and complicated instruments such as saws, fuze-setter, and extractor, files, &c., which were formerly used in field artillery.

11. What is the composition of paper fuzes made of?

+==========+===========+==========+
| | Mealed | Sulphur. |
| | Powder. | |
+----------+-----------+----------+
| Black, | 1 | 0 |
| Red, | 8 | 3 |
| Green, | 8 | 3.5 |
| Yellow, | 8 | 4.0 |
+----------+-----------+----------+

[Sidenote: 112]]

12. Describe the _Belgian_ or _Bormann fuze_?

The fuze-case is made of metal (a composition of lead and tin), and consists Fig. 2, first, of a short cylinder, having at one end a horse-shoe shaped indentation; _one_ end only of which communicates with the magazine of the fuze placed in the centre.

This horse-shoe indentation extends nearly to the other end of the cylinder, a thin layer of the metal only intervening. This is graduated on the outside into equal parts representing seconds and quarter seconds (see Fig. 4). In the bottom of this channel a smooth layer of the composition is placed, with a piece of wick or yarn underneath it. On this is placed a piece of metal, the cross section of which is wedge shaped (see Fig. 3); and this, by machinery, is pressed down upon the composition, sealing it hermetically. The cylindrical opening represented at _a_ Fig. 2, is filled with fine powder and covered with a sheet of tin, which is soldered, closing the magazine from the external air.

[Sidenote: 113]]

Before using the fuze, several holes are punched through this sheet of tin, to allow the flame to enter the shell. On the side of the fuze the thread of a screw is cut which fits into one cut on the inside of the fuze-hole, and the fuze is screwed into the shell with a wrench.

The thin layer of metal over the composition is cut through with a gouge or chisel, or even a pen-knife, at the interval marked with the number of seconds which we wish the fuze to burn. To prevent the metal of this fuze, which is soft, from being driven into the shell by the explosive force of the charge, a circular piece of iron, with a hole through its centre, and the thread of a screw on the outside Fig. 5 is screwed into the fuze-hole before the fuze is inserted.

13. To what kind of artillery has this fuze been confined?

Principally to light artillery, in firing shells and particularly spherical case, where regularity and certainty are essential requisites.

[Sidenote: 114]]

14. Mention one important advantage of this fuze.

The shells can be loaded, all ready for use, and remain so any length of time, perfectly safe from explosion, as the fuze can be screwed into its place, and the composition never exposed to external fire until the metal is cut through.

15. What is the only operation under fire required?

To gouge through the metal at the proper point, with any kind of chisel, knife, or other instrument.

16. Describe the United States sea-coast fuze.

In the United States, a bronze fuze-plug has been adopted for heavy shells instead of the wooden one. It fits the eye in the same way, and is retained by friction.

It having been found that ricochets, especially over water, were apt to extinguish these fuzes, a safety cap and primer combined have been adopted in the navy. A recess in the top is filled with priming composition and covered, until the fuze is required for use, with a leaden disk which fits accurately the opening. A crooked passage filled with priming, conveys the fire to the fuze composition beneath, and prevents water from being forced in in sufficient quantity to extinguish the fuze.

17. When are paper fuzes for field shells and spherical case inserted?

At the moment of loading the gun, and into wooden _fuze-plugs_ previously driven into the shell.

18. What is a _port-fire_?

It consists of a small paper-case filled with a highly inflammable but slow burning composition, the flame of which is very intense and penetrating, and cannot be extinguished by water.

[Sidenote: 115]]

19. What is it used for?

Principally as an incendiary material in loading shells, and for communicating fire to the priming of guns when proving them.

20. What does port-fire composition consist of?

Of nitre, sulphur, and mealed powder, in different proportions. One kind is composed of

Nitre, 65 parts.
Sulphur, 22.5 “
Mealed powder, 12.5 “

A port-fire case, eighteen inches in length filled with this composition, burns ten minutes.

21. What are _priming-tubes_, and their use?

Small pipes having a cap at one end, and filled with a composition for firing cannon.

22. What tube is in general use in our service?

The friction primer.

23. Describe it.

It consists of a short tube of metal inserted into a hole near the top of a longer tube, and soldered in that position. The short tube, is lined with a composition made by mixing together two parts of chlorate of potassa and one of sulphurate of antimony, moistened with gum water. A serrated wire passes through the short tube and a hole opposite to it in the side of the long one, the open end of the short tube being compressed with nippers, and the wire at the end of the serrated part doubled under to prevent any displacement. The other end of the wire is doubled and twisted by machinery. The long tube is filled with musket powder, its upper end being closed with shellac-varnish, and its lower with shoemakers-wax.

[Sidenote: 116]]

24. What advantage does the friction tube possess?

It gives an enemy at night no clue to the position of your piece, as does the lighted port-fire, or slow-match.

25. What is _slow-match_?

A slow burning match prepared from hemp or flax slightly twisted, soaked in a strong lye, or in water holding in solution sugar of lead. Cotton rope well twisted, forms a good match without any preparation.

26. How long does slow-match prepared from hemp or flax burn?

Four to five inches to the hour.

27. What is the use of slow-match?

It is used principally for the purpose of retaining fire in the shape of a hard-pointed coal, to be used in firing cannon, fire-works, &c. It was formerly used in field batteries for lighting the port fires with which the pieces were discharged; but both are now entirely superseded by the friction tube.

28. What is quick-match?

It is a match made of threads of cotton, or cotton wick, steeped in gummed brandy or whisky, then soaked in a paste of mealed powder and gummed spirits, and afterwards strewed over with mealed powder.

29. How long does it burn?

One yard burns in the open air thirteen seconds.

30. What is the use of quick-match?

To fire stone and heavy mortars, and sometimes in proving pieces. It is extensively used in priming all kinds of fire-works, such as fire and light balls, carcasses, rockets, priming-tubes, &c., and in conveying fire very rapidly from one portion of a piece of fire-work to another.

[Sidenote: 117]]

31. When used for discharging cannon, how is the quick-match set fire to?

By a slow match, port-fire, or any other convenient material.

32. When used to prime carcases, &c., how is it set on fire?

By the flame from the piece.

33. What is _Valenciennes_ composition?

A compound of 50 parts of nitre, 28 of sulphur, 18 of antimony, and 6 of rosin.

34. What is its use?

As an incendiary composition, in charging shells for the purpose of increasing their destructive property, by setting fire to buildings, shipping, &c.

[Sidenote: 118]]