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_?
[Illustration: Fig. 2.]
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.
[Illustration: Fig. 3.]
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.
[Illustration: Fig. 4.]
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.
[Illustration: Fig. 5.]
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]]