the dark, in bad air, with constant danger of caving earth, suffocation
by noxious gases, destruction of men and galleries by intentional
explosions of hostile mines or accidental ones of our own, in addition
to the usual dangers and difficulties of opening and supplying the
mines under the close fire of the enemy.
These considerations necessitate the rejection of all complicated
systems in the attack, and in the work carried on by the defence during
the siege.
Ignorance of the point to be selected for attack, and the great expense
of permanent countermines, also require those prepared beforehand by
the defence to conform to simple and economical systems.
For this reason it is not necessary to give in detail the systems
proposed by the older writers. They are described in most of the
extended treatises on military engineering.
=77. The Attack.=--The object of the attack is to advance his
galleries in the most rapid manner possible, with the best available
system of ventilation, and to place his mines in such position as to
break up the galleries and destroy the men, materiel, and works of the
defence, both above and below ground; or to form connecting craters
which may be occupied and converted into parallels, trenches, etc.
=78.= To accomplish this, when no natural ravine exists, a deep
trench or “_lodgment_” is made, usually connecting the entrances of all
the galleries and serving as a communication between them, and as a
depot for such supplies as must always be at hand.
From this lodgment the galleries are started by a shaft, blinded
descent, or mining-gallery; the method depending upon the depth to be
reached and the thickness of cover required.
The entrance of each gallery is protected from horizontal and vertical
fire, and from splinters, by a bomb-proof cover and traverses of
sufficient thickness and strength.
The galleries are generally driven in lines nearly parallel, and at
such distance apart that the hostile miners working at any point
between them will be heard, either from the main galleries or from
returns called “_listening-galleries_” or “_listeners_.”[20]
Depending upon the depth at which they are placed and other
circumstances arising in different cases, the main galleries in various
sieges have been placed at distances apart varying from about 8 to 30
yards.
These galleries are connected at intervals by “_transverse galleries_”
or “_transversals_,” which assist the ventilation very much and give
additional communication between them.
Branches for placing mines are driven in prolongation of the gallery
or obliquely to the right or left, and, when the gallery is at a low
level, inclining upward so as to shorten the line of least resistance,
economize powder, and diminish the injury to the gallery and branches,
resulting from the explosion of the mine.
=79.= When the hostile miners come within striking distance of
each other, each strives to run his galleries directly toward the
other in order to avoid exposing its flank to the hostile mine; thus
diminishing as much as possible the injury resulting from its explosion.
=80.= The mines of the attack are generally overcharged in order
to do the greatest possible injury to the mines of the defence, and to
open large craters, but undercharged mines and camouflets are also used
at times.
=81. The Defence.=--The object of the defence is to retard or stop
the advance of the attack, by the destruction of his mines and miners,
without forming craters which will assist him in making his parallels
and approaches.
=82.= For this purpose his galleries must satisfy nearly the
same conditions as those of the attack. They usually start out from
the counter-scarp gallery or from a parallel gallery a little in
advance of it, and extend to a greater or less distance from the work,
according to the time and expense allowable for their construction.
For permanent works they are frequently prepared in time of peace, and
lined with masonry. It is particularly for this class of countermines
that many elaborate systems have been designed for completely covering
the ground, and for throwing up the same earth several times by mines
placed at different depths and exploded in succession. For reasons
previously given, these cannot be recommended.
=83.= A simple system of galleries placed as far below the
surface as practicable, parallel or slightly diverging, connected
when necessary by transversals whose lines prolonged pass inside the
enceintes, and with branches fulfilling the same conditions driven out
for listening-galleries, will, under the direction of an energetic
officer, fulfil the conditions of defence as well, probably, as any
that can be devised.
The branches leading to mine-chambers can be driven out from the main
galleries, transversals, or listeners, as may be desired; and if the
hostile miners obtain possession of any part of the system and blow it
up, the lines of craters formed will be so swept by the fire of the
work that they can hardly be occupied by the enemy.
=84.= As a rule, the mines of the defence will be undercharged or
camouflets, to avoid the formation of exterior craters, but the rule is
not without exceptions.
=85. Shaft Mines=, mines placed in vertical shafts, are used
by both attack and defence for destroying galleries, etc., in their
vicinity. By the attack they are usually placed in craters already
formed, or in other places protected from hostile fire. A shaft is sunk
rapidly, generally “à la Boule,” heavily “overcharged,” filled up with
earth, and fired.
The defence may use the same method or may sometimes prepare them
beforehand, tamping them and leaving a tubular opening through the
tamping for loading and firing them.
MINE TACTICS.
=86.= The tactics of mine warfare result directly from the
consideration above given. The special details of attack and defence
vary in each particular case. The reports of mining operations in
different sieges[21] supply precedents and give suggestions for future
operations of a like character.
=87. Todleben’s Rules.=--The general principles of mine tactics
have been laid down by General Todleben from his experiences at
Sebastopol (in Royal Engineers Occasional Papers, vol. i., 1877). They
may be summarized as follows:
=88. The Attack.=--The besieger should advance by several
galleries, securing those on the flank by listeners. He must be active
and persistent, as the enemy will use every available moment to develop
his countermines. When he receives the first camouflet of the defence
he must hasten to fire his overcharged mines in the uninjured branches,
in order to destroy the hostile countermines. He will generally suffer
losses more or less heavy from this epoch forward, but must submit to
them; since too much circumspection and delay will almost always result
in complete failure.
Before firing the overcharged mines he must have everything in
readiness to occupy and intrench himself in the craters formed; to open
communication from the trenches to the craters either by sap or by
forming a line of connecting craters; and for constructing shelters for
the party occupying the craters and holding them against the sorties of
the defence.
After occupying the craters, he should drive forward his galleries from
them at once, unless the besieged has anticipated him and surrounded
the craters with branches--which may be assumed to be the case if any
delay has occurred in occupying it. In this case he should sink shafts
à la Boule, heavily overcharged, and fire them, and immediately occupy
the new crater and push out from it; and thus progress as rapidly as
possible, by constantly placing and firing overcharged mines, whose
craters will, with little alteration, form both communications and
parallels.
When the fire of the defence upon the crater is so severe that a deep
shaft cannot well be sunk, a shallower one with correspondingly small
charge is first sunk and fired, and a deeper one is sunk from the
crater thus formed.
The overcharged mines should be well tamped when time permits. If
not well tamped the charge should be increased (_or high explosives
used._--J. M.).
=89. The Defence.=--The defence should push out his galleries as
far as possible and at the earliest practicable date, connecting them
by transversals for ventilation, and holding them at a level below any
likely to be reached by the attack.
When near the enemy, he should stop work several times a day and listen
for sounds from the hostile miners which will locate their position.
Hearing the sound of the enemy’s miner, he may work toward him
noiselessly, or prepare and charge a chamber and await the approach
of the miner toward it, listening at the point where the hose trough
(_tube for fuse wires._--J. M.) comes through the tamping until the
enemy is near enough to justify firing. Judgment as to distances must
be formed from practice obtained while driving the countermines.
To avoid forming craters on the surface, and to do the greatest
possible damage to the besieger’s works, the besieged should not fire
his mine until the enemy’s distance from it is less than the line of
least resistance reckoned toward the surface.
When this condition is fulfilled, he may give to his camouflet a charge
of from 3/10 to 4/10 the charge for a common mine placed at the same
depth, since the charge will produce its principal effect upon the
enemy’s gallery, and but little upon the surface.
Special care must be exercised by the defence to avoid premature
explosions, since a mine fired at too great range damages only his own
branch, and may make a crater; thus working directly to the advantage
of the attack, who may prepare an overcharged mine or sink a shaft à la
Boule in the crater thus made.
As successive explosions of necessity damage the branch in use, to
avoid falling back, another one should be prepared as a reserve before
the first is disabled, and at a little distance from it.
After the attack has fired his overcharged mine, the defence, by a
strong fire of canister, musketry, etc., should prevent him from
occupying the craters, and if he takes possession, should drive him
out by a continuous mortar fire, keeping him from completing his
communications by fire from guns.
The defence should push forward branches and establish himself under
the slope of the craters, in front and on both flanks, and by exploding
camouflets prevent the attack from driving galleries or sinking shafts
à la Boule.
When the nature of the soil admits, many of the camouflets will be
placed by boring. Should the defensive measures above and below ground
not debar the enemy from establishing himself in the crater, the
defence may establish overcharged mines immediately in its front, with
a view to destroying the advancing galleries of the attack, blowing up
the men and their lodgment in the crater, and opening up the latter to
the fire of the work.
Shafts à la Boule being very dangerous for the countermines, the
defence should do his best to prevent their use, by artillery and
musketry fire above ground, and by camouflets placed by boring under
ground. In addition, he must take advantage of every favorable
opportunity to delay the progress of the attack by sorties from the
works.
=90. Remark.=--In underground warfare the besieger has a decided
advantage, but the besieged, by a cool consideration in handling his
mines, and by persistently holding back the attack, foot by foot, may
very greatly retard it, or even cause such losses and delays as to lead
to its being abandoned.
BREACHING BY MINES.
=91.= The attack having reached the scarp of the work, mines are
prepared for breaching the counter-scarp and scarp.
Experience shows that the charges are best located in rear of the
counterforts when they exist, or at equal intervals along plain walls.
The charge should not be placed immediately in contact with the
masonry, but in the earth behind it, and at a depth below the top of
the wall equal at least to 1½ the L. L. R., measured to the face of the
wall.
The charge should be estimated by the rules already given, and
increased by 20 to 30 per cent, so as not only to throw down the walls,
but also to break up the earth and form a practicable breach.
=92.= The galleries for placing the chambers behind the
counterscarp are branches from the gallery of descent into the ditch;
those behind the scarp may branch out from a gallery driven under the
ditch, when water or rock do not forbid, or from a gallery driven
through the scarp wall after crossing the ditch by sap or by a bridge.
=93.= To start the gallery through the scarp wall, a miner is
“_attached_” to the wall by protecting him from fire along the ditch,
from sorties, and from loaded shells, etc., rolling down upon him from
the parapet by suitable traverses and splinter-proof.
This operation is of course very dangerous, and is generally impossible
unless the fire of the defence along the ditch is previously silenced.
To expedite the work of the miner a gun is sometimes brought down
through the gallery, and the face of the wall is shattered by its fire
before the miner is “=attached=.”
CHAPTER IV.
BLASTING AND DEMOLITIONS.
BLASTING.
=94. Blasts= are small mines used generally for breaking up rocks,
or masonry in demolitions.
=95.= Holes for placing the charges are drilled usually with
_drill-bars_ or _churn-drills_, known also as _jumpers_.
These are steel bars sharpened to a chisel edge. The _drill-bar_ is
usually held by one man and struck with a hammer by another; it is
turned slightly after each blow in order to make a round hole.
For small holes the driller holds the drill in one hand and strikes
with the other.
The _churn-drill_ is a longer bar, generally sharpened at both ends
and enlarged in the middle. It is used for drilling vertical holes by
raising and dropping it in the holes, turning it slightly after each
blow.
=96.= The _charge_ may be gunpowder or high explosive. If the
former, it must be thoroughly tamped. If the latter, tamping will
greatly increase its effect; but it is in some cases preferable to
obtain the desired effect by increasing the charge and saving the time
taken in tamping.
=97.= Blasts are fired by electric fuses, Bickford fuse,
firing-tubes, needles, etc.
The fuses have been already described.
The _firing-tube_ is a very small iron pipe, which is inserted in the
powder charge and the tamping rammed around it.
After the tamping is finished the tube may be filled with fine powder
poured in it if the hole is vertical or inclined downward, or straws
filled with powder may be inserted if it inclines upward or is
horizontal. A “squib” of wet powder is also sometimes placed in the
tube and ignited, when it passes down the tube like a rocket and fires
the charge.
The _needle_ is a smooth copper wire, longer than the depth of the
hole. It has a ring handle, by which it may be turned around and
withdrawn. It is inserted in the charge, the tamping is well rammed
around it, and it is withdrawn, leaving a pipe in the tamping, through
which fire may be communicated, as described for the firing-tube.
=98. Tamping.=--The best and safest tamping is perfectly dry
silicious sand, poured in the hole so as to fill it completely, but not
rammed. It cannot be used in holes which incline upward nor when the
needle is used.
In such cases moist clay, brick-dust, etc., are used. The first layers
are pressed in upon the charge, and the subsequent ones thoroughly
rammed down with a copper tamping-bar. A hammer is used with the bar,
when necessary, in deep holes and hard rock.
_With high explosives no tamping should be used except dry sand or
water. Holes which incline upwards should receive an extra charge and
be untamped._
=99. Determining the Charge.=--The charge of gunpowder or high
explosive required for any particular hole in ordinary blasting can
be best estimated by an experienced blaster. If one is not to be
obtained, an approximate estimate for the first experiment may be
made from the formulas (counting the high explosives about four or
five times as strong as gunpowder for ordinary use), and the charges
for subsequent blasts may be estimated from the effects of those first
fired.
=100. Precautions.=--If a _tamped_ hole misses fire _it should
never be cleared out for recharging_. A new hole should be drilled
near, but not breaking into it.
Electric fuses or Bickford fuses (with blasting-caps for high
explosives) should always be used when they can be obtained.
DEMOLITIONS.
=101. Deliberate Demolitions=, such as the destruction of walls,
casemates, etc., in time of peace, or at a distance from the enemy in
time of war, should be so made as to economize powder and work. To
accomplish this, the mines and blasts should be located where they
will produce the best effects attainable, and the charges should be
proportioned to the work required from them.
The table previously given (p. 124) will serve as a guide for computing
the first charges used, and from the results of these the charges of
subsequent ones may be determined.
Judgment must be used in placing the charges, so that, when possible,
they will destroy the supports and allow the superstructure to break up
by falling.
The charges will usually be placed in chambers under or hollowed out in
the masonry. Sometimes they are more advantageously placed in a trench
outside and close to the foot of the walls. They should always be well
tamped: when in mine-chambers, by methods previously described; when
in trenches, or laid along the exterior of walls, by loading them with
earth, etc., until the line of least resistance passes through the wall
to be destroyed.
=102. Hasty Demolitions= are made when the time available for the
work is limited.
The structures usually destroyed are houses, walls, stockades, bridges,
tunnels, canal-locks, railroads, rolling-stock, etc., etc.
The time does not usually allow the charge to be placed in the most
advantageous position or to be properly tamped. For this reason the
high explosives are best suited for this kind of work, and large
charges are a necessity.
=103. Houses and Magazines= are best destroyed by placing several
charges with connecting trains inside and along the walls, laying
strong timbers upon them, with struts from the timbers to the floors
and roof above; barricading the doors and windows from within, and
firing the powder from a safe distance without.
=104. Walls.=--A wall not exceeding 3 or 4 feet in thickness may
be breached by charges of gunpowder placed at intervals along it.
Calling the thickness of the wall in feet _t_, the charge in pounds may
be 3_t_^3, placed at intervals of 2_t_.
For gun-cotton the Woolwich rule calls for charges in pounds of from
⅓_t_^2 to ½_t_^2 per running foot. Experiments made in New York with
dynamite indicate that the charges should be at least ½_t_^2 per
running foot, and for very good masonry should exceed this.
A charge of dynamite of ½_t_^2 per running foot will be given by a
cylindrical cartridge whose diameter in inches equals the thickness
of the wall in feet.[22] The effect of the charge will be very much
increased by throwing over it even a very light tamping of earth or
sand.
=105. Stockades.=--A strong stockade or palisade may be broken
down by charges of from 40 to 60 lbs. of gunpowder placed in contact
with it, and preferably covered with sand-bags. 10 or 15 lbs. of high
explosive should produce about the same effect.
=106. Bridges.=--Arched bridges are best attacked in the piers if
high and thin, or at the haunches and crown of the arch. Two or more
charges in the length of the pier, or width of the roadway, will be
more effective than the same amount in a single charge at the middle.
The charges should be placed in chambers cut in the piers or down
through the roadway to the back of the arch.
The abutments of single-span arches are generally very strong, and
the haunches well covered with earth and masonry. In hurried work,
therefore, the crown will generally be selected, a trench dug down
to it across the roadway, the charge placed in the trench, tamped if
possible, and fired.[23]
High explosives, from their shattering effect, are perhaps most
advantageously used by suspending them beneath and in contact with
the arch at the crown and haunches. The plank or timber upon which
they are placed should be as heavy as possible, in order to act as a
partial tamping, and should be drawn up so that the explosive will be
in actual contact with the soffit of the arch.
Under these circumstances they should produce as great an effect as
four or five times their weight of gunpowder.
Iron and wooden truss-bridges should be thrown down by breaking the
main braces near the piers, or the chords near the centre, by charges
placed in a joint if possible. High explosives are particularly
valuable for this purpose.
In wooden bridges they may be placed in auger-holes bored for them,
and in iron bridges inside the hollow members, between eye-bars, or in
other similar places.
=107. Tunnels, Canal-locks=, and similar constructions must be
attacked with large charges, so placed as to temporarily or permanently
disable the work, as may be considered necessary. The location of
each charge should be determined and its amount computed from these
considerations before the destruction is attempted.
A temporary obstruction is frequently all that is necessary or
desirable for these works, and the damage done to them should be
carefully regulated with a view to their subsequent repair and use.
=108. Railroads.=--Railroads are temporarily disabled by tearing
up the track, making hot fires of piles of ties, placing the rails upon
them so that they will heat and bend by their own weight; or, better
still, twisting the rails while hot by suitably-shaped steel hooks and
wooden levers of the kind devised by General Haupt (Pl. XII, Fig. 33).
Rails so twisted cannot be again used until re-rolled.
=109. Rolling-stock.=--Railroad cars may be disabled by breaking
one or more wheels with sledges, or may be destroyed by burning.
Locomotives may be disabled temporarily by carrying away the smaller
parts of the mechanism, or permanently by breaking the engine-cylinders
with sledges; bursting the boilers or burning out their fire-boxes by
drawing out nearly all their water, fastening down the safety-valves,
and building a hot fire in the furnaces; or by making a hot fire under
them so as to heat and thus bend or warp the reciprocating parts of the
machinery.
=110.= In all hasty demolitions with explosives the charges should
be well in excess of those computed by the ordinary rules: first,
because the explosives will not be so placed as to act to the greatest
advantage; and, second, because the demolition should be _immediate_
and _complete_.
INDEX.
A
PAGE
Additional operations--intrenched camps, 91
Advance from first parallel, 84
Advanced positions, 104
Advantage lies with attack, 176
Ammunition, 44, 57, 101
Angle template, 137, 148
Approaches, 16
Approaches, execution of, 20-3
Approaches, tracing, 18
Approaches, over-ground, 31
Ascending galleries, 148
Armament, 100
Army of observation, 69
Artillery, first position, 75, 104
Artillery, first position opening fire, 67
Artillery, second position, 81
Artillery, second position opening fire, 83
Artillery-fire, opening, by defence, 104
Assault, 4
Assault, defence against, 7
Assault, dispositions for, 5
Assault of breach, 89
Attaching a miner, 177
Attack by mines, 169-171
Attack by sap, 91
Attack, close, 107
Attack, journal of, 97
Attack, plan of, 78
Attack, point of, 73
Attack, successive steps of, 64
Auger, earth, 138
Auxiliary frame, 144
B
Battery, alternative construction, 50
Battery behind crest of hill, 53
Battery, breaching, 83
Battery, construction of, 48
Battery, constructing centre passage of, 48
Battery, counter, 82
Battery, definitions, 42
Battery, electric, 163-6
Battery, enfilading, 82
Battery, exposed sunken, 46
Battery for field-guns, construction of, 43
Battery for siege-guns and howitzers, 44
Battery for siege-guns, ammunition required, 44
Battery, general requirements of siege, 42
Battery, location of, 9, 75
Battery, mortar, 55
Battery of rifled mortars and howitzers, 83
Battery on sloping ground, 53
Battery, sunken, in a parallel, 51
Battery, tracing the, 47
Belfort, siege of, 71-2, 86, 104
Besieging force, bringing up and posting, 67
Besieging force, strength and composition, 70-2
Blasts, 178
Blasting and demolitions, 178-84
Blindage-frames or blinds, 156
Blinded descents or galleries, 38, 156, 170
Blinded sap, 38
Blinded sap, traverse by, 35
Blinds or screens, 45
Blockade, 1
Bombardment, 8
Bombardment, defence against, 10
Bombardment, defence during, 105
Bomb-proofs and traverses, 25, 170
Branches, 170-72
Breach, capture and crowning of, 89
Breaching batteries, 83
Breaching by mines, 176-7
Breaching galleries, 177
Breaching the scarp and counter-scarp, 88
Breaking out a full sap from a parallel, 30
Breaking out a double sap from a parallel, 33
Bridge, demolition of, 182
Bridge, floating--passage of ditch, 40
Brigade or detachment of sappers, 28
Bringing up and posting the besieging force, 67
C
Camps, fortifying, 68
Camouflet, 120, 167, 171, 172
Canal locks, demolition of, 183
Capitulation, the, 109
Capture and crowning of breach, 89
Capture and crowning of covered way, 87
Cases, mining, 139-41
Chamber, definition, 119
Chamber, form and location, 160
Changing direction of double sap, 33
Changing direction of galleries, 148, 150, 154
Changing slope of galleries, 149, 155
Charge, definition, 119
Charge, excess to be used in demolitions, 184
Charge for over- or under-charged mines, 125
Charge for blasts, weight determined, 179
Charge for blasts, when tamped, 178-9
Charge for common mines, 122-4
Charge for mines, placing, 165
Charge for mines, preparing, 161
Choice of explosives, 132
Churn-drill, 178
Circular place of arms, 31
Conquered place, occupation of, 93
Common mine defined, 120
Common mine volumes and charges, 120-4
Construction of battery for field-guns, 43
Construction of battery, sunken, 48-50
Construction of central passage, 48
Construction of magazine, 60
Construction of simple trench, 20
Construction of trench by flying sap, 22
Counter-battery, 82
Cover for bomb and splinter proofs, 23-25
Cover for magazines, 58
Covered way, crowning of the, 35
Crater, definitions, 119
Crater, assumed form of, 121
Crater relation between volume and charge, 120-7
Crater radius, definition, 119
Crowning the covered way, 35
Crutch, 154
D
Dampness, precautions against, 63
Defence, the, 99-111
Defence against assault, 7, 105
Defence against bombardment, 10, 105
Defence against surprise, 4
Defence, ammunition for, 101
Defence, armament for, 100
Defence by mines, 171-2
Defence, council of, 98
Defence during bombardment and assault, 105
Defence during first period, 103
Defence during second period, 106
Defence during third period, 107
Defence, garrison for, 99
Defence, journal of, 110
Defence, opening artillery fire by, 104
Defence, preliminary considerations, 98
Defence, preparations for, 101
Defence, provisions and supplies, 101
Demi-parallels, 86
Demolitions, deliberate, 180
Demolitions, hasty, 181
Descending galleries, 147
Detachment or brigade of sappers, 28
Detonation, 162
Dispositions for an assault, 5
Distribution of fuzes in charge, 161
Distance of line of investment, 70
Ditch, passage of, 37
Double sap, 32
Double sap, breaking out, from a parallel, 33
Double sap, changing direction of, 33
Double sap, execution of, 32
Drainage, 16, 24, 55, 59
Drawings, working, 151
Drill-bars and drills, 178
Dynamite, etc., 132-5
Dynamite, freezing of, 165
Dynamite, tamping, 179
E
Earth auger, 138
Electric batteries, wires, and lights, 165-6
Elevated and sunken batteries, 44
Elevated magazine, 62
Embrasures, 53
Enfilading batteries, 82
Execution of double sap, 32
Execution of single sap, 28
Experimental mines, 125, 131, 133
Explosion, theory of, 120
Explosive, charge for blasts, 179
Explosive, charge for mines, 122-5
Explosive, choice of, 132-5
Explosive, expenditure of energy, 120
Explosive, freezing of, 165
Explosive, noxious gases from, 133, 158
Explosive, relative strength of, 131, 179
Explosive, tamping of, 178-9
Exposed sunken battery, 46
F
False frame, 146
Field kitchens and ovens, 114
Field-level, description, 136
Field-level, use, 146, 148, 149
Filtration of water, 117
Fire, musketry, 84
Fire, opening by attack, 76
Fire, opening by defence, 104
Fire, opening from second artillery position, 83
Firing blasts, 178
Firing and loading mines, 161-6
Firing-tubes and needles, 178-9
First artillery position, 75
First parallel, 78
First period of the siege, 65
Flying sap, 20
Flying sap, construction of, 22
Fort Wagner, 86
Form and volume of crater, 121
Fortifying camps, parks, etc., 68
Frames and sheeting compared with cases, 141
Frames and sheeting, use in shafts, 139-45
Frames and sheeting, use in galleries, 145-51
Freezing of high explosives, 165
Full sap, 28
Full sap, driving of, 28
Full sap, breaking out from a parallel, 30
Fuzes, 161, 164, 166
G
Galleries, blinded, 156
Galleries, change of direction of, 148, 150, 154
Galleries, change of slopes of, 149, 154
Galleries, definitions and dimensions, 119, 138
Galleries, direction in attack, 171
Galleries, distance apart, 170
Galleries, for breaching, 177
Galleries, inclined, 147-9, 155
Galleries, listening, 170
Galleries of departure, 150
Galleries, partly lined, 148
Galleries, rate of advance of, 157
Galleries, transverse, 170
Gallery linings, 139-41
Gallery with frames and sheeting, 145-51
Gallery with cases, 153-6
Garrison of place, 99
Gases generated in mines, 133, 158
General requirements of siege batteries, 42
Globe of compression defined, 120
Governor of the place, 98
Guns, field, batteries for, 43
Guns and howitzers, batteries for, 44
Guns, ammunition required, 44-57
Guns for armament, 100
Guns of first artillery position, 76
Guns, positions of, to be changed, 106
Gunpowder, amount per cubic yard, 123, 124, 178
H
Hasty demolitions, 181
High explosives compared with gunpowder, 131-5
High explosives, freezing of, 165
High explosives, use in blasting, 179-80
Houses and magazines, demolition of, 181
Howitzer batteries, 44
Howitzers for vertical fire, 83
Huts and shelters, 113
I
Inclined galleries, 47
Infantry trenches, 104
Intrenched camp, attack upon, 91
Investment, 9, 65
Investment, distance of line of, 70-72
J
Journal of the attack, 97
Journal of the defence, 110
Jumper, 178
K
Kitchens and ovens, 114
L
Landings, 150-1
Latrines, sinks, etc., 115
Line of investment, distance of, 70
Line of least resistance = L. L. R., 119
Listening galleries or listeners, 170-72
Loading and firing mines, 161
Location of batteries, 9, 75
Location of magazine, 58
Lodgement, 170
M
Magazines, 57
Magazines, construction of, 60
Magazines, cover for, 58
Magazines, drainage of, 59
Magazines, elevated, 62
Magazines, execution of the work upon, 61
Magazines, location of, 58
Magazines, mined, 61
Magazines, precautions against dampness, 63
Maps, 151
Masks for batteries, etc., 45
Masks, air-tight, for exploring mines, 160
Maxims, Vauban’s, 94
Mine defined, 119
Mine-chamber, 160
Mine, common, 120-5
Mine, overcharged and undercharged, 120, 125, 131, 171-72
Mines of attack, 169, 171
Mines of defence, 171-2
Mines, organization of, 169
Mine tactics, 172-6
Mined magazine, 61
Mining, military, object of, 119
Miner, attaching a, 177
Miner’s bellows, 137
Miner’s candlestick, 137
Miner’s lamp, 137
Miner’s pick and shovel, 136
Miner’s rule, 122
Miner’s truck or car, 137
Mortar batteries, 55, 83
Mortars, siege, 57, 107
Musketry fire, 84
O
Observatories, 54
Occupation of conquered place, 93
Opening fire, attack, 76
Opening fire, defence, 104
Opening fire from second artillery position, 83
Opening the first parallel, 80
Organization and duties of brigade of sappers, 28
Organization and tactics of mines, 169-76
Ovens and kitchens, 114
Overcharged and undercharged mines, 120, 125, 171-2
Overground approaches, 31
P
Parallels, 15
Parallels, demi-, 86
Parallels, execution of, 20-3
Parallel, first, 78
Parallel, first, opening, 80
Parallel, first, advance from, 84
Parallel, second, 85
Parallel, third, etc., 86
Parallel, tracing a, 17
Parks, camps, etc., fortifying, 68
Parks and depots, 111
Partly-lined galleries, 148
Paris, siege of, 71-2
Passage, central, of battery, 48
Passage of the ditch, 37
Period, first, of siege, 65, 103
Period, second, of siege, 75, 106
Period, third, of siege, 86, 107
Pick and shovel, miner’s, 136
Pick, miner’s, distance heard, 170
Placing fuzes in charge, 164
Placing the charge, 165, 176
Plan of attack, 78
Plevna, siege of, 71, 72
Point of attack, 73
Posting besieging force, 67
Posting working parties, 18
Powder-boxes, 58
Powder for siege batteries, 44, 57
Precautions against dampness, 63
Precautions in blasting, 180
Preliminary considerations of defence, 98
Preparations for defence, 101
Preparing the charge, 161
Progress of the siege, 12
Proofs, bomb, 25
Proofs, splinter, 23, 48, 50
Provisions and supplies, 101
Push pick, 136
R
Radius of explosion, 119
Radius of rupture, 120, 128, 131
Railroads, demolition of, 183
Rate of advance of galleries, 157
Rate of advance of sap, 29
Regular approaches, 12
Requirements, general, of siege batteries, 42
Returns, 150-1
Rifled mortars and howitzers, batteries of, 83
Rolling-stock, demolition of, 184
S
Sand-bag fork, 13
Sap, attack by, 91
Sap, definition, 27
Sap, blinded, 35
Sap, breaking out from a parallel, 30
Sap, double, 32-3
Sap-fork, 13
Sap, flying, 20, 22
Sap, full, 28-30
Sap, shallow, 31
Sap-shield, 13, 23
Sap, traversed, 33-5
Sap, widening the, 30
Sapping, definitions, etc., 27
Sapping, former methods, 36
Scraper, 13
Screens, 45
Second artillery position, 81
Second artillery position, opening fire from, 83
Second parallel, 85
Shaft, definitions and dimensions, 119, 138
Shaft à la Boule, 156, 172
Shaft intervals, 142
Shaft linings, 139-141
Shaft mines, 172
Shaft, sinking, with cases, 152-4
Shaft, sinking, with frames and sheeting, 141-5
Shaft in a lodgement, 170
Shallow sap, 31
Shelters and huts, 113
Shield for covering ditch, 38-40
Shield for driving gallery, 147
Shovel and pick, miner’s, 136
Siege, definitions, etc., 12, 64
Siege batteries, 42-53
Siege, first period of, 65, 103
Siege, second period of, 75, 106
Siege, third period of, 86, 107
Siege, length of, 71
Siege of Belfort, Fort Wagner, Paris, Plevna,
and Strasburg, 71, 86, 104
Simple trench, 20
Sinking shaft with frames and sheeting, 141-5
Sinking shaft with cases, 152-4
Sinks and latrines, 115
Slope, defined, 119
Slope-block, 137, 148
Slope, change of, 149, 155
Slope, method of fixing, 147
Squibs, 178
Splinter-proofs, 23, 48, 56
Sterilizing water, 117
Stockades, demolition of, 182
Strasburg, siege of, 71, 86
Sunken battery, 45-53
Supplies and provisions, 101
Surprise, 2
Surprise, defence against, 4
Surrender of the place, 109
T
Tamping blasts, 178-9
Tamping mines, 166
Third period of siege, 86
Todleben’s rules, 173
Tools and appliances, 10, 136
Tracing approaches, 18
Tracing a battery, 47
Tracing lanterns, pickets, tapes, etc., 14
Tracing parallels, 17
Transverse galleries or transversals, 170
Traverse by blinded sap, 35
Traverse, cube, 34
Traverses, length of, 34
Traversed sap, 33
Trenches, 15
Trench cavalier, 36
Trenches, guard of the, 15
Trench, infantry, 104
Trench, simple, 20
Tunnels, demolition of, 183
U
Underground warfare, 169
V
Vauban’s maxims, 94
Ventilation of mines, 158-60
Vertical fire, batteries for, 83
Volume and form of craters, 121
Volume and weight of charge, 161, 181
W
Wagner, Fort, siege of, 86
Walls, demolition of, 181
Water-supply, 116
Weight and volume of charge, 161, 181
Wet ditch, passage of, 38-40
Working drawings, 151
[Illustration:
_Plate I._
_Bradley & Poates, Engr’s, N. Y._]
[Illustration:
_Plate II._
_Bradley & Poates, Engr’s, N. Y._]
[Illustration:
_Plate III._
_Bradley & Poates, Engr’s, N. Y._]
[Illustration:
_Plate IV._
_Bradley & Poates, Engr’s, N. Y._]
[Illustration:
_Plate V._
_Bradley & Poates, Engr’s, N. Y._]
[Illustration:
_Plate VI._
_Bradley & Poates, Engr’s, N. Y._]
[Illustration:
_Plate VII._
_Bradley & Poates, Engr’s, N. Y._]
[Illustration:
_Plate VIII._
_Bradley & Poates, Engr’s, N. Y._]
[Illustration:
_Plate IX._
_Bradley & Poates, Engr’s, N. Y._]
[Illustration:
_Plate X._
_Bradley & Poates, Engr’s, N. Y._]
[Illustration:
_MILITARY MINING Plate XI._
_Bradley & Poates, Engr’s, N. Y._]
[Illustration:
_MILITARY MINING Plate XII._
_Bradley & Poates, Engr’s, N. Y._]
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FOOTNOTES:
[1] In the siege of Strasburg, 1870, a bridge of beer casks was built
across the ditch of Lunette No. 52, between nightfall and 10 P. M.,
September 21st. The ditch was about 66 feet wide and 9 to 10 feet deep.
This bridge gave access to the lunette. It was subsequently sunk by the
fire of the work and was replaced by a causeway.--Franco-German War,
Official Account, Part 2, vol. 1., pp. 88, 89.
[2] One of a group of trees may frequently serve for this purpose.
[3] The charge for the 5" siege gun is 15 lbs. of powder; 200 rounds =
3,000 lbs.; 2 guns, 6,000 lbs.
[4] No special box has been adopted in our service. The English box is
1' 9" × 1' 5½" × 1' 5" outside, metal lined, and holds almost 100 lbs.
of made-up cartridges.
[5] The crater radius of a mine with L. L. R. of 6' to 12' and a charge
of 6,000 lbs. of powder would be about 44 feet (Art. 7, Military
Mining). The radius of the mound of earth thrown out would probably be
three times this.
[6] Quoted from Mahan’s Siege Operations.
[7] A shell from a 9" .45 rifled mortar has in experimental firing
produced in moderately hard ground a crater 8 feet deep and 19½ feet in
diameter.
[8] From the unpublished records of three experimental mines fired at
Willet’s Point in 1877-83 it would seem that the quantities given in
this table are greater than those required if good American powder is
used. These mines, in a soil of modified drift,
with a L. L. R. of 12 ft. required 1.02 lbs. per cu. yd. = 1 lb. ⅓ oz.; and
with a L. L. R. of 17 ft. required 1.15 lbs. per cu. yd. = 1 lb. 2½ oz.
[9] Six-lined craters (_r_ = 3_l_) are generally considered as the
practical limit of overcharged mines, although at Chatham mines have
been fired giving _r_ = (3-3/4)_l_. The published data concerning them
indicate that they required charges larger than the formulas above
given call for.
[10] Describe the semicircle _BMNF_. Then
_OD_ : _ON_ :: _CH_ : _CM_;
_l_ : _ON_ :: _v_ : _h_.
_ON_^2 = (_h_^2 _l_^2) / _v_^2. (1)
_BO_ : _ON_ :: _ON_ : _OF_;
_h_ + _r_ : _ON_ :: _ON_ : _h_ - _r_.
_ON_^2 = _h_^2 - _r_^2 (2)
_CF_ : _CH_ :: _CD_ : _CK_;
_h_ : _v_ :: √(_r_^2 + _l_^2) : _l_.
(_h_^2)(_l_^2)/_v_^2 = _r_^2 + _l_^2 (3)
∴ Eqs. (1), (2), and (3), _r_^2 + _l_^2 = _h_^2 - _r_^2.
_h_^2 = _l_^2 +2_r_^2 (4)
_h_ = √(1 + 2(_r_/_l_)^2).
* * * * *
Eqs. (3) and (4), (_l_^2 + 2_r_^2)_l_^2 = _v_^2(_r_^2 + _l_^2).
_v_^2 = (_l_^2 +2_r_^2)/(1+_r_^2/_l_^2) = _l_^2(1+2(_r_^2/_l_^2))/(1+_r_^2/_l_^2);
_v_ = _l_(√((1+2(_r_/_l_)^2)/(1+(_r_/_l_)^2))).
[11] General Abbot’s experiments in submarine mining fix the relative
values of cannon powder and dynamite No. 1 in water, measured by the
pressure exerted by them (not by the craters formed), as 1 : 2.45. The
characters of the media and the explosives would naturally lead to the
inference that the superiority of dynamite over powder would be greater
in water than in earth.--J. M.
[12] The 82 lb. dynamite-mine at Willet’s Point produced almost exactly
the same effect upon the gallery of access as the 200-lb. cannon-powder
mine, while its external crater was considerably less in diameter.
Its crater was surrounded, however, by concentric cracks spaced at
intervals of 3 or 4 feet to a distance of about 40 feet from the centre
of the crater. No such effect was produced by the powder-mine.
On the other hand, the actual radii of rupture produced by five
experimental mines fired at Olmutz in 1871-2 agree very closely with
the values which result from applying Lebrun’s formulas to craters
of the same size and shape produced by gunpowder, and indicate that
charges of dynamite and gunpowder which produce identical craters
will also have identical radii of rupture. The somewhat contradictory
results given by the Willet’s Point and Olmutz mines show the necessity
for further experiments.
[13] To pass a 5" siege-gun, mounted upon a high or “overbank” carriage
(model 1887), requires a gallery 7' × 7' in clear.
[14] Four of these may be unskilled laborers.
[15] No. required at commencement of gallery. Beyond 4 feet add one
man, and one additional for every 20 feet of gallery.
[16] Instead of a truck a canvas bag may be used. A large hoe or drag
may be used to draw back the earth from the face of the gallery.
[17] One mason’s level.
[18] These numbers are for small shafts of about 2' by 4'; large
shafts require a larger force. They advance at about the same rate as
galleries of equal cross-section.
[19] In the blasting at Hell Gate, 1870-76, several cases occurred,
both with nitro-glycerine and compressed gun-cotton, in which a part
of the charge exploded, breaking the blast-hole nearly to the bottom,
and leaving the remainder of the charge unexploded in the bottom of the
hole, from which it was subsequently recovered. Similar results were
obtained in experiments, conducted by Capt. (now Major) Heuer, 1875-6,
with long tubes filled with nitro-glycerine. See also Encyc. Brit.,
vol. xvi, “Mining,” for similar information.
[20] In compact soil the sound of a pick can be heard up to about 40
feet, and at about 20 feet when the miners are working as quietly as
possible.
[21] E.g., the sieges of Candia (1667-9), Schweidnitz (1762),
Silistria and Brailow (1828-9), Sebastopol (1854-5), Vicksburg (1863),
Petersburg (1864), etc., etc., and the experimental mining operations
at Graudenz in 1862. See Woolwich and Chatham Text-books, Mahan’s Field
Fortifications, Guerre de Siège Blanchecotte et Chauvot Fontainebleau,
etc., etc.
[22] A dynamite cartridge 1" in diameter weighs ½ lb. per running foot;
2" in diameter, 2 lbs. per ft.; etc.
[23] Capt. Schaw’s (R. E.) rule for an untamped charge of gunpowder
placed as above described is _C_ lbs. = ⅔ L. L. R.^2 × _B_, in which
_C_ = charge in pounds, _B_ = breadth of bridge in feet, and L. L. R. =
line of least resistance in feet, measured through the arch.
[Transcriber’s Note:
Obvious printer errors corrected silently.
Inconsistent spelling and hyphenation are as in the original.]
End of Project Gutenberg's Attack of Fortified Places., by James Mercur