SIEGE OR ATTACK BY REGULAR APPROACHES.
PRELIMINARY CONSIDERATIONS, DEFINITIONS, ETC.
=9.= By a regular siege is meant a systematic and more or less
deliberate attack upon a fortified place, in which the besieger aims
to invest the place and capture its fortifications in succession by
regular approaches, beginning with the most advanced and ending only
with the reduction of the innermost keep and the surrender of the
garrison.
The successive steps of a siege are usually the following:
The investment.
The artillery attack.
The construction of parallels and approaches.
Breaching by artillery or mines.
The final assault.
The introduction of modern breech-loading rifled guns, howitzers and
mortars, rapid-fire and machine guns, and magazine small arms has
brought with it the need of a higher grade of mechanical skill and
improved machinery for making the ordinary repairs. This imposes upon
both attack and defence the necessity for providing machine shops and
tools fitted for work of this kind, with the steam power required
to drive them. In connection with these, steam sawmills and other
simple wood-working machines should be provided, as well as all other
available labor-saving appliances which can be used to lighten the
labor of the troops.
Portable tools, such as picks, shovels, crowbars, rammers, axes,
hatchets, bill-hooks, gabion-knives, hammers, saws, carpenters',
joiners' and blacksmiths' tools, etc., etc., must be provided.
=10.= The principal =special tools and appliances= used are
the following, viz.: sap-forks, sand-bag forks, scrapers, sap-shields,
measuring-rods of various lengths, pocket compasses with attachments
for fastening them to measuring-rods, tracing-lanterns, dark and
ordinary lanterns, tracing tape or cord, tracing pickets or stakes,
fascines, gabions, hurdles, sand-bags, blindage and gallery frames and
sheeting, etc., etc.
The _sap-fork_ and _sand-bag fork_ (Pl. I, Figs. 1 and 2), about 4½ and
4 feet long, respectively, have steel heads with three and four prongs,
as shown in the figures, those of the sap-fork being sharp and those of
the sand-bag fork blunt.
They are used for handling and placing gabions, fascines, and sand-bags
in position when, without their use, the sappers' arms would be exposed
to fire.
The _scraper_ (Pl. I, Fig. 3) is a large hoe, of about the dimensions
given in the figure, used for levelling off the surface of parapets,
etc.
The _sap-shield_, introduced by the English (Pl. I, Figs. 4 and 6), is
a flat plate of mild steel 3 feet 6 inches by 1 foot 9 inches × ¼ inch,
with two handles on its back as shown. Total weight, about 80 lbs.
It may be used as shown in the figure, and sometimes by small parties
as a body-shield in such operations as blowing in gates, etc., etc.
_Measuring-rods_ of rectangular cross-section, straight and divided
into feet and inches, are needed for special purposes; but the ordinary
rods are cut from round brush wood and to the length required.
_Tracing-tape_ is usually a white tape, about 1½ inches wide, in
lengths of 150 feet, marked at equal intervals, usually 5 feet, by
short pieces of tape sewed to it. A loop of strong cord is fastened to
each end. For convenience in use it is ordinarily rolled into a ball.
_Tracing-pickets_ are about 18 inches long and one inch in diameter.
To make them visible in a dim light the bark is removed from them.
_Ordinary pickets_ are usually 3½ or 4 feet long, 1½ to 1¾ inches in
diameter, sharpened to a triangular point.
The _tracing-lantern_ (Pl. I, Fig. 5) is a dark lantern with a
reflector arranged to throw a light vertically downward.
The other tools, materials, and appliances above mentioned, not of the
ordinary commercial patterns, are described in Field Fortifications and
Military Mining, _q.v._