Part 103
The _supply division_ is provided with articles necessary to replace material lost or worn out, such as balk, chess, spare parts of carriages, a few complete carriages, etc.
The carriages of this division consist of ponton-, chess-, and tool-wagons, and of forges. Their number and proportion will be determined by the nature of the country in which the army is operating, and by the proximity of the main depot.
The ponton-wagon contains 17 long and 7 trestle balks. The chess-wagon, 60 chess. Tool-wagon No. 1 carries the same load as that attached to a ponton division. Tool-wagon No. 2 contains 80 rack-collars; of 6-, 8-, 10-, and 20-penny nails, 2 kegs each; of 4- and 6-inch spikes, 2 kegs each; of 1-, 2-, and 5-inch screws, 4 gross each; of 1- and 3-inch rope, 2 coils each.
The loads may be increased to the extent that circumstances will permit, by adding spare parts of carriages.
The forges are of the patterns A and B issued by the ordnance department.
_Advance-guard Equipage._--The trains of this equipage are composed of 4 ponton divisions, each of which consists of 8 ponton-, 2 chess-, and 2 trestle-wagons.
The load of the _ponton-wagon_ consists of 7 balks, 16 chess, 2 side frames, 1 cable, 1 anchor, and a ponton-chest containing 1 ponton cover, 14 transoms, 5 paddles, 2 scoops, 2 mallets, 20 lashings, 2 boat-hooks, 1 scoop-shovel, and 8 rack-sticks.
The _chess-wagon_ contains 50 chess and 2 spare ponton covers.
The trestle-wagon carries 14 balks, 1 trestle complete, 1 abutment sill, and 1 coil of 3-inch rope and 1 of 1-inch rope.
The forge is forge A of the ordnance department.
When necessary, this load may be reduced by transferring a part of the tools and coal to a forage-wagon.
The ponton-wagon carries all the material necessary for constructing a complete bay. The division may, therefore, be increased or diminished by one or more ponton-wagons without disorganizing it. When a forced march is to be made, and it is desirable to lighten the loads, the chess may be removed from the ponton-wagons, the rope from the trestle-wagons, and the load of the chess-wagons may be reduced to 40 chess. The number of the latter wagons in this case must be increased to five.
The tool-wagon is loaded with the necessary tools, materials, etc., suitable to the advance-guard equipage.
There are four methods of constructing a ponton-bridge: by successive pontons; by parts; by rafts; and by conversion.
_By Successive Pontons._--The location of the bridge having been selected, the ponton-wagons are brought as near the river-bank as practicable, with the rear of the carriage toward the stream. The pontons are unlashed and slid from the wagon-bed into the water; cables are attached to the anchors; one of the former is coiled in the bow of each ponton with its anchor on the top, the flukes projecting over the gunwale.
Those pontons which cast up-stream anchors are moored above the approach to the bridge, and the others below.
A trench about 1 foot in width and depth is excavated to receive the abutment sill; this should be laid horizontally, and exactly perpendicular to the axis of the bridge; it is secured by four pickets, two driven in front and two in rear, about 8 inches from each end. A ponton is brought up opposite to the abutment, and close to the shore. The ponton is then pushed off and adjusted in its place by means of shore-lines, which are made fast to mooring-posts.
As soon as the first set of balks is laid, a chess is placed on edge in the trench above mentioned, and in contact with the ends of the balks. Its upper edge should be 1¹⁄₂ inches above the balks. Earth is rammed behind it, crowding it firmly against the balks. The chess is then laid on.
The ponton which has cast the first up-stream anchor, having dropped down to the head of the bridge, is entered by the pontoniers. Five balks are then brought up and delivered to the lashers in the second ponton, which is pushed off; the shore ends of the balks are delivered to the lashers in the first ponton, who place them on the down-stream side, and in contact with those of the first set, their cleats against the outside of the interior gunwale. They lash the balks firmly together and to the lashing-hooks at both gunwales, and then step into the third ponton.
When a bay is covered with chess, the side-rails are laid. They are placed directly over the outside balks, to which they are lashed at three points,--at the middle and immediately over the axis of each ponton, at which point the two side-rails and balks of two bays lap and are all lashed together.
In constructing a ponton-bridge there are two points that require particular attention: the anchorage, and the lashing; the men who are intrusted with their execution should be selected from the most intelligent and experienced pontoniers in the command.
_The Anchorage._--The distance of the anchor from the bridge should be at least ten times the depth of the stream; with a less distance the bows of the ponton would sink too deeply in the water.
The direction of the cable when made fast to the bridge must coincide with that of the current,--_i.e._, a ponton in the bridge must have the same position which it would assume if riding freely at anchor. It will be remembered that the cable is not finally made fast to the ponton which casts its anchor, but to the one following it in the bridge; and due allowance must be made for this in selecting the place for casting anchor.
The number of anchors required will depend somewhat on the strength of the current. It is generally sufficient to cast an anchor up-stream for every alternate ponton, and half that number down-stream; but where the current is very rapid it may be necessary to anchor every up-stream boat, especially near the middle of the bridge. The number of anchors cannot be much diminished, however moderate the current, as the anchorage has a very marked effect in checking the horizontal oscillation to which bridges are subject when troops are marching over them.
_The Lashings._--With respect to the lashings, the corresponding balks of adjacent bays lap each other by 6 feet, and are lashed together and to the gunwales at two points about 5 feet apart. Thus a strong splice is formed, making five continuous beams running the entire length of the bridge. The stability of the bridge is further increased by the manner of placing and securing the side-rails.
_By Parts._--The abutment bay is formed as in the previous method. The parts are constructed at suitable points along the shore above the bridge, and for each is required the material for three bays. They are constructed as follows:
A ponton is moored bow and stern close to the shore, and five chess are temporarily laid from the bank to its interior gunwale, for the convenience of the pontoniers during the construction of the part.
The other two pontons are brought up in succession, and two bays are constructed in the ordinary manner, except that six chess are omitted from the roadway at both ends. Twenty-six chess and seven balks are loaded on the parts thus formed, which is then pushed off and conducted to the line of up-stream anchors, where it casts its anchor and drops down to its place in the bridge.
The first part is connected with the abutment bay by the pontoniers on shore, who construct one length of bridge flooring in the usual manner, to join the abutment ponton with the first ponton of the part.
The other parts are united as they come in position, by bays formed from the balks and chess with which they are loaded.
The down-stream anchors are cast by separate pontons provided for the purpose; and it may sometimes be necessary to cast the up-stream anchors in the same way, as the parts are not easily managed in a rapid current.
When the current is moderate, the parts may be constructed below as well as above the bridge.
_By Rafts._--The abutment bay is laid in the same manner as in the last method, and the rafts differ from the parts only in having the roadway completed,--that is, the six chess at each end are not omitted. The rafts are not loaded with extra balks and chess, but are provided with two false balks, 6 feet 9 inches by 5 feet 5 inches, and with four rack-collars and wedges.
The rafts cast their up-stream anchors, and drop down to their places in the bridge. The outer pontons of the adjacent rafts are in contact, and are lashed together bow and stern by their mooring-posts. False balks are laid over the side-rails of the two rafts at their junction; and two rack-collars embrace each false balk, and the side-rails and balks under them. These collars are placed on each side, and 2 feet from, the junction of the side-rails. The wedges are driven between the false balks and the tops of the collars.
_By Conversion._--The position of the bridge having been determined, and the width of the stream accurately measured, a suitable place at some distance above the position of the abutment is selected for the construction of the bridge. This place may be at a considerable distance from that which the bridge is to occupy; it is frequently on some tributary of the stream to be bridged, out of sight of the enemy’s shore.
The bridge is constructed parallel to the shore; side-rails are lashed on all except the extreme bays. The balks, chess, etc., for the abutment bay on the enemy’s side, are embarked on the next to the last bay of the bridge; a ponton is lashed to the last ponton in the bridge; this contains, in addition to the articles necessary for constructing the abutment, two strong pickets. The up-stream anchors are deposited in the bows of the boats on the wheeling flank, 10 or 15 yards of their cables coiled, the remainder stretched along the bridge. Two strong spring-lines are extended and lashed, the one over the bows, the other over the sterns of all the pontons; these lines should be considerably longer than the bridge, and the ends coiled on the platform. The bridge is then allowed to float down to within 15 yards of the first abutment.
The material for the first abutment and bay is brought down in a ponton. Two strong pickets are planted to receive the spring-lines and two to receive the shore-lines, which are coiled on the platform between the first and second pontons.
The wheeling flank is pushed off, and men are stationed in the bow and stern of each ponton with oars and boat-hooks to increase or retard the progress of their ponton, as may be necessary. A detachment is stationed at the first abutment to manœuvre the spring-lines; another to prevent the pivot flank from touching shore; a turn of the shore-line is also taken around the mooring-post of the ponton, and this line is eased off, as the case may require. The anchors are cast as the pontons in which they are carried come in their proper places, and their cables are shifted to the pontons to which they are to be attached. The progress of the bridge is checked when it arrives opposite the abutments, which should be constructed during the conversion of the bridge, if the force be strong enough.
The down-stream anchors are cast by the spare pontons, as in the bridge by successive pontons.
_Flying Bridge._--This term is applied to any floating support anchored to a fixed point (usually in the stream), and driven from shore to shore by the oblique action of the current on its sides.
Although these bridges do not afford a continuous communication, yet they possess some decided advantages, viz.:
They are readily established, even over the most rapid streams.
They require but little material for their construction.
They may be worked by very few men.
They permit the passage of troops of all arms, and of the heaviest carriages.
The entrance to and exit from them is easy.
They do not interrupt navigation; and they are not liable to be injured by floating bodies which, either by accident or design, are carried down-stream by the current.
The current should not be less than one yard per second.
_To Construct the Raft._--The raft is formed of six pontons. Two pontons are lashed stern to stern, and to these a third, breaking joints. A second set similar to the above are placed at a distance from the first of 26 feet from set to set. The two sets are connected by six balks over which four courses are lashed. Then fifteen balks in a manner suitable for receiving chess. The extreme chess are nailed down, and the outer courses secured by side-rails. The length of the cable should be at least one and a half times the width of the river. One, two, or three anchors are used, depending on the strength of the current. The cable is supported by pontons. The boat nearest the anchor is the largest; the distance between the boats should be such that the cable shall not touch the water between the first boat and the raft; each boat is fitted with a staging, composed of two short balks, and a supporting block, on which the cable rests and to which it is lashed. The cable is also connected with the bow of the boat by a line of such length that the boat is allowed to turn just enough to keep parallel with the raft. After the raft is attached to the cable it is passed from shore to shore once or twice, using a stern veering-line if necessary, until the anchors are firmly imbedded and the cable is stretched; the two abutments are then constructed; these do not differ from the first bay of the ordinary bridge.
The proper angle for the axis of the boat to make with the current is about 55°. This angle is gradually increased on nearing the shore, until the way of the raft is diminished sufficiently to prevent it from striking the abutment with a shock.
_Trail Bridges._--When the river is not more than 150 yards wide, a sheer-line may be used in place of the anchor and cable; the sheer-line must be taut enough to keep above water.
If the banks are not high enough, the sheer-line should be elevated at each shore by passing it over a frame formed by three poles, arranged like an artillery gin. Upon this line a pulley is fixed, so that it can run freely from shore to shore; through the eye of the pulley-block a line is passed, one end of which is attached to the bow of the first, and the other to the bow of the second, boat forming the raft. The raft is manœuvred in the same manner as the flying bridge; or one end of a line may be made fast to the running-block on the sheer-line, while the other passes through a snatch-block near the stern of the raft on the up-stream side; by hauling in or letting out this line the proper direction is given to the raft.
_Rope-ferries._--The rope-ferry is used when the velocity of the current is not sufficient to propel the raft. It consists of a raft or flat, provided with a standard near each end on the up-stream side. These standards are forked on top to receive the sheer-line, which is stretched across the stream in the same manner as for the trail bridge. The raft is propelled across the stream by men on its deck hauling on the sheer-line.
_Prairie Raft._--It frequently occurs in the Western country that expeditions, unaccompanied by regular ponton-trains, are compelled to cross streams so situated that it is impossible to obtain timber or other material suitable for the construction of rafts or bridges. Under these circumstances, a raft may be constructed of two canvas pontons, by means of which loaded wagons may readily be ferried over the stream. All the material required for such a raft is easily carried in one ponton-wagon. The construction is as follows: The wagon to be floated is backed into the stream until the rear wheels stand in about one foot of water. A canvas ponton is placed on each side of the wagon, parallel to and one foot from it. A balk is placed against the tail-board of the wagon, and resting upon the gunwales of the pontons. A second balk is similarly placed against the front-board of the wagon. On each side of the wagon a strong rope is made fast to the front balk, passed under the axle-trees round the rear balk, and thence back to the starting-point, where it is made fast. The raft and wagon are pushed into the stream, and, as soon as the latter is clear of the bottom, the balks are lashed to the gunwales of the pontons. A line is attached to the wagon-pole, and coiled in the bow of one of the pontons. This raft may be conveyed across the stream either by rowing, or in the manner of a trail bridge. On approaching the opposite shore, it should be turned with the wagon-pole toward the bank. As soon as the wagon grounds, the balks are removed and the wagon is drawn on shore by means of the rope attached to its pole. A single hinged canvas ponton, which is readily packed in an ordinary quartermaster wagon, will suffice for the crossing, if the wagons are unloaded and taken apart.
_Box Pontons._--In localities where plank and boards can be conveniently procured, pontons may be constructed very expeditiously, by placing ten partitions of 2-inch plank, each 5 feet long, and 2¹⁄₂ inches high, in parallel positions, on the top and sides of which boards are nailed: the box thus formed to be covered with pitched canvas, as described in the mode of constructing crib pontons.
_Wagon-body Pontons._--Ordinary wagon-bodies, covered with pitched canvas or india-rubber blankets, may be used either as boats or pontons. The small capacity of the wagon-body requires such pontons to be placed more closely to compensate for it.
=Ponton-train.= See PONTONS, BRIDGE EQUIPAGE.
=Pontus.= An ancient kingdom in the northeast of Asia Minor, which derived its name from its being on the _Pontus Euxinus_ (Black Sea), extending from the river Colchis in the east to the river Halys in the west. In early times, its various parts were designated after the tribes which inhabited them. The most important of those tribes are,--the Leucosyri, Tibareni, Chalybes, Mosynœci, Heptacometæ, Drilæ, Bechires, Byzeres, Colchi, Macrones, Mares, Taochi, and Phasiani. From the middle of the 7th century B.C., many of those tribes inhabiting the coast rose to great power and opulence, spreading Greek culture and civilization around them; while many of those of the interior were extremely savage and wild. According to tradition, it was conquered by Ninus, founder of the Assyrian empire; and it was certainly under the Persian dominion after the time of Cyrus the Great. In the reign of Artaxerxes II., Ariobarzanes conquered several of the Pontian tribes, and laid the foundation of an independent kingdom. Mithridates II. succeeded him 337 B.C., who by availing himself of the disputes of the successors of Alexander, considerably enlarged his dominions. Under Mithridates VI., from 120 to 63 B.C., the kingdom of Pontus rose to its highest dignity. In his war with the Romans his kingdom was dismembered by Pompey in 65 B.C., who annexed the western part of the nation, and gave the remainder to the native chiefs. In 63 A.D. Pontus was made a Roman province, and in the changes which transpired under Constantine the province was divided into two parts.
=Pontvalent.= A kind of light bridge, used in sieges, for surprising a post or outwork which has but a narrow moat; a flying bridge.
=Poor Knights of Windsor.= See KNIGHTS, MILITARY.
=Port Royal.= In Beaufort Co., S. C., noted as one of the earliest settlements made by the Spaniards within the present limits of the United States, and for important events during the war of the Rebellion.
=Portable Forge.= A light and compact blacksmith’s forge, with bellows, etc., that may be moved from place to place; used frequently in the quartermaster’s department.
=Portate.= In heraldry, borne not erect, but athwart an escutcheon; as, a portate cross.
=Portcullis.= Is an assemblage of several large pieces of wood, joined across one another like a harrow, and each pointed with iron at the bottom. They are sometimes suspended over the gateway of old fortified towns and castles, ready to be let down in the case of surprise, when the gates cannot be shut.
=Portcullis.= In heraldry, the portcullis is represented with rings at its uppermost angles, from which chains depend on either side. It was a badge of the Beaufort family, and borne in virtue of their Beaufort descent by their Tudor sovereigns. Portcullis is the title of one of the pursuviants belonging to the English College of Arms, whose office was instituted by Henry VII.
=Port-fire.= See LABORATORY STORES.
=Portfolio.= A portable case for keeping loose papers in. Hence, also, the office and functions of a minister of state or member of the cabinet; as, to receive the portfolio of war.
=Portglave.= An ancient name for a sword-bearer.
=Portland Isle.= An island off the coast of Dorset, England, which was fortified before 1142.
=Porto= (or =Puerto=) =Bello=. A seaport town of South America, on the north coast of the Isthmus of Darien.
=Porto Novo.= A seaport of British India, in the Presidency of Madras, at the mouth of the Vellaur. It suffered severely in the wars of the British government against Mysore, and fell into a state of decay. At Porto Novo, Hyder Ali, with an immensely superior army, was totally defeated by the British under Sir Eyre Coote in 1791.
=Porto Rico.= A Spanish possession, one of the group of West India Islands called the Great Antilles. Porto Rico was invaded in 1509 by Spaniards from Hayti, and the natives were soon exterminated by them. Towards the end of the 17th century the island was captured by the British, but was abandoned by them soon afterwards. In 1820 a revolution took place in Porto Rico, which was finally put down in 1823.