ORDNANCE

the chief developments in ordnance that have occurred since 1911 are in the nature of increased range and shell power. to these must be added the new guns required to meet the special conditions of the world war: the anti-aircraft gun, the tank and anti-tank guns, the trench mortar and the long-range guns. i. the gun gun construction and design.—the period since 1911 shows a tendency towards the use of steels of a higher yield point and a consequent increase in the use of alloy steels. the im- mense demands for alloy steels during the war and the difficulty of obtaining sufficient supplies led to a reversion to the use of carbon steel for small and medium guns with a consequent shortening of the life of these guns. since the war, however, there has been a demand for increased range without increase of weight of the equipment. to meet this it is necessary to use steels of great strength such as nickel chrome molybdenum and chrome vanadium. the general design of guns has altered but little. great britain retains the wire wound gun for almost all types, with a slight modification in breech end construction. fig. 1 is typical of present day british practice. continental nations retain the all-steel system of construction. manufacture—the great expenditure of ammunition and consequent rapid wear of guns in modern warfare renders the question of rapid and easy repair of guns a matter of paramount importance. british wire wound guns from 4 in. calibre upwards are fitted with removable liners known asinner “a” tubes, a feature which increases the weight of the piece, but facilitates repairs. other european nations retain the all-steel designs on the lines of the french or krupp systems (see 11.217). these, on account orders of knigh thood—ordnance of the heavy shrinkages necessary, are difficult to reline. many expedients have been adopted to speed up manufacture and repair. the british 60 pdr. and similar guns were manufactured without inner ‘‘ a’’ tubes, being subsequently bored out and fitted with the latter. short liners were fitted extending from the rear of the chamber, and over the worn region of the bore. these were, however, unsatisfactory and were abandoned. the end frame i. n\ ea shrunk collar \\ a aay la maner a tube: ae = : . breech bush chamber ‘ssk thn uv oe yy mmmm fic. 1.—sectional view of breech end of b.l. 15-in. gun. french in some cases adopted the system of boring out worn- out guns to a larger calibre. a 145 mm. gun was bored out after its first life to 155 millimetres. cluto-freitage.—a new method of building a gun termed “ auto- frettage ”’ (self hooping) has been tried by various nations. in a single tube gun pressure applied to the bore produces a tension in the various layers of the wall. this tension is at a maximum on the inside and decreases continually towards the outside of the tube. the successive layers will be deformed, the greatest defor- mation taking place at the surface of the bore. if the elastic limit of the steel is exceeded the deformation will be permanent. the metal of the layers least deformed, z.c., those at a greater distance from the axis of the bore, acts elastically on the layers beneath, producing a graduated shrinkage on those layers. it is argued that if a pressure equal to, or less than, that which has caused the deformation is subsequently applied to the gun no further deformation will take place. in the auto-frettage system the wall is permanently deformed by the application of hydraulic pressure to the bore. the advantage claimed for this system is that it will be possible to make small and probably medium guns of single tubes, thereby effecting savings in time, skilled labour and material. it is possible that the process may be applied to the relining of existing types, and to the manu- facture of large guns, using two or three tubes. the limiting factor appears to be the size of sound forging that can be pro- duced. trench mortars ——the trench mortar was a weapon originally designed for the destruction of wire, and short range bombard- ment in the siege of fortresses. prior to 1914 these weapons had been developed only by germany which used them with con- siderable success when trench warfare commenced on the aisne in sept. ror. the ordnance plants of the allies being fully occupied in the manufacture of guns, it was necessary to turn to the ordinary ordnance engineering firms for the supply of mortars. this necessitated a simple design capable of speedy manufacture with existing machines. three types have been employed:— i. the stick bomb type firing a large spherical bomb with cylin- drical stalk from a smooth bore gun of small calibre. this type was used by the british and german armies, but was discarded on account of its inaccuracy. 2. smooth bore mortars either muzzle or breech loading. the stokes mortar is of the former type, and the french 165 mm., in which the bomb is loaded from the muzzle while the propellant charge is loaded from the breech in a small case, is of the latter. 3. rifled muzzle loading mortars. ‘these were much used by the germans but require the use of special plants in their manufacture. the conditions of the war tended to crystallise the trench mortars into two main types: (a) a heavy mortar for bombard- ment purposes and (5) a light mortar to accompany attacking infantry for dealing with machine-guns and providing smoke screens. the former has been practically discarded under the conditions of mobile warfare contemplated by european nations; the value of the latter is a matter of controversy, but it is re- tained in some armies. long-range guns—in 1918 germany produced a gun of 21 cm. calibre which shelled paris at a range of 45 miles. similar guns of great range were constructed by various nations. these guns must be of great length which results in excessive wear and stripping of the copper driving band. shell for the german guns were provided with steel ribs to take the rotational thrust in addition to a gas check driving band. the effect of these guns was almost entirely moral. owing to their great cost and short life it is unlikely that they will be extensively employed in future wars, breech mechanism—with the introduction of the breech loading 6 in. 26 cwt. howitzer in 1916, a new type of mechanism known as the asbury type (sce fig. 2) was introduced. it was retaining catch breech mechanism lever holler iaeet plunger catch, breech rotating cam pn - bearing washer te percussion ph. stide box 'v" breech screw retaining fin for vent axial nut & safety shutter fic. 2.—general arrangement of breech mechanism of b.l. 6-in. 26 cwt. howitzer. subsequently adopted for the majority of medium and heavy guns in the british army. the breech screw is of the welin type with arm carrier. the rotation of the breech screw is effected by a vertical lever with crank connection to the breech screw. it is claimed for this mechanism that the lever is more conveniently situated for operating the breech than 1n the normal type with horizontal lever. the obturator is positively un- seated by a special cam on the breech face, and the breech 1127 screw is positively locked when the breech is open. semi- automatic mechanisms were introduced owing to the advent of aeroplanes and coastal motor-boats which demand guns that can fire extremely rapid bursts to counter them. the speed of loading these guns is increased by automatic ejection of the fired case and automatic closing of the brecch. these mechanisms are usually of the sliding block type; as the gun returns to the firing position a rod on the mounting fouls a pawl on the crank shaft of the mechanism, causing the latter to rotate and the breech to open; at the same time a spring is compressed. the spent case is ejected by the extractors which engage with the block and hold it open. on the loading of the next round the rim of the cartridge clears the extractors from the block which is then closed by the spring (see fig. 3). obturators—prior to 1914 the german army relied solely on the quick firing (q.f.) system in which the charge is contained in a brass cartridge case which effects the obturation. the british and french armies used the quick firing system for light guns breech block firing hole bush gas escape channel striker cover striker trigger sear firing spindle fntercocking lever locking lever cover plate catch plate plunger etc. crank shaft buffer block extractor plunger se ne fic. 3.—section of breech end of q.f. 3-in. 20 cwt. mark i. gun. and the “ b.l.” or de bange system for medium and heavy guns. the large expenditure of ammunition in the world war rendered the supply of brass cartridge cases a matter of great difficulty, so that an increasing tendency towards the ‘ b.l.” system is noted. germany still retains the “ q.f.”’ system as the sole method of obturation. improvements have been effected by the british, french and american armies in the de bange obturator with the effect of giving it a longer life. the latest design in the british service consists of an asbestos (with rape oil) pad enclosed in a brass gauze casing. the pad is protected in front by a thin copper disc with a split steel ring about its periphery. a similar ring protects the edge of the pad in the rear and a solid ring forms a bearing for the pad on the vent axial. (e. a. w.) il. the carriage all artillery carriages must be designed primarily, to provide a support for the gun during firing, and to allow of three separate movements:— (a) right and left in the horizontal plane. ...traverse (6) up and down in the vertical plane..... elevation (c) axially back and forward.......... seua recoil 1128 all carriages, therefore, are built up on the same general lines, and consist of two main portions:— the basic structure provides the support, and should remain fixed during firing. the super-structure provides for the three firing movements, and is divided into:— 1. carriage body, which is pivoted on the basic structure and is capable of movement in the horizontal plane to a greater or less extent according to the type of carriage. it consists of two stccl side pieces joined by transoms. on the top of each side piece is a bearing to receive the trunnions, one on each side of the cradle. 2, cradle, which is pivoted by its trunnions in the carriage body, and can be elevated and depressed in the vertical plane. i[t is so constructed that the gun can slide backwards and forwards through it, if it be a ring-shaped cradle; or on it, if it be trough-shaped. _ 3. recoiling parts, which connect the gun to the cradle and govern its movements. the superstructure, having in all cases the same functions to perform, does not alter greatly, except in size and weight for dif- ferent carriages. he type of basic structure depends altogether on the purpose for which the equipment is designed. guns of the fixed defences, for instance, which are securely anchored to the ground, and may have to traverse in any direction, have their basic structure circular in shape. semi-mobile equipments, which are moved to a temporary position in separate loads, cannot be anchored as firmly as fixed guns and have the basic structure a rectangle with its long sides in the line of fire, so as to provide support in the line of greatest shock. in this case the carriage body is pivoted near the front of the basic structure, and traverse is reduced to about 25 degrees each way. the mobile gun, or howitzer, must be ready to come into action at short notice, and so its basic structure must form a travelling as well as a firing support. thus, the basic structure in this case consists of a pair of wheels, an axletree and a trail. the mobile carriage may be supported at three or four points. three point support—only the two wheels and the point of the trail, which is secured by a spade embedded in the earth, are in contact with the ground. to preserve lateral stability the force of the recoil must not be allowed to act far to either side of the centre of the trail; consequently only a small angle of traverse—4 degrees each way—is possible without lifting the spade and moving the whole carriage. a wide space must be left, in the centre of the trail, into which the gun may recoil when firing at high angles of elevation. mention must be made here of a special type of three point support carriage, in which traverse is given by moving the front of the trail along the axle. in this case the carriage body becomes unnecessary, and bearings for the cradle trunnions are formed on the sides of the trail. the force of recoil always acts straight down the centre of this trail, which gives great lateral stability. a disadvantage, however, is that the spade forms the centre of the circle in which the front of the trail must move, and it follows that when the gun is traversed to the right, the right wheel must move back and the left wheel forward, and vice versa. this makes traversing very hard work on any but the most favourable ground and necessitates a somewhat com- plicated traversing gear. examples of this type are the british q.f. 18 pr. mark iv and the french 75 mm. guns. four point support—the amount of traverse given by ordinary three point support carriages is quite insuflicient for dealing with rapidly moving targets such as tanks and armoured cars. the need for more traverse is met by using a split trail, the halves of which can be splayed out for firing, each half having a spade at its rear end. this greatly widens the support in rear, and allows of traverse up to 25 degrees each way, while maintain- ing stability. at high elevations the gun is free to recoil between the legs of the trail. for travelling the legs are pinned together and hooked to a limber in the usual way. anti-aircraft equipments —for defence against aircraft, the first requirements are all round traverse and extreme elevation. this necessitates a carriage approximating in design to the fixed mounting. the basic structure consists of a base ring bolted down to the travelling platform. the carriage body, built specially high to allow of great elevation, has a circular race on ordnance its underside to fit over a “ live roller ring’? which revolves on the base ring and so facilitates rapid traverse. the travelling platform can be lowered from its wheelsto the ground and anchored for firing. possible developments —the rapid advance of mechanical transport and the increased use of tracked in place of wheeled vehicles for cross country work give an indication of the lines on which mobile carriages of the future may develop. tractor drawn artillery is now common, and it is easy to imagine that the mobile gun of the near future will leave its wheels, and fire either from the tractor itself, or from a tracked vehicle towed by the tractor. in either case the basic structure will probably be a circular pedestal clamped to the floor of the vehicle and capable of all-round traverse. gears.—to provide the necessary movements of the parts of a carriage in relation to one another certain gears are used. they are traversing gears, elevating gears and sight actuating gears. traversing provides for themovement of the carriage body on the basic structure in the horizontal plane. in its simplest form this gear consists of a nut and screw, the nut being held on a pivot at the rear of the carriage body, and the screw carried in a pivoted bearing on the trail in such a way that it can revolve but can have no lateral movement. the screw being turned by a handwheel, forces the nut to one side or the other, thus travers- ing the carriage body about its pivot. for heavy equipments and those requiring wide traverse, a more complicated system is employed; and may include one or more driving shafts with spur, bevel and worm gearing. elevating gear.—this provides for the elevation and depression of the cradle in the bearings of the carriage body. it is effected by a toothed arc or arcs attached to the cradle, and actuated by spur pinions on a cross shaft carried in the bearings in the carriage body. on one end of the cross shaft a worm wheel is keyed. a handwheel on the carriage body, working through spur or bevel gearing, if necessary, turns a worm which rotates the worm wheel and with it the horizontal shaft and its pinions. the pinions, being in mesh with the elevating arcs, impart the necessary movement to the cradle. it should be noted that the elevating arcs can, in many cases, be detached from the cradle, and are provided with hollow bosses which fit loosely over the cradle trunnions, so that arcs and cradle may move independently of one another when required. sight actuating gears may include spur, worm or nut and screw gearing, and are employed to give the neccessary move- ments to the axis of the sight, relatively to the axis of the piece. at the same time the angle, or equivalent range, at which the sight has been set with regard to the axis of the piece is recorded. sighting.—a gun carriage must provide means of laying the line of sight on the target, and of laying the axis of the piece at such an angle (tangent elevation) relative to the line of sight that the trajectory will intersect it at the target range. the arrangements are complicated by the necessity of allowing for the lateral movement of a projectile due to its spin, known as “drift? and for any difference in level of the wheels duc to uneven ground. the reciprocating sights used with modern carriages allow for drift and for difference in level of wheels by tilting the sight at an angle to the vertical. this is done by cross levelling a bubble mounted on the bracket which carries the telescope. two main sighting systems are used with mobile carriages:— 1. rocking bar system. in this case, the axis of the sight is first moved relatively to the axis of the piece, through the angle of tangent elevation. this is done by the sight operating gear. next, the gun and sight are moved together, by the elevating and traversing gears, until the line of sight is on the target. one man performs these two separate operations, a process much tvo slow for the engagement of rapidly moving targets. 2. independent line of sight. were the laying is done by two men. one, by means of the elevating and traversing gears, keeps the line of sight continuously on the target. the other, using the range gear, which moves the gun independently of the sight, keeps the axis of the piece continuously set at the angle of tangent elevation. as these movements can be carried out simultaneously and independ- ently, much time is saved. ordnance iii. buffers and recuperators the kinetic energy acquired by the gun on firing is absorbed by the buffer, recuperator and friction, and in this way the velocity of recoil is diminished, and the gun finally brought to rest. the recuperator is designed to store up energy so that it may return the gun to the firing position and retain it there at the maximum elevation. the buffer must absorb energy not accounted for by the recuperator and friction. in mobile carriages, to preserve stability, the heavier portion of the recoil system recoils with the gun, and a long recoil is provided for the same reason: further, as the gun recoils, the stability moment decreases, so the resistance to recoil must be correspondingly decreased. hence the system of graduated resistance is employed with mobile carriages. while the gas is acting on the gun, recoil should be as free as possible to preserve the aim, and reduce the couple on the recoiling parts. the ) +5) & 5 +) ld re) ce 8 s = 2 & recuperator recuperator [—iiletion recoil recoit fic. 4.—resistance space diagrams. graduated recoil (left) and controlled recoil (right). maximum resistance to recoil comes into action at the end of the period of free recoil, and then diminishes. fig. 4 (left) is a typical resistance space diagram for graduated recoil. the length of recoil is determined from the condition that the maximum recoil energy with free recoil (calculated from the ballistics of the gun) must equal the work done by the total resistance to recoil, 7.e., the area of the diagram. the buffer re- sistance can be obtained from the diagram, for the recuperative and frictional resistances can be calculated reasonably accurate- ly. british mobile equipments have centre trunnions, so recoil must be shortened as elevation increases in order that the recoil- ing parts may not foul the ground. recoil is then said to be controlled. the resistance-space diagram for such.a system will be similar to that shown in fig. 4 (right). since recoil is shorter and the total area must be the same, the resistance due to the buffer is greater than in graduated recoil (fig. 4 left), this in- crease in resistance does not affect the question of stability, since the stability moment increases with the elevation. with fixed mountings the question of stability does not arise, so short recoil is generally employed. further, the total re- sistance to recoil is a minimum when retained constant, and the system of equalised resistance is therefore adopted. the buffer —this consists of a cylinder filled with liquid in which works a piston and rod: either the cylinder or rod recoils with the gun; between piston and cylinder is a flow space for the liquid which decreases during recoil. the resistance to the flow of liquid through this flow space retards and finally checks the motion, and the resistance can be varied by suitably varying the flow space. the withdrawal of the piston rod at full recoil leaves a partial vacuum in the cylinder which assists the initial stages of recuperation, but before the buffer can act as a control to recuperation, the liquid must be banked up on the face of the piston remote from the rod. at this instant the recoiling parts have their maximum recuperative velocity: further, the flow space is increasing, and the resistance is insufficient to absorb the surplus energy. a further controlling device is therefore fitted to ensure the gun coming quietly to rest in the firing position. t129 the flow space, calculated and afterwards corrected experimentally, is varied by the following methods:— (2) accircular piston and longitudinal grooves of constant width and varying depth cut in the cylinder walls. (6) rectangular ports in the piston sliding over valve keys, metal bars contoured to give the required flow space, fixed to the cylinder walls. (c) ahollow piston rod with circular piston sliding over a tapered control rod fixed to the cylinder. ports in the piston provide a passage for the liquid. (dq) a valve with ports cut in it is rotated on the piston rod by feathers upon it engaging spiral feather-ways in the cylinder walls. it rotates against a valve having similar ports which is fixed to the piston rod. systems (a) and (4) are suitable for short recoil. system (d) is particularly adaptable to controlled recoil and is used in modern mobile carriages. controlled recoil necessitates cut off gear to reduce the flow space automatically as the gun elevates. a link or cam gear placed between cradle and carriage body rotates the piston rod through bevel or spur gearing. cut off therefore occurs earlier in the recoil stroke. control to recuperation is necessary to prevent a metal to metal blow, as the flow space in the buffer increases with re- cuperation. the following devices are in use:— (a2) acontrol plunger with a flat on it displaces liquid from a con- trol chamber, the chamber having filled with liquid on recoil. the most modern equipments combine an additional adjustable exit for the liquid with this system to suit special conditions. thus recupera- tion takes place in three stages: (1) unresistedl except by friction; (2) resisted by the buffer and friction; (3) resisted by the buffer, plunger and friction. (b) two separate valves, one to control recoil, the other to con- trol recuperation, the former being idle when the latter is functioning and vice versa. the system is best applied to the rotating valve type of buffer and affords two-stage contro! to recuperation. (c) a valve on the tapered control rod allows the hollow piston rod to fill with liquid on recoil, on recuperation the valve closes and the rod displaces the liquid through shallowing grooves in the hollow piston rod. recuperation is thus controlled from the outset. the recuperator.—this consists of a set of springs either in a single or a double column, or of a chamber containing compressed air; in either case it must be under sufficient initial compression to retain the gun in the firing position at the maximum elevation. part of the recoil energy is stored in the recuperator by further compressing either the air or springs, and this energy returns the gun to firing position. spring recuperator—a single column consists of one or more spiral springs, separated by parting plates, placed end to end on a compressor rod secured to the gun. the system is mounted in a case fixed to a cradle, so that on recoil the springs are com- pressed by the compressor rod. the telescopic system consists of two banks of springs separated by a hollow tube, but con- nected to each other by a flange at each end of the tube. the outer bank bears against the casing in rear, the inner bank against the compressor rod in front. on recoil the action is telescopic, so that the compression per column is reduced. for this reason the system is more suitable for long recoil equipments than a single column. in any case the life of a spring is limited and it is liable to fatigue. air recuperator.—air, initially compressed, is in contact, either directly or through liquid, with a piston, which on recoil further compresses the air. recuperators are thus classed as pneumatic or hydro-pneumatic, the latter class being subdivided according as the liquid and air are in contact or separated. liquid is used on account of the difficulty of sealing air at a high pressure. with pneumatic recuperators the air is sealed by a liquid gland, the liquid pressure being intensified in order to effect the seal. with the hydro-pneumatic system, one cylinder contains liquid acting on the face of a packed piston connected by its rod to the cradle cap, and communicates through a retard valve, port and pipe to another cylinder containing liquid and compressed air, the cylinders recoiling with the gun. the retard valve permits a free flow of liquid during recoil, but closes to control the rate of recuperation; the outlet of the pipe is arranged to be always below the liquid level, to prevent the air passing to the liquid cylinder. 1130 this system is liable to aeration, and in a more modern design, liquid and air are separated by a packed floating piston having a tail rod which intensifies the liquid pressure, reducing the tendency for air to escape. the tail rod also acts as an indicator for the quantity of liquid in the system, as it is visible from the front of the cradle cap through which it projects. the compression ratio should be low to reduce the final pressure and heating effect, and usually lies between 1-5 and 2. to give a low compression ratio the piston area should be small relative to that of the air cylinder, but, at the same time, it should be as large as possible to reduce the initial pressure for convenience in charging and sealing. from a knowledge of the compression ratio, piston area and length of recoil (which is the working length of the recuperator) the volume of the initially compressed air can be estimated. low initial pressure and low compression ratio entail bulky construction, particularly of the air cylinder; the design of the cradle limits the size of the system, and for this reason the initial pressure in a mobile equipment is generally higher than that in a fixed mounting. air recuperators, compared with springs, have the advantages that, firstly, an increase in power can easily be obtained without an increase in weight; secondly, run up can be controlled by the recuperator as well as by the buffer; and, thirdly, troubles due to fractured or fatigued springs are eliminated. on the other hand, air systems require skilled attention for their proper maintenance, and as they absorb a greater proportion of recoil energy than springs, a loss of pressure is much more likely to overload the buffer than a spring breakdown; correct charging is therefore essential. the air used in recuperators must be dry and free from dust to prevent rust and abrasion and to preserve the mirror surface ordnance and recent years have seen a steady increase in the size of the guns carried by warships of all types. | the 12-inch gun.—in 1911 the 12-in. gun, which for over 10 years had been the standard heavy gun for the navies of the world, had, in the british navy, reached the limit of its develop- ment in the 12-in. mark 11 50 calibre gun. this gun formed the main armament of the six battleships which followed the first ““ dreadnoughts ” and of the contemporary battle cruisers. in the first three battleships (‘ vanguard ” class} the guns were placed as in the “‘ dreadnought,”’ but in the “ colossus ”’ class the midship turrets were placed ‘‘ en echelon,” so that all ro guns could be fired on either broadside. this disposition of the main armament marks the transition stage to the centre line arrange- ment, which by 1915 had been adopted in the capital ships of all navies. in the secondary or anti-torpedo boat armaments, the 12-pdr. q.f. gun was replaced by a 4-in. q.f. or b.l. gun in all these ships. in contemporary ships in foreign navies the 12-in. gun still held its place as the main armament, but the desire to increase the heavy gun power was shown by both the united states and japan, who mounted 12 of these guns as against 10 in the british ships. the secondary armament in foreign navies was usually greater at this period than in the british ships. the japanese used a mixed arma- ment of 6-in. and 4-7-in. guns and the united states employed the 5-in. gun. by 1912 the demand for an increase in range combined with greater hitting power became insistent and a new gun—the 13-5 breech loading mark 5 was introduced into the british fleet. this gun, which weighs 68 tons and fires a 1,400 lb. projectile with a velocity of about 2,500 fs., shows a very marked advance in power over the most highly developed gun of 12-in. calibre. ten of these 13-5 guns formed the main armaments of the ‘ orion ” ss oe <p i= k fic. 5.—general arrangement of buffer and recuperator. necessary on the rods and cylinders; the use of air bottles charged with specially dried air instead of pumps minimises the risk of allowing moist air to enter a system, while the french favour the use of nitrogen instead of air. some expcrimental recupera- tors of stainless steel are being tried, but certain manufacturing difficulties remain to be overcome. a special liquid mixture is used in buffers and recuperators; it should be non-freezing in any climate, acid-free, non-inflammable and of slight viscosity which should be little affected by temperature change. only the specified liquid should be used, as it is for that liquid that the flow spaceis designed, but glycerine may be used in emergency. packings.—these may be distinguished as joint rings, soft packings and high pressure packings. joint rings, copper, leath- er or vulcanised fibre are used with plugs, stuffing boxes, etc., for standing joints. soft packings of asbestos, lead and hemp moulded to shape are used in stuffing boxes to seal under normal pressures, and to centre the rod. high pressure packings in the form of rubber or leather rings of “ u ” or “‘ l.” section are used to seal under high pressures. generally a combination of soft and high pressure packings is used. fig. 5 shows the general arrangement of a modern rotating valve type of buffer and hydro- pneumatic recuperator with floating piston as fitted to a mobile carriage. ce tc.) iv. naval ordnance war experience has proved that, at sea, victory will always rest with the side that can hit the hardest at the longest range, a. tail rod (leakage). 5 ‘ d. buffer cylinder. e. air reservoir. f. recuperator cylinder. g. recoil valve. #. rotating valve. 7. control plunger. & dust cover. z. air valve. wm. air filling plug. 6b. cut-off gear segments. c. floating piston. and “‘ king george v.” classes which were completed in 1912-3, and the battle cruisers of the ‘‘ lion ” class, built at the same time, mounted eight. in these battleships and battle cruisers, and in all subsequent capital ships built for the british fleet, the heavy guns are mounted on the centre line. thus the whole armament can be brought to bear, through a very large arc of fire, upon either broadside, and the maximum gun power is developed. in all these ships the 4-in. gun was retained as the secondary armament, but a change was made in the next class—the ‘“‘ iron duke ” completed in 1914. the main arma- ment of these ships remained the same but the 6-in. b.l. gun displaced the 4-in. in the secondary armament. the 15-inch gun—the year 1915 marked another great step forward in the gun power of the british fleet by the introduction of the 15-in. gun. this gun weighs 100 tons and fires a 1,920 lb. shell with a muzzle velocity of 2,504 foot seconds. the muzzle energy developed is thus twice that of the most powerful 12-in. gun, and as the rate of fire of the 12-in. and 15-in. guns is the same under battle conditions, upon this count alone the hitting power of a british batileship may be said to have been doubled be- tween 1912 and 1915. in addition, the heavier gun has a greater range—and what is most important of all—considerably greater accuracy at extreme ranges. the 1o battleships of the “ queen elizabeth ” and “ royal sovereign ”’ class each mount eight of these 15-in. guns in their main armament, supported by a powerful battery of 6-in. guns. the battle cruisers of the ‘‘ renown ” class have six 15-in. guns, ordnance, naval plate : . * = ' oe: pe mw, hel * see | oo. > i 4 gs ty boos poe lic. 1. 12-in. guns on h.mls. ‘ dreadnought ” (stern turret). fig. 2. 7-5-in. guns (bow) of h.m.s. “ effingham.” fic. 3. 4-7-in. guns of h.m.s. ‘* wallace” (‘‘ w "’. class destroyer). fic. 4. 15-in, guns of h.m.s. “ hood.” (photos. stephen cribb, southsea.) oregon with a reversion to the 4-in. gun, mounted in triple mountings, as a secondary armament. the ‘‘ hood,” which was the first capital ship completed whose design embodied the lessons learnt at the battle of jutland, carries eight 15-in. guns and a battery of 16 5-5-1in. b.l. guns. the armament of this ship is arranged in the same way as that of the “‘ queen elizabeth,” but the ship is much longer and faster. the 16-inch gun.—a further advance has been made in the size of the guns of the capital ships now being completed—the “‘ nelson ” and ‘‘ rodney.”’ these ships carry nine 16-in. guns of a new pattern in three triple turrets, all in the centre line forward in the ship, and the secondary armament consists of 12 6-in. guns in double turrets, three on each side in the after part of the ship. in other navies during the period 1911-25 a similar general in- crease in the size of the guns, both for the main and secondary armaments, has taken place. in both the united states and japanese navies, the 12-in. gun was replaced by the 14-in. in all ships built after 1914, and this gun remained the standard weapon in both navies until the ships projected in 1921, wherein a 16-in. gun has been adopted, the general arrangement of the armament being similar to that of the british ‘‘ queen elizabeth.” for the secondary arma- ment, the united states retained the 5-in. gun, until 1921, when the 6-in. gun was adopted. japan, on the other hand, after adhering to the 6-in. gun as the secondary weapon in her later ships, has now reverted to a gun of 5-5-in. calibre. the german navy was always one step behind other fleets in the size of the guns mounted in the main armament. the early german ‘* dreadnoughts ’’ were armed with the ii-in. gun, which had for many years been the heaviest weapon employed in the german fleet. after 1912, the 12-in. gun became the standard weapon for the capital ships and remained so until the battle of jutland in 1916. at this date, a few ships mounting i5-in. guns were approaching completion, but they were not finished in time to be actually em- ployed. the guns employed in the secondary armament of the german ships were similar to those in the british fleet—a 4-1-in. gun in the earlier ships or a 5-9-in. gun in the later ones. heavy guns and mountings.—~recent years have not brought about any very drastic changes in the main principles by which heavy gun turrets are worked. the most recent designs of twin turrets in the british navy show no very great difference in general arrangement from those in which the 12-in. guns were mounted in the earlier ‘* dreadnoughts. " the guns have increased from 12 in. to i§ in. in calibre, their weight and that of their ammunition has been more than doubled; consequently there are additional and more powerful machines, and many alterations in detail, but the genera! design has not been altered. the power used in the british navy for working the turrets is entirely hydraulic, supplied by hydraulic pumps which are situated outside the structure of the turret. the hydraulic system is heavy, but it is reliable and successfully withstood the severe test imposed upon it during the war, in the very large number of turrets afloat in the british fleet. any other system will have to be proved to be very reliable before it can be expected to supplant it. the japanese follow the british system, but in other navies elec- trical power has been used almost entirely for working the turret machinery. electrical machines have made great strides in efficiency and reliability in recent years, and the combination of electric motors and hydraulic transmission (ci the type of the williams-janney and hele-shaw machines) has rendered electric power peculiarly adapt- able to turret machinery. this system has been used in all recent united states designs and the increased use of electrical power for the auxiliary and possibly for the main engines of warships, may lead to the electro-hydraulic system being generally adopted in power- worked gun mountings, triple turrets.—triple turrets have appeared in most navies, but the british navy has been slow to adopt the innovation. the devel- opment is due to the desire to increase the gun power of the ships, without unduly increasing the size of the ships themselves. by the agreement made at washington the size of capita! ships is limited to 35,000 tons and of guns to 16-in. calibre. all nations therefore began to try to place the greatest gun power possible into ships of this size without sacrificing protection and speed and having due regard to the radius of action required of the units of each particular fleet. six guns mounted in two triple turrets occupy less length of the ship, which is one of the most important factors, than do the same number of guns in three twin turrets. weight of heavy armour is thus saved which can be used for other purposes. designs of quadruple turrets have been made, but it is not clear that economy of space results from their adoption, chiefly owing to difficulties in the ammunition storage and supply. there appears to be little doubt that the triple turret will be adopted by all navies in the near future. medium heavy guns and mountings——no modern capital ships now mount medium heavy guns in either their main or secondary armaments. guns from ii to 7-in. calibre are not powerful enough to be of any real use at jong range against armoured ships, and, since their ammunition is too heavy to be manhandled, they cannot be 1120 used for rapid fire, and would consequently ‘be out of place in the secondary armament. the relative weakness of the medium calibre gun was well illustrated at the battle of the falkland islands, when the german armoured cruisers, armed with 8-in. guns, speedily fell victims to the greater range and hitting power of the 12-in. guns of the british battle cruisers. in the mountings of 6-in. and smaller guns a general change has taken place as the result of war experience, from the old pedestal (p.) mounting to the central pivot (c.p.). this was necessitated by the demand for greater ranges and therefore increased elevation. in the p. mountings the elevation was limited to about 20°, as the bot- tom of the cradle carrying the gun then fouled the pedestal. in the c.p. mountings a circular plate is bolted to the deck, having a low pivot in the centre; on this plate is carried, on rollers, a revolving platform, the pivot being only used to prevent lateral motion. on the platform are built two transoms, on the top of which are the trunnion bearings, in which the gun and cradle swing in elevation between the transoms. the latest c.p. mountings for 6-in. and 4'7-in. guns admit of elevation of 30° or more. the c.p. principle has also been adopted for all anti-aircraft mountings in which eleva- tions up to 85° are necessary. anti-aircraft guns.——the rapid development of aircraft has called for a new type of armament in the form of the high angle gun. the commencement of the war found ail nations unprepared to meet the new form of attack. the menace had been realised, but none of the belligerent nations had advanced much beyond the ex- perimental stage in the development of an anti-aircraft armament, consequently a large number of improvised equipments were pro- duced, none of which were satisfactory. the problem of hitting an airship or aeroplane is a difficult one, since the target is moving in three planes at high speed. a vast amount of experience was ob- tained on shore during the war and high angle gunfire succeeded in making aircraft fly at a greater height and therefore the attainment of their objective became more difficult. at sea, much less experience was gained and the problem is a much more difficult one, since the platform upon which the gun is mounted is a moving and unstable one, thus adding greatly to the complications. all warships now carry two or more anti-aircraft guns. in the british fleet a 3-in. o.f. semi-automatic gun was used at first, but this has now been replaced by the 4 in. q.f. mark 5 gun on a spe- cially designed high angle mounting. the tendency is to increase the size of anti-aircraft guns. the first essential, however, for an efficient gun for this purpose is extreme rapidity of fire and a limit is imposed upon the size of the gun by the weight of the ammunition. a round of fixed ammunition for a 4.7-in. gun weighs about 80 ib, and this is as much as can be handled by one man with any degree of rapidity. it does not appear therefore that high angle guns will increase above this calibre unless a complicated power worked mount- ing is introduced, and this does not at present appear probable. (see gunnery: washington conference.) (s; fh w.) oregon (see 20.242), a state of the united states of america. the population in 1920 was 783,389 as against 672,765 in 1910, an increase of 16-4° : at the end of 1925 it was estimated at 1,007,- 725. the 1925 population of the 33 cities and towns with more than 2,500 inhabitants was 51° of the total population, as against 49-9 % and 45-6% in 1920 and 1910 respectively. forestry — in 1922 the virgin forest area was 21,344,000 ac., or about 34% of the total area. the timber stand in 1923 was 395,776,229 mill board feet. the total annual depletion of mer- chantable stand by fire and cutting during the years 1920-5 was about 1-2%. there were 14 national forests with an area of 24,086 sq. m. within the boundaries of the state. oregon ranked first in the nation as a timber-bearing state and second in lumber production. in 1923 it produced 12-61% of the na- tion’s soft-wood lumber; its cut was 3,800,000 mill board ft., valued at $110,000,000. the number of sawmills was 685; 45,000 men were employed and the lumber industry pay-roll was 65% of the entire industrial pay-roll of the state: 80% of the outgoing products were lumber and wood. agriculture —of the total land area 22:1% (13,542,318 ac.) was in 1920 included in the 50,206 farms; in 1925 14,170,043 acc., of which 4,984,375 ac. were improved, were in 55,909 farms. the gain in the total farm acreage during the decade 1910-20 was 15%, and from 1920-5, 4:3 %; the gain in the improved acreage during the decade was 14-9°%%, but from 1920-5 the shrinkage of tillable land in the farms was nearly 2°. the average value of farms and buildings was 12-4° less in 1925 than in 1920. the total value of farm property in ro10 was $528,213,782, and in 1920 was $818,559,751: 81° of the oregon farms were, in 1920, operated by the owners. ‘the crop values in 1920 were 192:7% higher than in 1910. the conspicuous increases in production in 1132 the decade ro10-20 were in forage, ensilage and fruits. the total ficld crops in 1920 were worth $131,884,639. live stock in 1925 consisted of 2,002,378 sheep, 483,813 beef cattle, 312,518 dairy cattle, 225,350 horses and 223,287 swine. in 1924, 16,250,000 lb. of wool were produced. mining —the mineral output includes gold, silver, copper, lead, platinum, quicksilver, portland cement, lime, clay products, monumental and building stone, coal, crushed rock, sand and gravel, diatomaceous earth, gypsum and mineral water. the total annual value is about $5,500,000, and in the years 1920-5 increased at the rate of about $250,000 a year. its most valuable mineral products are sand and gravel for building and highway construction and the common clay used in the manufacture of brick and drain tile. the expansion of mining activity has centred in the production of copper east of baker, and that in- crease adds to the production of the precious mctals associated with copper ores. industries.—oregon has distinct advantages for special lines of industry, including an abundance of raw materials, an equable and moist climate favourable to the production of textile fabrics, and readily available hydroelectric power. the relatively high transportation cost has been the main factor handicapping de- velopment. in 1914 oregon’s manufactured products were val- ued at $109,761,951 and the average number of wage-earners employed was 28,829: in 1925 the volume of output had in- creased to about $363,912,328, and employment was furnished to some 62,655 workers. the chief industries arranged in order of value of products were lumber and timber products, slaughtering and meat-packing, dairy products, woollen goods, printing and publishing and canning and preserving. trans portation.—in the years 1910-25 there were two distinct periods of transportation improvement. in the decade 1910-20 there were the opening of the main waterways, the extension of the railways (increasing the mileage by more than one-half), and a thorough commitment to the construction of a system of state highways with a consistent development. during the five years 1920-5 there was the maintenance of the channel depths of the waterways, the projecting and partial construction of the ex- tensions needed to complete the oregon railway network, and the continuation of highway construction. with the completion of the celilo canal in 1915, the columbia and its tributary, the snake, were made navigable to lewiston, idaho. through the construction of this canal above the city of the dalles a fall of 80 ft. in a stretch of 9 m. was overcome. with the transference to the federal govt. in 1915 of the canal and locks around the willamette falls at oregon city, the free use of the willamette was secured. the co-operation of the federal govt. and the port authorities of portland secured a deep-water channel in the willa- mette and columbia from portland to the sea. the railway construction during the decade provided :— (1) lines to the pacific coast, from portland to tillamook and from eugene to coos bay; (2) extensions into central orcgon with parallel lines up the deschutes river to bend and westward from vale in the snake river valley; (3) construction on the gap between natron and klamath falls as part of a double line for oregon- california traffic; (4) an electric line from portland to eugene and a steam line from corvallis to eugene. the railway mileage in the state in 1910 was 2,413-61; in 1920, 3,626:77; in 1925, 3,347 steam and 580 electric. in the period 1920-5 a 30-m. extension into central oregon by the oregon short line was completed, and construction activity on the natron-klamath cut-off has brought it almost to com- pletion. notwithstanding these additions to the railway mileage in oregon in the 15 years 1910-25, a complete lack of railway lines $till existed in the large southeastern section of the state, comprising about one-half its area. not only is the possible de- velopment of this section thus hindered, but the timber-covered area to the west has no direct transportation route to the great lumber market of the prairie states to the east. the development of a state highway system, begun in 1917, has been regularly carried forward: at the close of the year 1925 the total mileage was 4,463, of which 889 m. were paved and 2,188 m. had macad- orelli—orinoco am surfacing. a definite market road system for each county has been approved. . education.—in 1920 the total enrolment of grade-school and high-school pupils was 148,412; in 1925 1t was 187,982. funds for the maintenance of the schools increased 69% in the years 1920-5. afistory—during 1910-20 recourse was freely had to the ‘oregon system ”’ of direct legislation to enact constitutional amendments and statutory laws. through initiative petition, referendum petition and by vote of the legislature, 174 propos- als were submitted to the people; of these, 73 were approved. the people of oregon by this procedure established prohibition, woman suffrage and a rural credit system. citizenship qualifi- cation for the franchise, the right to veto single items in appro- priation bills, the abolition of the poll tax, classification of property for taxation and state-wide limitation of the rate of increase of taxation and indebtedness were also thus enacted. legislation also included the establishment of a minimum wage, workmen’s compensation and pensions for widows and a “ blue- sky law’ licensing sales of corporation securities. while three- fourths of the voters usually vote with the republican party, the representative leaders of the state during 1910-20 were two democrats, george e. chamberlain as u.s. senator and oswald west as governor. mr. chamberlain was promoted from the governorship to the senate. during the period 1920-5 the major- ity party was better able to maintain its unity, electing two governors in succession and sending a solid delegation of re- publicans to congress. in 1922, however, the democratic gov- ernor, walter m. pierce, was elected by a decided majority on issues of retrenchment and revenue reforms. in the decade 1910-20 the people of oregon began to demand more active progress in their state government. while there had been before 1910 4 half-hearted venture in railway regulation, later repudiated, and institutions of higher education had been receiving meagre support for some decades, the spirit of the con- stitution of 1857 was still dominant. later, however, the desire for an early realisation of an adequate highway system, and the assured prospect of regular revenues from automobile licences, led to the authorisation in 1917 of a state bond issue for the build- ing of a state highway system. the limit of indebtedness then fixed was 2°, of the assessed valuation. this limit was raised in 1920 to 4% for the state. the counties are authorised to borrow up to 6° of assessed valuation to secure funds for highway im- provement. the governors during 1911-25 were oswald west (dem.), ror1-5; james withycombe (rep.), rors-9; ben w. olcott (rep.), 1919-23; walter m. pierce (dem.), 1923- . (f. g. ¥.) orelli, hans konrad von (1846-1912), swiss theologian (see 20.251), died at basle nov. 8 1o12.