through six generations to O-Kuni-Nushi, a moon-god who with his son, Koto-Shiro-Nushi, are now popular as gods of wealth, under the names of Daikoku and Ebisu. The former is seated on rice bales, the latter holds a fish, these being the staple foods in Japan.

In accordance with the evolution of religion, the Kojiki now passes from the origin of its gods in myth to the origin of its rulers and priests in legend, and of course secures authority for the latter by derivation of them from the former. Thus the Kojiki relates how Amaterasu produced by magic a son, Ho-Mimi, whose begotten son, Ninigi, at her command, descended from Heaven with a retinue of nobles and priests, deposed O-Kuni-Nushi, and founded that Imperial Dynasty which still after two millennia rules in Japan, "in lineal succession unbroken for ages eternal." The Imperial Oath, prefaced to the Constitution of Japan, promulgated in 1890, appeals to the "Imperial Founder of our House," namely, Jimmu Tenno, greatgrandson of Ninigi, who was in turn supposititious "sovereign grandchild" of Amaterasu-O-Mi-Kami. The "Heaven" from which Ninigi, with his nobles and priests, really descended was Korea, as the Kojiki naively implies and as certain monuments show.

After his abdication and death, O-KuniNushi became (according to his Kyushu conqueror) as "Great Deity of Miwa," ruler of the "invisible," by which was meant the world of thought and secret action which escapes the notice of the earthly ruler. The tutelary gods of every province must report at O-KuniNushi's shrine in Izumo every October (hence called everywhere except in Izumo the "godless month") upon the condition of each individual's soul. O-Kuni-Nushi then punishes or rewards by means of the natural good and evil that befall men. Later he became a ruler of the dead. The mythical element in the Kojiki now decreases and legend passes into annals which close in the 5th century A.D.

The ancestor and hero worship of Shinto was absorbed by Buddhism, since the latter professed especial knowledge about the future life; though each district managed to retain an Ujigami, Clan god, to whom infants were presented for adoption and naming. Hero worship is maintained mostly in these Ryobu, "Two Faced," shrines. Such were TenjinSama, "Heaven Spirit Lord," originally the minister of state and scholar, Michizane of the 10th century A.D.; Hachiman San, an apotheosis of the Emperor Ojin of the 4th century A.D., as God of War; Ieyasu and Iyemitsu, 17th century shoguns of Japan, with gorgeous temples at Nikko; and Motoori, a patriotic scholar apotheosized during the last reign. Until the revolution in 1868 two living persons were regularly treated as divine; the Mikado still styled Tenshi Sama, "Heaven Son Lord," descendant of Amaterasu-O-Mi-Kami; and the highpriest of the Izumo O Yashiro, being the 76th gencration from O-Kuni-Nushi, and until 1868 styled Iki-gami, "Living-god."

The Yengishiki, "Ceremonial Law," compiled 927 A.D., from much older sources, is a worthy companion to the Kojiki. It contains 27 rituals, which consist, not of free petitions, but of statements of the grounds upon which the offerings, which are the essential thing, are made, namely the reception of some natural

good. The famous Obarsi, performed for the whole nation 30 June and 31 December, affords a single exception to this quest for natural good. The Kagura is a popular occasional ceremony, a peace offering of food, music and dancing made to any deity by the temple attendants — usually the daughters of the resident priest at the request and expense of any worshipper. The priests marry, their office is hereditary, but may at any time be abandoned, and distinctive dress is worn only when they are officiating. They make no claims to personal sanctity or authority.

The infrequent preaching of the priests always appeals to the examples of the gods, and for positive rules to the laws of that Tenshi Sama who rules by divine right. As for the rest of conduct, "Human beings, having been produced by the spirit of the two Creative Deities, are naturally endowed with knowledge of what they ought to do and what they ought to refrain from. It is unnecessary for them to trouble their heads with systems of morality."N. Matoori. The Kurozumi, a sect founded a century ago, and now having about a million adherents, practises mental healing by various rites, and by accord with two commandments: Thou shalt not be without a constantly believing heart. Thou shalt not yield to anger nor grief.

Bibliography.- Chamberlain, B. H., The Kojiki' (being Supplement to Vol. X in Transactions of the Asiatic Society of Japan, 1882); Satow, E., article in the Westminster Review (July 1878); 'Ancient Japanese Rituals' (in Transactions of the Asiatic Society of Japan (Vol. VII, Part 2); Shinto (ib., appendix to W. G., Shinto) (1905).

Revival of Pure Vol. III); Aston,

EDMUND BUCKLEY.

SHIP. A ship is a large boat, or vessel, intended for navigating the ocean. Technically a ship is a vessel carrying not fewer than three masts rigged with square sails. In the present day ships are of two kinds, sail and steam. For a history of the former see the article SAILING VESSELS, and for a historical sketch of steamships, see the article STEAM VESSELS. A detailed description of vessels used in naval warfare will be found under the title WARSHIPS.

A ship has three principal dimensions: length, beam and depth. Length is the straightline horizontal distance from bow to stern. It is officially measured on the upper side of the upper deck of vessels having less than three decks, and on the second deck above the keel on all other ships; the beginning point being the inside of the inner plank at the side of the stem and reaching to the inside of the planking at the midship stern timber; deducting the amount of rake of the stern timber in the thickness of the deck, and one-third of the fore-and-aft round into the beam. The "beam" is the horizontal distance amidships taken at right angles to the length. Officially it is measured from inside to inside of the planking on the under side of the measurement deck. The depth is the vertical distance from the under side of the beams of the deck of measurement to the keelson. That part of the depth of a ship below the water-level is called the draught; that part above the water-level is termed the freeboard. The draught and freeboard vary according to the weight of cargo

carried, the draught being more and the freeboard less when the weight is greater.

The principal requirements of a ship are buoyancy, stability, strength, capacity and speed. The buoyancy of a vessel depends upon its ability to displace a greater weight of water than the weight of the materials of which it is built. The weight of water (in tons) thus displaced is called the displacement of the ship; and as salt water is heavier bulk for bulk than fresh water, with the same load a ship will ride higher in salt water than in fresh. The centre of buoyancy is equivalent to the centre of gravity of the mass of water displaced by the ship. When the ship is at rest in placid water it is located at a point in the vertical line passing through the centre of gravity of the ship. It is the point at which the pressure of the water in which the ship floats is theoretically centred - as the force of buoyancy. This force, however, acts not at the centre of buoyancy, but vertically upward through that centre. As the ship rolls under the action of waves or of wind the centre of buoyancy shifts. In Fig. 1, the continuous lines show a sectional diagram

FIG. 1.

(amidships) of the vessel at rest in placid water: the dotted lines show the vessel heeled over by wind and wave. The centre of buoyancy has swung from B to B'; the centre of gravity moves to G'. XB' shows the position of the force of buoyancy, and G'Z the force moving to right the ship to an even keel. Stability is that quality of a ship by virtue of which it resists overturning. The nearer the centre of gravity of the ship can be brought down (in the loading) to the centre of buoyancy, the more stable the ship that is, the greater the force which must be applied to raise the centre of buoyancy above the centre of gravity and cause an overthrow. In other words the stability of a ship depends upon the relative positions of the centre of gravity and the centre of buoyancy. The centre of gravity is discovered by a calculation of the various weights making up the ship's total displacement. A similar series of calculations based on the form, or proposed form of the ship will determine the position of the centre of buoyancy. A graphic method of arriving at the same result consists of cutting from cardboard a series of cross-sections of the ship drawn to scale and gluing them together with their centre lines and load-water lines matching as in Fig.

717

2. Several groups of these cross-sections are made, one for each angle of rolling. Equidistant parallel lines are drawn across each model, representing the position of the vessel with different loadings. The divisions are cut

FIG. 2.

off in succession from the top line, and the remainder after each cutting is carefully weighed and recorded for purposes of comparison. Before each cutting the combination of cross-sections is suspended from a nail, allowing it to hang freely, and a plumb-line hung from the same point of support. The model is hung first from one corner and then from the other

as shown in Fig. 3, where PL represents the plumb-line in the first suspension, and its trace in the second suspension, QR the position of the plumb-line in the second suspension, and B the centre of buoyancy found by their intersection. From B a line is projected vertically upward that is at right angles to the waterline to which the ship is assumed to roll. The extension of that line until it meets the centre line GK of the ship's molded form gives the point M, known as the metacentre. In discussing the principles of flotation, the ship is often considered a pendulum whose point of suspension is at the metacentre. The higher this point is above the centre of gravity (G), the more stable the ship. As M is made by the molding or the loading to approach G, stability diminishes, and when M passes below G the equilibrium is unstable, and overturning is imminent. The horizontal distance (GZ) from

Finding the centre of gravity is a much more complicated process. The necessary calculations are too extended to be reproduced here and the reader is referred to technical works on shipbuilding for intensive study of the problem. A mechanical method is often employed and when extreme care is exercised the results are sufficiently accurate to serve every practical purpose. The "light" ship that is, with all its stores and equipment on board, but without cargo-is subjected to what is known as the "inclining experiment." The ship is heeled over from an upright position by the moving of a weight from one side to the other. The trial must be made in perfectly calm weather, in placid water, and the weight should be large enough to roll the vessel through an arc of at least two degrees. For a large liner, say of 70 feet beam, a weight of 10 tons is required. Pig iron is commonly used. A long plumb-line is suspended inside of the ship and its deflections marked. The metacentre having been previously determined by the finding of the centre of buoyancy, the remainder is easy.

Trim, as applied to a ship, is allied to its stability. The term signifies the condition of draught as related to its length. For example, if the draught forward is one foot less than the draught aft, the vessel is said to have a trim of one foot by the stern. A trim by the head would mean that the draught forward was the deeper.

Strength of structure is necessary to withstand the strains to which the ship is subjected by wind and waves. In order to calculate these strains the vessel is regarded as a girder supporting the various weights of cargo, engines, coal, etc., acting downward; and also acted upon by the lifting strain of buoyancy acting upward. This girder is studied in two situations: First, as lying across the trough between two waves, supported at each end by deep water with its large lifting strain and by shallow water with very little supporting power at the middle: this is called the "sagging" strain. The other critical position is that where the middle of the ship's length is supported by the deep water of the crest of a wave and both ends are in shallow water: this is called the "hogging" strain. These two conditions are illustrated at A and B respectively in Fig. 4. The strength of the ship proper

A

B

FIG. 4.

is thus quite distinct in meaning from the local strength of various parts designed for certain purposes, as for the distribution of the weight of the engines, the thrust of the propeller, the supports for hoisting cranes, and the like.

The capacity of a ship is her power of carrying stores and cargo, together with crew and passengers. The greater this capacity is in pro

portion to the size, and the greater the speed of the vessel, the greater is her utility. The more lightly a vessel is built the greater will be her capacity for her size; but the lightness of a vessel is limited by the need of strength to resist strain. Capacity is also to some extent dependent on form, and the form which is most conducive to high speed is not necessarily that which gives the greatest capacity for stowage. The speed of a vessel, as also facility of evolution or promptitude in obeying her helm, depends on the due proportion of her parts. Given an equal engine power, the speed of a vessel is dependent upon its underwater outlines. In a general way it may be said that the sharper the bows the more easily the resistance of the water is overcome; and long, gentle, horizontal curves are speedier than a straight, chisel-shaped form. Bevelling-up the bows from the keel to the deck tends to an increase of speed in two ways: it lowers the initial resistance of the water and causes a tendency of the bow to rise and ride upon the water, thereby diminishing the draught. Bevelling-up the stern is also of advantage, provided the tapering of the body of the ship does not begin too far forward. If begun at the midship section and curved in gently running lines aft, the speed will be increased. A similar result will be secured by curving the bottom of the ship gently upward from amidships toward the stern. The midship cross-section whose water surface most nearly approaches the semi-circle is the speediest. However, on account of its lack of stability and the very objectionable tendency to roll, it is used only when speed is the chief consideration. Figure 5 shows in diagram

FIG. 5.

matic form the shape and water-line found to be speediest under any given propulsion, the length being from 7 to 10 times the beam. It is common in swift river steamers, but is not used for cargo vessels, as it lacks in profitable carrying capacity. The midship section of the cargo ship is on the lines shown in Fig. 1.

Construction. In designing a ship the midship area is computed and a midship section made from which the proportions of the other parts of the ship are calculated. The whole plan of the ship is then drawn in three related sectional plans, called the sheer-plan, the bodyplan and the half-breadth plan. The sheer-plan is a projection on a vertical longitudinal plane dividing the ship on its centre line into two parts and gives a complete view of the side, representing the length, depth, rake of the stem and stern, with the wales, water-lines, decks, ports, masts and channels. The body-plan is a projection of the largest vertical and athwartship section, showing the breadth and having described upon it every timber composing the

frame of the ship, those running forward from the place of greatest breadth being described on the right hand, those running aft on the left of the centre line. The half-breadth plan shows the half-ship lengthwise as seen from above. The water-lines are drawn on the sheerplan as parallel straight lines; they are dotted in or drawn in blue ink on the half-breadth plan, and show the width and horizontal curves of the hull at different levels corresponding with the water-lines in the sheer-plan. Halfmodels of the vessel are also made. These are constructed of thin strips of wood laid horizontally on each other, which represent the parallel water-lines, and can be taken apart to serve as models for the full-sized drawing. When the plans are complete full-sized drawings are traced in chalk on the floor of a room called the mold-loft, which is usually of a length equal to half that of the largest ship, in addition to the whole height of her hull. This operation is called laying off the ship. It supplies the workmen with the exact shape and position of that which constitutes what is called the frame of the ship. Pine models are then made of the different parts. The material formerly used in ship construction was timber, but this is now superseded by iron, and iron again is being in most cases replaced by steel. Wood is rarely used except for the smaller sea-going

M

H

FIG. 6. Midship section of wooden vessel: A, keel; B, keelson; C, false keel; D, floor; EE, futtocks; F. top-timber; G, lengthening piece; HH, wales; I, diminishing planks; K, bottom planks; L. garboard strakes; M, beam; N, deck; O, shelf; P. waterway; Q, spirketting; R. clamps; S, knecs; T, side keelsons; V, limber strakes; W, rough-tree rail; X, mast.

vessels, coasting craft and small yachts and boats. In the haste to replace the shipping lost by the German submarine warfare the building of wooden ships was extensively revived. The materials commonly used for wooden vessels are oak, teak, cedar, pine, beech, elm and many others, some being more suitable for one purpose, and some for another. In forming the separate pieces of the frame, which is technically called the conversion of the timber, the principal points to be studied are the use of the proper wood to give the requisite strength, rigidity, elasticity or toughness to each part;

719

the selection of pieces from which the most important parts can be cut in the most perfect manner, and all the frame made as strong and free from faults as possible; and lastly, the economical use of timber. The last object is often found to be practically antagonistic to the others, for though a small gain which sacrifices the efficiency of a costly machine can never be dreamed of as economy, it is not always easy to hit the exact mean between waste of material and sacrifice of efficiency; and when a low prime cost is an object, false economy is often practised deliberately. It is one of the advantages of the use of iron that the cost of material can be more exactly proportioned to the degree of efficiency it is designed to secure.

Keel and Frame. The keel is usually made of elm, which is tough and not easily injured by water and is very suitable for receiving the numerous fastenings necessary to fit the other parts into it. In large vessels the keel is usually made of several pieces of timber scarfed together. The keel is not perfectly horizontal, but deeper at the stern than the bow, which gives the ship greater steadiness and freedom of motion. Below the keel is placed the false keel, of elm four to five inches thick, which protects the true keel from abrasion and gives greater steadiness to the ship. At both ends of the keel is placed the deadwood, which, cut into a curvilinear form at its upper surface, forms the line of the bottom of the ship's body. The stem and stern posts are set up at each extremity. The stem post is curved at its lower extremity. In a large ship it is divided into three pieces, called upper, lower and middle. The scarf which unites the stem post with the keel is called the boxing. The stern post is, if possible, made of one piece of oak, so as to have greater strength to support the rudder. It is inserted into the keel by tenons and mortices. The frame of the ship consists of floors, cross-pieces, futtocks and top timbers. The floor timbers are placed across the keel perpendicularly to its length, the upper surface of the keel and deadwood being cut to receive them. They are fastened in various manners. The timbers which join the floor are called the first futtocks. Other floors and futtocks are placed upon the first to complete the frame. The timbers of the frame below the surface of the water are curvilinear, above it nearly rectilinear. The distance between the frames is called room and space. Upon this the relative weight and strength of the ship greatly depend. The stemson is worked in as a support to the stem; the keelson, placed above the keels, serves to secure the floor timber and is scarfed to the stemson and sternson, which latter is bolted to the stern post. The beams which support the decks are received on longitudinal ribs called shelves, which form part of the frame, and above which are the waterways. frame being completed, the skin or planking is applied, the vessel being first set upright and plumbed to ascertain that her frame is duly proportioned. The outer planking of a large vessel of oak is three to six inches thick. It is fastened to the ribs by bolts and trenails or by plugs of oak tightened by wedges. The decks of a ship are not completely flat, but are set to the segment of a large circle, which enables them to throw off the water. The holes

The

for carrying away the water are called scuppers. The seams of the outer planking of a wooden vessel are made watertight by caulking. This is forcing oakum (see OAKUM), by means of sharp iron wedges called caulking irons, into the seams of the planking, which are forced

FIG. 7.

open by reaming irons. The seams are then payed with melted pitch. The decks are also caulked with oakum.

Iron and Steel.- For shipbuilding purposes iron and steel have been found by experience to be greatly superior to wood. An iron vessel is lighter than a wooden one of the same size, and with iron an equal strength may be obtained with less weight. Iron is also far more manageable than wood, as it can be bent with ease into any required shape. Steel is a still lighter material than iron. The same names for the different parts are generally retained in building with iron or steel, though they have little correspondence with the parts of a wooden vessel except in position. A diagram of half the midship section of a modern steel vessel is shown in Fig. 7. The keel is of far less importance than in wooden ships, and does not as in them hold the position of foundation or "backbone" to the whole structure, since an iron vessel is designed to be mutually supporting throughout. An iron ship, in fact, resembles a tubular iron bridge, closed at both ends, and the deck is of as much importance as the bottom to the strength of the whole. The keel is constructed of plates riveted together, and sometimes is made hollow. From it, and riveted to it on either side, rise the ribs, which are girders built up of plates, and to the ribs on the outside is fastened the plating. The plating consists of sheets of metal one inch or more in thickness, overlapping each other at the edges, where they

are riveted together at intervals of three and one-fourth to four inches. The plates vary in thickness according to position and strength required. Figure 8 shows the lines of plating as laid out on a body plan. There may be an inner skin of plating as well as an outer, and this of course adds to the strength and safety of the vessel. The ribs are tied together and at the same time held rigidly in place by means of iron, which support the deck or decks. The decks consist of wooden planking with thin metal plates below. In the finer class of ships there are water-tight partitions or bulk-heads of iron stretching across the vessel from side to side and from keel to deck, with water-tight doors in them, so that if in case of an accident the water gets into one of them the rest may keep the ship afloat.

Fabricated Ships.-The term "fabricated ship" signifies a type of steel vessel on which the punching and shaping of plates and "shapes" and a part of the assembling and rivetting is done in a shop ordinarily employed in structural iron work; as, for instance, bridge building, or steel frames for skyscrapers. This plan, a strictly American idea put into operation during the Great War, and adopted at once by most of the shipbuilding nations, has the great advantage of utilizing the expert knowledge of steels and the superior special equipment of the steel worker's shop for the manufacture of parts amounting to about 80 per cent of the weight of steel in a vessel. It has been found practicable to make the entire centre body of the ship in this way, leaving only the bow and stern to be fabricated in the shipyards. The result has been that about 40 per cent of the time of the expert shipwright has been saved for work that only he could do, and the yearly output of the shipyards of the country has been increased proportionately.

Launching. The launching of a vessel is a delicate operation, and, as marking the completion of the most important labors of the

FIG. 8:

shipbuilder, is usually made the occasion of a public exhibition and celebration. Two parallel inclined platforms of solid timber are laid one on each side of the keel, at the distance of a few feet from it and extending from the stem