MANAGEMENT OF SHIPS. 101 



Frigates were formerly used for this purpose. Steamships, however, on 

 account of their swiftness and abihty to move in any direction, are far 

 more convenient. Fig. 4 represents the moment of battle. At a are 

 seen the two battle lines, and at b the grappling between two hostile fri- 

 gates. 



The order of retreat is shown in pL 28, Jig. 5, although in fact this is 

 usually governed by circumstances. The fleet is here formed in two lines, 

 AB and BC, forming an obtuse angle, the vertex of which is made by 

 the admiral's ship in the centre of the fleet. The frigates, fireships, &;c., 

 form two other lines, EF and FG, to the leeward of the former. 



It is important to know the different methods by which manoeuvres can 

 be performed in one and the same sailing order, without breaking it. We 

 cannot here consider the subject at length, but must be content with repre- 

 senting the movements by figures, with a few words in explanation. 

 Figs. 6 and 7 show two methods, by which columns can sail both by day 

 and night without disturbing their ranks. Fig. 8, the columns turn before 

 the wind. Fig. 9, the columns sail in two different directions close to the 

 wind. Fig. 10, manoeuvre by which the centre column is changed into 

 the windward column. Fig. 11, change of the windward column into the 

 leeward column. Fig. 12, change of the centre column into the leeward 

 column. Fig. 13, manoeuvre of the windward column in order to sail 

 to the leeward. Fig. 14, manoeuvre of the leeward column in order to 

 advance to the leeward. 



When the admiral has ordered a ship to a certain position, it is the duty 

 of the commander of the ship to obey the orders promptly, and to make 

 good the position required, cost what it may. For this purpose, the so 

 called ship's square has been invented (Jig. 15). Let the figure be the 

 ground-plan of a ship, EF a portion of the longitudinal axis lying over the 

 keel, and ABCD a square in which the line EF passes through the inter- 

 section of the two diagonals, then will the angles DGE and CGE be each 

 equal to 135°, and these will be the two courses in which the ship sails 

 close to the wind. If now these angles are bisected by the lines GH and 

 GI, these lines will indicate the direction of the wind on the tacks. Hence, 

 if a ship in the direction EF sails on the starboard tack, its course by the 

 wind will be on the semi-diagonal GD, and if it sails on the larboard tack 

 in the direction EF, its course will be on the semi-diagonal CG. Applying 

 this result to a fleet, which sails in three columns, the front coinciding with 

 the direction of the wind (Jig. 16), it follows that all the ships must sail 

 parallel with each other and the line drawn through the main-masts of 

 three ships (one of each column) will, in hke manner, be parallel with 

 the front line. If we now place the ship's square around the centre ship, 

 the coinciding ships in the columns, as respects the tacks and the winds, 

 will lie in the direction GH and GI, while the ships of each column with 

 their longitudinal axes lie in FE or parallel with it. 



The ships sometimes by accident fall out of the line, and it is important to 

 restore the line of battle immediately. The chief rule in this case is for the 

 ship which was at the head of the line to pass to leeward behind the front, 



ICONOGRAPHIC ENCYCLOPEDIA. — VOL. III. 48 ToS 



