A flag of truce is white, both at sea and on land, but on board ship it is customary to hoist with it the national flag of the enemy--the white flag at the main and the enemy's ensign at the fore. On one occasion during the war in 1814 when the French frigate _Clorinde_ was about to be attacked by the British frigate _Dryad_, the commander of the former, being desirous to ascertain what terms would be granted in case he surrendered, hoisted French colours aft and English colours forward. Under cover of this the French frigate sent a boat with the message. The answer was a refusal to grant any terms, but the boat was allowed to return to the French frigate in safety before the _Dryad_ filled and stood towards her. The Ensign and Pendant at half-mast are the recognised signs of mourning. Sometimes also it is an expression of mourning to set the yards at what seamen call "a-cock-bill," that is all the yards topped up different ways on each mast; but this is chiefly done by foreigners, who, on Good Friday and other occasions, set their yards thus. It is also customary as a sign of mourning to paint the white lines of a ship of a blue colour. In older times, when ships were more gaudily painted and gilded than they are now, they were painted black all over as a sign of mourning. The red or bloody flag is a signal of mutiny, and as such it was displayed in our own navy on two noted occasions in the end of last century, when the fleet at Spithead mutinied, and afterwards that at the Nore. In the latter case the mutineers hauled down the flag of Vice-admiral Buckner and in its stead hoisted the red flag. It is a singular fact, however, and characteristic of the British seaman, that on the 4th of June, the king's birth-day, while the mutiny was at its height, the whole fleet, with the exception of one ship, evinced its loyalty by firing a royal salute, and displaying the colours usual on such occasions, the red flag being struck during the ceremony, and only re-hoisted when it was over.[40] [40] James' _Naval History_, ii. p. 73. The yellow flag is the signal of sickness and of quarantine. USE OF FLAGS IN NAVAL WARFARE. Such are the principal naval flags. Of the circumstances in which they may or may not be legitimately used, especially in naval warfare, some interesting stories might be told.