In reading the above paragraphs one cannot fail to be impressed by the profound grasp of the essential requirements of the subject exhibited by the writer. Nothing like it appears again until modern times, and the concluding words might well have been written by Kempenfelt and the other reformers of the Signal System in the British navy at the end of the eighteenth century. After Leo we meet with nothing further on this subject until the middle of the fourteenth century, and from what we then find it is clear that the art had not only made no progress in the interval, but on the contrary had decidedly deteriorated. Two sets of instructions preserved in the _Black Book of the Admiralty_, to which Sir Travers Twiss assigns a date between 1337 and 1351[345], contain each one flag signal; one for calling a council, the other for notifying the presence of the enemy: _A xviii._ Item est assavoir que a quel temps convenable il plest a ladmiral dassembler les capitaynes et les maistres de la flotte conseiller avecques eulx il prendra hault en mylieu du mast de sa nef une banniere de conseil parainsi que en toutes parties de la flotte, soit en ports ou dehors sur la mer, ce pourra estre congnu et apperceu &c et doncques tantost les capitaynes et maistres de nefs sont tenuz dassembler sans delay avec leurs bateaux bien eskippez de mariners pour nager et aler en la nef de ladmiral pour illecques oyr et faire ce que le conseil de ladmiral aura ordonne. _B vi._ Item en cas que aucune nef ou outre vessel de la flotte apperceyue aucun vessel ennemy sur la mer doncques il mettra une banere en hault par laquelle la nef de ladmiral et autres nefz de la flotte pourront avoir congnoissance qu'il a veu ung vessel ennemy ou plusieurs et ainsi apres ordonner le mieulx quilz sauront pour lencontrer, &c. xviii. Also it is to be noted that at whatever convenient time it pleases the admiral to call together the captains and masters of the fleet to take counsel with them he will carry high in the middle of the mast of his ship a banner of council so that in all parts of the fleet, whether in ports or out at sea, this may be recognised and perceived etc., and then immediately the captains and masters of ships are bound to assemble without delay with their boats well manned with seamen to row and go on board the ship of the admiral there to hear and do what the council of the admiral shall have ordained. Item in case any ship or other vessel of the fleet perceive any enemy vessel upon the sea then he shall put a banner aloft by which the ship of the admiral and other ships of the fleet may have knowledge that he has seen one or more enemy vessels and thus afterwards give the best orders they know of to encounter it.