France officially joined the American colonies in their struggle for independence on February 6, 1778. On this day two treaties were signed: the first was the Treaty of Alliance and the second was the Treaty of Amity and Commerce. The American Commissioners who signed the treaties were Benjamin Franklin, Silas Deane, and Arthur Lee. There was only one French Commissioner who signed the treaty, Conrad Alexandre Gerard. Having served with distinction in other diplomatic positions, in 1774 Gerard had been appointed the first secretary of the French Minister of Foreign Affairs. After successfully representing France at the negotiating table with the American colonies, King Louis the XVI recognized his achievement by appointing him the first accredited French minister to the American colonies. On April 10, 1778, Gerard (and Silas Deane) departed from Toulon aboard Admiral Charles Henri Hector, the Comte d’Estaing’s ship Languedoc; on July 6, the French fleet arrived in Delaware Bay.Learning that a British fleet that had been in the area had already departed, d’Estaing prepared to set sail for New York. Before departing, he wrote two letters. The first was to General Washington:
I have the honor of imparting to Your Excelly the arrival of the King’s fleet; charged by his Majesty with the glorious task of giving his allies the United States of America the most striking proofs of his affection. Nothing will be wanting to my happiness if I can succeed in it; it is augmented by the consideration of concerting my operations with a General such as Your Excellency . . . Mr. Dr. Chouin,a Major of infantry in the King’s service, has orders to present to you this—I pray you to grant the most extensive confidence in all this officer shall tell you on my part.
The second was to Henry Laurens, President of the Continental Congress:
I have written to his excellency Gen. Washington and shall dispatch two officers . . . to his headquarters with an offer of combining my movements with his . . . I hope the Authority of Congress will leave him at liberty to take advantage of them, and that we shall be able to immediately . . . act in concert for the good of the common cause . . . his excellency Mr. Gerard . . . hastens to reside near Congress & there employ the character with which his majesty has invested him . . . I have the honor to assure you[r] excellency that I shall make it my duty & pleasure in executing whatever Mr. Gerard shall promise. The assurances which he shall give will require no farther ratification on my part.
Two days later, on July 10, Laurens wrote to Washington,
Capt. Selby . . . had fallen in with the French Fleet Eastward of Bermuda—the Admiral had taken him on board & enjoined him to Pilot the fleet to the Coast—the fleet arrived near Chincoteague [Virginia] in the Evening . . . [The next day] Selby was sent on Shore in order to procure Pilots—he engaged six to go on board the French fleet . . . They had originally intended for Delaware but hearing that the Enemy was gone to New York they required Pilots to conduct them to Sandy Hook . . . I shall endeavor to reach Count d’Estaing with the necessary advices on the Coast of New Jersey . . . Your Excellency will, if he shall have proceeded nearer Sandy Hook endeavor to meet him with a Letter.
On the same day, Silas Deane wrote to Laurens,
Finding that the Enemy had escaped the Admiral resolved instantly to pursue them to New York and will sail this morning for that Port, but he has no pilot; If therefore pilots can be sent to meet him on his arrival, it will be of the utmost service to the expedition. I shall embark this afternoon in company with his Excellency Monsr. Gerard for Philadelphia . . . His Excellency the Admiral desires, that on the arrival of the pilots at the hook where they will find his fleet, that they would make a Signal with a white flag, either onboard their Boat, if they have one, or, from the Shore, formed in a triangle.
The entire letter from Deane to Laurens was read in Congress the next day. Before the day’s session was over the Congress adopted the following Resolutions:
That General Washington be informed by Mr. President, that it is the desire of Congress that he co-operate with his excellency Count d’Estaing, commander of a French squadron now on the coast of North America, and proceeding to New York, in the execution of such offensive operations against the enemy as they shall mutually approve
That General Washington be empowered to call on the states of New Hampshire, Massachusetts bay, Connecticut, Rhode Island, New York, New Jersey, or such of them as he shall judge proper, for such aids of their militia as he shall think requisite for carrying on his operations in concert with Count d’Estaing, commander of the French fleet; and that it be earnestly recommended to the states above mentioned, to exert themselves in forwarding the force which may be required from them with the utmost despatch.
After the session, the Continental Marine Committee sent the following letter to the Continental Navy Board of the Eastern Department:
Congress being determine[d] to give every possible aid to the execution of so Salutary a purpose has directed us to order all the Continental frigates and armed Vessels within your Department to be immediately made ready for Sea and dispatched one after An Other as soon as each can be prepared, to join the Squadron of France and to act in such manner as the Count D’Estaing shall judge most proper for distressing and destroying the enemys force upon the Coast of North America. Congress trust[s] to the bravery and good disposition of the American Seamen that they will . . . step forth with alacrity and exert themselves in Supporting our friends who have come so far to assist us to vanquish an enemy too long triumphant upon the Sea.
Also on the 12th, Washington wrote back to the Laurens,
We have had it reported for two or three days, through several channels from New-York, that . . . the Enemy have been manning with the utmost dispatch several of their Ships of war . . . and have pushed them out to sea
and the Comte d’Estaing received a letter from the Continental Marine Committee of the Congress:
The marine Committee of Congress have received information that the Squadron under your Excellencies command has occasion for a supply of water and fresh provisions and . . . to furnish both with all possible expedition. The frigate Chimere and the two Vessels with her, will be dispatched immediately with as much water as we can find Casks for . . . The same vessels will bring your Excellency some hundred barrels of bread and flour, with a small supply of fresh provisions. A Commissary has orders quickly to collect near Shrewsbury and Hook 50 bullocks, 700 sheep, with a quantity of vegitables and a number of poultry.
On July 13, d’Estaing informed Washington,
The desire of communicating speedily with your Excellency determines me to make a debarkation upon the coast of Jersey . . . The first moments are so pretious, above all upon Sea. That it may be of the greatest importance for me to be informed four and twenty hours sooner or later of the projects of Your Excellency.
Washington, awaiting the arrival of Major Chouin, d’Estaing’s representative, in camp, decided, in turn, to send Lt. Col. John Laurens, an Aide-de-camp and the son of President Henry Laurens, as his representative to d’Estaing. John Laurens informed his father of his mission:
the general has thought proper to send me with dispatches [to Count d’Estaing] I must immediately prepare for my Journey and Voyage—I . . . wish that Mons, le Comte were furnished with a proper number of intelligent Coast pilots—that as many pilot boats Schooners and other small swift sailing Vessels were employed under the conduct of judicious Seamen to reconnoitre the Enemys fleet whenever it appears at Sea.
The next day Washington sent a letter to Henry Laurens:
Colonel Laurens . . . will set out this morning with a letter to the French Admiral the Count d’Estaing inclosing a copy of yours, and such other information as I have [been] able to collect. Its further purpose is for the establishing a convention of signals in case of co-operation; or to convey him such a knowledge of the enemy’s naval force and position.
And another to d’Estaing:
I would submit it to your consideration whether it will not be expedient to establish some conventional signal, for the purpose of promoting an easier correspondence between us . . . if you deem it expedient, you will be so obliging as to fix upon them with Lieut. Col. Laurens, one of my Aids, who will have the honor of delivering you this, and of giving you satisfaction in any particulars respecting our Affairs, and to whom you may safely confide any measures or information, you may wish me to be acquainted with.
The same day d’Estaing wrote to Conrad Alexandre Gerard, the French Minister to the Continental Congress, informing him he would be sending “Recognition Signals” to him and asked him to deliver them as soon as possible to Henry Laurens. On the 15th, the signals were delivered by Gerard to Congress where they were read and then referred to the Marine Committee.
The following are the four sets of signals:
Signals by day of Ships of the Squadron
When a ship of the squadron wants to make itself known by an American ship, it will place three flags, thus
On the foremast or the foreyard:
A red flag with a red pennant above, if the day of the month is odd
A blue flag with a red pennant above, if the day of the month is even
On the mainmast, or on a mainyard
A red flag if the day of the week is Sunday, Monday, Tuesday or Wednesday
A white flag if the day of the week is Thursday, Friday of Saturday
At the peak of the mizzenmast
A jack for the first fifteen days of the month
When a ship of the squadron will have approached the American ship, it will lower and raise three time successively its flag at the peak of the mizzenmast, and then, if it judges appropriate, it will discharge a cannon from each side.
If the Americans ship on its part has made its signals and the French ship wants to indicate that it has seen them well, it will lower to a third of its height the flag on the foremast and then hoist it again. The signals having been perceived well by both parties, if the French ship has need of speaking with the American ship, it will lower its flags fore and aft and keep only the one on the mainmast: if it does not want to speak with it, it will lower all its flags.
Signals by day of the American Ship
When an American ship wants to make itself known by a ship of the line or frigate of the squadron, it will put on its flagstaff or on its mainmast any flag folded into a triangle, and when it has kept it in place for some time, it will lower or raise it several times in succession; thus
3 times, if the day of the month is even, and the day of the week is Sunday, Monday, Tuesday or Wednesday.
5 times, if the day of the month is odd, and the day of the week is similarly Sunday, Monday, Tuesday or Wednesday.
7 times, if the day of the month is even, and the day of the week is Thursday, Friday or Saturday.
9 times, if the day of the month is odd, and the day of the week is Thursday, Friday or Saturday.
He will repeat by intervals, if he judges it necessary, two or three times the same signal, until the French ship indicates that it has seen it by lowering its flag on its foremast to a third of its height and hoisting it again.
If the American ship has cannon or swivel guns, it will fire, if it judges appropriate, a shot from each side.
The signals having been well seen by both parties, if the American ship has need of speaking with the French ship it will keep its flag flying and it will lower it if it does not want to speak with it.
Signals by Night
When during the night an American ship wants to make itself known to a ship of the squadron, and reciprocally, they will place a lantern in the area of the vessel the most obvious and cover and uncover it several times in succession, at very distinct intervals, and as equal as they are able to do it; thus
4 times if the day of the month is odd, and the day of the week is Sunday, Monday, Tuesday or Wednesday.
6 times if the day of the month is even, and the day of the week is Sunday, Monday, Tuesday or Wednesday.
8 times if the day of the month is odd, and the day of the week is Thursday, Friday or Saturday
and 10 times if the day of the month is even, and the day of the week is Thursday, Friday or Saturday.
They will repeat thereupon two or three times the same signal while leaving an interval of three or four minutes between the repetitions.
Then, in the case that they want to converse, they will keep their lantern uncovered, if not, they will extinguish it.
When an American ship finds itself in a fog and within speaking distance of a ship it judges to be of the French squadron, and to which it wants to make itself known, it will fire two shots from swivel guns or two volleys of several muskets if the day of the month is even, and three shots from swivel guns or three volleys of several muskets if the day of the month is odd.
The ship of the squadron in a similar case wanting to make itself known by an American ship will fire three shots from swivel guns or three volleys from several muskets if the day f the month is even, and two shots from swivel guns or two volleys from several muskets if the day of the month is odd.
When the two ships are within speaking distance, they will hail, then the one that will have hailed first will say its word of recognition to which the other ship will respond with its own. The word of recognition of the American ship will be Trenton and independency, that of the French ship will be Saratoga and liberty.
On the same day, d’Estaing received a note from Gerard informing him that Captain Selby had sent him seven pilots.
For the next couple of weeks William Livingston, the governor of New Jersey, Jonathan Trumbull, the governor of Connecticut, and the Continental Marine Committee continued to supply d’Estaing’s squadron with fresh meat, vegetables and water and to seek pilots who could safely lead them to Sandy Hook.
Major Chouin arrived in Washington’s camp on the 17th. Washington later that day wrote to d’Estaing,
Mr. De Chouin . . . has given me a very full and Satisfactory explanation . . . of your situation and views and in return, I have freely communicated to him my Ideas of every matter interesting to our mutual operations . . . You would have heard from me sooner in answer to your letter [of July 14] but I have been waiting for Mr. Chouin’s arrival to acquaint me with your circumstances and intentions, and, at the same time, have been employed in collecting information with respect to several particulars, the knowledge of which was essential to the formation of our plans.
At the same time d’Estaing was writing to Washington,
I have occupied myself less with delivering the number of English vessels of war in the Rhode of Sandy Hook than the means of entering it . . . [The] superiority of number . . . of the English navy will not hinder me from attacking Lord Howe . . . if the depth of the water do not forbid me . . . Mr. Laurens will tell you more than I can write. But it will be very important that the arrival of so great a naval succor should produce at the same time a general effort by land. If unfortunately that should be impossible you are too good a patriot and too great a soldier, not to feel the necessity, I shall be under to going to seek elsewhere an opportunity of injuring our common enemy.
On the 18th, Washington wrote to Governor Trumbull,
I . . . had the pleasure of receiving a Letter from the Admiral Count d’Estaing, dated off the Sandy Hook where he now lies with twelve Sail of the Line and four Frigates. The British fleet are within the Hook . . . I am so fully convinced of the advantages that will result from having all our Frigates, Privateers, and armed Vessels of every kind cruising off the East end of Long Island, that I have . . . wrote to the same effect to the States of Rhode Island and Massachusetts. The British fleet are awed by the French, will be obliged to keep together, which will afford the noblest opportunity to our Cruisers to pick up whatever is inward bound.” 
The next day, Henry Laurens also wrote toTrumbull:
I am called upon by His Excellency Le Sr Gerard, Minister Plenipotentiary from His most Christian Majesty . . . in order to obtain from Connecticut such Aids as His Excellency Count D’Estaing . . . may stand in need of . . . I . . . address your Honor requesting you to afford all assistance in your power to Count D’Estaing . . . particularly that a sufficient number of skilful Pilots may be held in constant readiness for conducting the Fleet
On the 20th, Lt. Col. Alexander Hamilton, another of Washington’s aides-de-camp, informed the General,
d’Estaing has had the River sounded and finds he cannot enter, He will sail for Rhode Island . . . He would sail immediately but he waits the arrival, or to hear, of a frigate which carried Mr. Gerard to Delaware, and which he appointed to meet him at Sany Hook, so that he fears, his sudden and unexpected departure, before she arrives might cause her to be lost . . . We have agreed, that five cannons briskly shall be a signal of his arrival by day, and the same number, with five sky rockets signal by night.
On the 22nd, Washington informed Henry Laurens how he and d’Estaing came to conclude that Rhode Island was a better point of attack than Sandy Hook and that he had informed the local commander in Rhode Island “that an Expedition might take place in a short time against Rhode Island and urged him . . . to make every possible preparation of boats—provisions—pilots, etc. . . . as if the event was fixed and certain.”
Our Letter to you on the 11 will convey our Instructions for every possible endeavour being exerted in preparing for Sea the Continental Vessels of war in your department and for sending them out one after another to join the Squadron of France . . . We enclose herewith A Set of Signals received from the French Admiral, Copys of which you will deliver to our Commanders enjoining great Secrecy and in case of necessity that they destroy them.
From this point till the end of the war, American ships and French Ships were able to communicate, support, and fight side by side along the coast and at sea.
Languedoc, twelve sail of the line ships and four frigates (a number of the ships were brand new). Worthington Chauncey Ford, ed., Journals of the Continental Congress (Washington DC: Library of Congress, 1908), 11:683.
Vice-Admiral d’Estaing to George Washington, July 8, 1778, in David R. Hoth, ed., The Papers of George Washington, Revolutionary War Series, 1 July—14 September 1778 (Charlottesville: University of Virginia Press, 2006), 16:38-39.