The necessity of transmitting information in a private manner taxed the ingenuity of many during the Revolutionary War. Clever ideas were experimented with, but none were more practical than those used by General Washington’s spies. True, when they first realized the necessity of secrecy a very crude method was adopted, originating with Abraham Woodhull and used first in his letter of April 10th, 1779. This was the use of the figures 10 for New York, 30 and 40 for Post Riders and 20 for Setauket. By July of that year Major Tallmadge had prepared pocket dictionaries for the General, the Culpers, and himself. These consisted of closely written columns of figures and words, arranged on a double sheet of foolscap paper. The words were those they would be most apt to need, extracted from a copy of Entick’s Dictionary and written in columns in alphabetical order. Then opposite each word was placed a number and this number was thereafter used to designate the word. Then there were proper names, beginning with General Washington 711, General Clinton 712, Tryon 713, Erskine 714, Vaughan 715, Robinson 716, Brown 717, General Garth 718, Lord North 719, Germain 720, John Bolton 721, Sami. Culper 722, Culper Junr. 723, Austin Roe 724, C. Brewster 725, Rivington 726. Then 37 places have numbers assigned them, and there is an alphabet for words not listed and letters for numerals. These tables were used to the close of the war.

Much more important to the Secret Service of General Washington was the use of an invisible stain which required developing with another chemical before the writing became visible. It reached the Culpers about the time the above dictionary was prepared but was first proposed to General Washington in a letter from John Jay, a facsimile of which is opposite [page 52]. In another chapter his brother, James Jay, tells how he invented this stain, and its practical use. It was an important factor in the success of the service and it is regrettable that no one ever sufficiently thanked the Jays for it. The Culpers were frequently asking for more of it, and General Washington, low in funds, had to depend upon James Jay to furnish it. Becoming a tax upon his resources he found it necessary to explain the situation to General Washington in the following letter:

Fishkill, Septr. 19, 1780.

Dear Sir: I am extremely sorry it has not been in my power to supply you sooner with the medicine. The disagreeable situation which I have hithertoo been in, owing to a very considerable loss I am likely to sustain by the new System of Finance, deprived me of that pleasure; for I am always happy to have an opportunity of showing that I am, with great esteem and respect, Dear Sir, Your most Obt. & hemble Servt.

James Jay.

At times, because of lack of funds to purchase it the Culpers were without the Counterpart to develop the letters from Headquarters, and sometimes they had no stain with which to write their intelligence. They guarded well its discovery, in fact so well that the matter was never mentioned historically until now although several incorrect guesses were made as to the method they used to convey their messages.

More clever than those written between the lines were their letters addressed to prominent Tories. These could be sent with fair assurance of safety. The messenger knew of course that they were not to be delivered to the party addressed and discovery of them in his possession would only have disarmed suspicion. Their only rival in cleverness was the British Headquarters, where André and DeLancey exerted themselves. Like the early attempts on the American side those used by the British were sometimes more ingenious than efficient, as exemplified in the silver bullets which were used to convey messages between Generals Burgoyne,[59] Clinton, and Howe. Experiences of several of these messengers are historically recorded. One courier being cautioned that upon no account was the message to be delivered to anyone besides General Burgoyne unless it was General Clinton himself, suspecting that he was in territory occupied by the British, was surprised when challenged, but declared himself to be a friend of General Clinton’s and asked to be taken to him. He had no knowledge that there was a Clinton on both sides and not until he found himself in the presence of General George Clinton did he discover his mistake. Then he swallowed the silver bullet, but it was too late. His action had been observed and he was immediately taken into custody, when being interrogated as to what business he had with General Clinton, and discovering some embarrassment in his answer, it was proposed to administer an emetic, to ascertain what he had swallowed with such precipitation. The idea was adopted, and the consequence was that he threw up the silver ball; which being unscrewed was found to contain important intelligence. The courier was of course hung as a spy.

General Washington believed more could be accomplished by strategy than by bullets. He was careful to conceal his plans during the war but when peace came he permitted to be published in the “Columbian Centinal” a letter which he wrote from Mount Vernon, dated July 31, 1788.[60] The following extracts from this letter give an interesting angle to the campaign around New York:

“It was determined by me, nearly twelve months before hand, at all hazards, to give out, and cause it to be believed by the highest military as well as civil officers, that New York was the destined place of attack, for the important purpose of inducing the eastern and middle States to make greater exertions in furnishing specific supplies, than they otherwise would have done, as well as for the interesting purpose of rendering the enemy less prepared elsewhere. It never was in contemplation to attack New York, unless the Garrison should first have been so far degarnished to carry on the southern operations as to render our success in the siege of that place, as infallible as any future military event can ever be made.... That much trouble was taken and finesse used to misguide and bewilder Sir Henry Clinton, in regard to the real object, by fictitious communications, as well as by making a deceptive provision of ovens, forage, and boats, in the neighborhood, is certain: Nor were less pains taken to deceive our own army; for I had always conceived, where the imposition does not completely take place at home, it would never sufficiently succeed abroad.... Your desire of obtaining truth, is very laudable; I wish I had more leisure to gratify it as I am equally solicitious the undisguised verity should be known. Many circumstances will unavoidably be misconceived, and misrepresented. Notwithstanding most of the papers, which may properly be deemed official, are preserved; yet the knowledge of innumerable things, of a more delicate and secret nature is confined to the perishable remembrance of some few of the present generation. With esteem, I am, Sir, your most obedient humble servant.

“Go. Washington.”