Crafty Codes of American Spies: How George Washington's intelligence gatherers enciphered their communiques

This story first appeared in 1998 as part of "Long Island: Our Story"

Fearing that their messages might get intercepted by the British, the Culper spies quickly resorted to both secret code and invisible ink.

Here is the beginning of a coded letter sent by Abraham Woodhull, alias Culper Sr., to Gen. George Washington.

"729 29 15th 1779.

"Sir. Dqpeu Beyocpu agreeable to 28 met 723 not far from 727 & received a 356 . . . Every 356 is opened at the entrance of 727 and every 371 is searched, that for the future every 356 must be 691 with the 286 received."

Translated, it reads:

"Setauket August 15th 1779

"Sir. Jonas Hawkins [an early messenger] agreeable to appointment met Culper Jr. not far from New York & received a letter . . . Every letter is opened at the entrance of New York and every man is searched, that for the future every letter must be written with the ink received."

Though the codes used by the Culper spies were elementary by today's standards, they apparently were good enough for the Revolutionary War. It wasn't until 1939 that historian Morton Pennypacker revealed the Culper secret code system for the first time. He said that Maj. Benjamin Tallmadge, Washington's spy chief, prepared codebooks for four people: Washington, Abraham Woodhull, Robert Townsend, alias Culper Jr., and himself. He took hundreds of words from a commonly used dictionary of the day, then assigned numbers to each word.

All the spies, as well as other people important to the ring, also were given numbers. For example: Washington was 711; Tallmadge, 721; Robert Townsend, 723. Many places were given numbers: New York, 727; Long Island, 728; London, 746. There were numbers for the months of the year. And for each of the 26 letters of the alphabet, a different letter was substituted, a so-called substitution cipher.

Even more important to the spy ring was the use of invisible ink, called by Washington a "sympathetic stain," or "white ink." It had been invented by James Jay, a physician living in England, the brother of John Jay, who would become the first chief justice of the United States. The invisible ink was first used on a blank piece of paper, which, after the message was written, was inserted in a half-ream of new paper. By an earlier agreement, Washington knew by counting from the top of the half-ream how to find the page with the message. He would then use a second solution to make the message reappear. Later, thinking that carrying a blank piece of paper might invite suspicion, Washington ordered the invisible messages to be written between the lines of, or under, a regularly written message.

Spying was a risky game, and great chances were taken by all the members of the ring. In October, 1779, Culper Sr. wrote to tell the general about getting mugged on Long Island.

"It is too great a risque to write with ink in this country of robbers. I this day just saved my life. Soon after I left Hempstead Plains and got into the woods I was attacked by four armed men, one of them I had frequently seen in N. York. They searched every pocket and lining of my clothes, shoes, and also my saddle, which the enclosed was in, but thank kind Providence they did not find it. I had but one dollar in money about me. It was so little they did not take it, and so came off clear."

Though Washington was publicly a reticent man, he occasionally made clear his approval of the work of the Culper Spy Ring. Of Culper Jr., he wrote on Feb. 5, 1780: "His accounts are intelligent, clear and satisfactory ... I rely upon his intelligence." In May, 1781, Washington recorded in his diary: "Of the Culpers fidelity and ability I entertain the highest opinion."

With the war officially ended in 1783, the Culper Spy Ring disbanded.

VEILED MESSAGES

Here is a sampling of the secret code used by Gen. Washington, Benjamin Tallmadge, Robert Townsend and Abraham Woodhull. Each of the four men had a codebook of hundreds of commonly used words that were assigned two- or three-digit codes:

*Each letter had a substitute for spelling words

a = e
b = f
c = g
d = h
e = i
f = j
g = a
h = b
i = c
j = d
k = o
l = m
m = n
o = p
p = r
q = k
r = l
s = u
t = v
u = w
v = x
w = y
x = z
y = s
z = t 

AFTER THEIR REVOLUTION WAS WON

Here is what happened to the chief players in the Culper Spy Ring:

Benjamin Tallmadge (1754-1835) settled in Litchfield, Conn., where he became a merchant. He represented his district as a Federalist in the U.S. House of Representatives from 1801-1817. He died in 1835 at age 81.

Abraham Woodhull (1750-1826) returned to his farm. He served as judge of the Court of Common Pleas for six years, then was named a Suffolk County judge, 1799-1810.

Robert Townsend (1753-1838) returned to his Oyster Bay home, continuing his work as a merchant and helping to manage the estate of his father, Samuel Townsend.

Austin Roe (1749-1830) continued operating Roe's Tavern in Setauket. In 1798 he moved to Patchogue, where he founded Roe's Hotel.

Caleb Brewster (1747-1827), who settled in Fairfield, Conn., was pensioned by Congress for gallantry in action in a whaleboat raid. For many years he was the captain of a revenue-cutter (an armed government vessel used to prevent smuggling) in the New York area.

Anna Smith (Nancy) Strong (1740-1812) remained on Strong's Neck in Setauket after her husband, Selah, was released from a British prison in New York and took the children to Connecticut. At war's end the family was reunited in Setauket, where the family property was restored to its former status as St. George's Manor.