The British Are Coming. Rick Atkinson

of nails,” a supply officer warned, while another advised in late July, “We are in want of soap for the army.” American troops—badly housed, badly clothed, and badly equipped—were at war with the world’s greatest commercial and military power, long experienced in expeditionary administration. As an ostensible national government, Congress had begun to improvise the means to fight that war, from printing money and raising regiments to collecting supplies. But the effort thus far seemed disjointed and often half-baked. Although Congress had appointed quartermaster and commissary chiefs, the jobs were neither defined nor supported, and other critical supply posts—notably for ordnance and clothing—would not be created for another eighteen months.

      Simply feeding the regiments around Boston had become perilous. Commissary General Joseph Trumbull, a Harvard-educated merchant and another of the Connecticut governor’s sons, frantically tried to organize butchers, bakers, storekeepers, and purchasing agents. Coopers were needed to make barrels for preserved meat, and salt—increasingly scarce—was wanted to cure it. Forage, cash, and firewood also grew scarce; an inquiry found that much of the “beef” examined was actually horse. To feed the army through the following spring, Trumbull told Washington, he needed 25,000 barrels of flour, 13,000 barrels of salt beef and pork, 28,000 bushels of peas or beans, 11 tons of fresh beef three times a week, and 22,000 pints of milk, plus 200 barrels of beer or cider, every day, at a total cost of £200,000. By late September, as prices spiraled and supply agents rode to New York to beg for flour, Trumbull worried that by spring the army would face starvation and thus have to disband. “A commissary with twenty thousand gaping mouths open full upon him, and nothing to stop them with,” he wrote, “must depend on being devoured himself.”

      But no shortage was as perilous as that discovered in early August. Washington’s staff calculated that an army of twenty thousand men, in thirty-nine regiments with a hundred cannons, required two thousand barrels of gunpowder—a hundred tons. Powder was the unum necessarium, as John Adams wrote, the one essential. Each pound contained roughly seven thousand grains, enough for a volley from forty-eight muskets. A big cannon throwing a 32-pound ball required eleven or twelve pounds of powder per shot; an 18-pounder used six or seven pounds. A survey taken soon after Washington’s arrival reported 303 barrels in his magazines, or fifteen tons—enough to stave off a British attack, but too little for cannonading. “We are so exceedingly destitute,” he told Hancock, “that our artillery will be of little use.”

      Precisely how destitute became clear from the report laid before the war council that convened at Vassall House on Thursday, August 3. The earlier gunpowder estimate had erroneously included stocks used at Bunker Hill and in various prodigal skirmishes over the summer. Despite generous shipments to Cambridge from other colonies, the actual supply on hand, including the powder in all New England magazines, totaled 9,937 pounds, less than five tons, or enough for about nine rounds per soldier. Washington was gobsmacked. “The general was so struck that he did not utter a word for half an hour,” Brigadier General John Sullivan told the New Hampshire Committee of Safety. “Everyone else was equally surprised.” When he finally regained his tongue, Washington told his lieutenants that “our melancholy situation” must “be kept a profound secret.” This dire news, he added, was “inconceivable.”

      More orders fluttered from the headquarters, along with desperate pleas. “Our situation in the article of powder is much more alarming than I had the most distant idea of,” Washington wrote Congress on Saturday. “The existence of the army, & the salvation of the country, depends upon something being done for our relief, both speedy and effectual.” Every soldier’s cartridge box was to be inspected each evening; some regiments levied one-shilling fines for each missing round. Civilians were asked “not to fire a gun at beast, bird, or mark without real necessity.” Even the camp reveille gun should be silenced. Desperate raids were contemplated, to Halifax or Bermuda. Pleading “the most distressing want,” Massachusetts requested powder from New York, which replied that it, too, was “afflicted and astonished,” with less than a hundred pounds for purchase.

      A rebel schooner from Santo Domingo, in the West Indies, sailed up the Delaware River in late July under a false French flag with almost seven smuggled tons hidden in the hold beneath molasses barrels. Loaded into a half dozen wagons, the powder was promptly sent north with an armed escort. A second consignment of five tons soon followed, and by late August Washington had enough for twenty-five rounds per soldier, still a paltry amount. War could not be waged with an occasional smuggled windfall, yet not a single American powder mill existed when the rebellion began. Mills operating during the French war had fallen into disrepair or been converted to produce flour or snuff. Of particular concern was the shortage of saltpeter—potassium nitrate, typically collected from human and animal dung, and the only scarce ingredient in gunpowder. Identified as a strategic commodity in the medieval Book of Fires for the Burning of Enemies, saltpeter had been imported to Europe from India through Venice for centuries; imperial Britain bought almost two thousand tons a year. The saltpeter was kneaded with small portions of sulfur and charcoal, then pulverized, dusted, glazed, and dried to make gunpowder.

      Saltpeter recipes soon appeared in American newspapers and pamphlets for patriots willing to collect the “effluvia of animal bodies” from outhouses, barns, stables, tobacco yards, and pigeon coops, preferably “moistened from time to time with urine.” Massachusetts offered £14 per hundred pounds, triple the price paid by Britain for Indian saltpeter. “I am determined never to have saltpeter out of my mind,” John Adams declared in October. “It must be had.”

      Yet it would not be had in sufficient quantities to supply Washington’s magazines, which also lacked bayonets, good muskets, cartridge paper, bullet lead, and even shaped flints. In the next two years, at least 90 percent of American gunpowder, or the saltpeter to make it, would somehow have to come from abroad. For now, the shortage required “a very severe economy,” as one Washington aide wrote, curtailing tactical operations and imposing a quiescent status quo on the siege of Boston. By early fall, virtually all American cannons had fallen silent but for a single 9-pounder on Prospect Hill, fired occasionally in ornery defiance.

      As Washington grappled with his powder problems, another shock jolted the American camp. On Tuesday, October 3, nine generals gathered for a war council with the commander in chief in a large front room at Vassall House. Outside the south windows, autumn colors tinted the elm trees, and the distant Charles glistened with a pewter hue. Wasting no time, Washington informed the council that an anonymous, encrypted “letter in characters,” addressed to a British major, had been intercepted in Newport, Rhode Island, and brought to the Cambridge headquarters. The original courier, a woman described by her former husband as “a very lusty woman much pitted with smallpox,” had been apprehended and bundled to Cambridge on the rump of a horse for interrogation.

      Washington dramatically placed the pages on a table. An unbroken, nonsensical sequence of letters covered the first sheet for twenty-six lines, then spilled onto a second page. After the letter’s capture, he said, two copies had been sent for decipherment to trusted men with a knack for puzzles. This code substituted a different letter for each letter in the alphabet; it could be solved by identifying the most frequently used symbols in the cipher and assuming they represented the most common letters in English, starting with e, then t, then a, then o, and so forth. Both decryptions had been completed the previous night, and the solutions were identical.

      Washington laid one of the translations before his lieutenants. The letter, more than 850 words long, provided details on American strength, artillery in New York, Bunker Hill casualties, troop numbers in Philadelphia, ammunition supplies, and recruiting. “Eighteen thousand brave & determined with Washington and Lee at their head are no contemptible enemy,” the writer had advised. “Remember I never deceived you.… A view to independence grows more and more general.… Make use of every precaution or I perish.”

      From clues in the letter and a confession extracted from that lusty, pitted courier the secret author had been identified as Dr. Benjamin Church, recently appointed as the army’s surgeon general. He had been arrested, Washington said, and was confined to a room on the second floor of his hospital headquarters, just down the street from Vassall House. A search of his papers had yielded no incriminating evidence.

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