Discusses their correspondence and speculates that not all their letters reach each other. Discusses the recent British victories in taking Long Island and New York. Had hoped the victories would induce the British into an ill-planned and unsuccessful attack. Discusses the transportation of lumber. Asks his brother if he believes British General William Howe will attempt to end the war decisively this winter, if he believes France will assist the colonies, if he thinks the Continental Congress is taking proper actions to form the army. Notes that he will relay information about artillery pieces to Henry Jackson. Indicates that General Philip Schuyler has put in his resignation. Discusses selling various pieces of furniture.

Expresses disappointment with not receiving a letter from William, but writes this letter for both William and Henry Jackson. Discusses being recalled from New Jersey in response to sightings of British ships. Tells William to not give credit to reports that an American garrison has been taken, because it has not be verified. Comments on cannons he is getting for Henry Jackson to be mounted on a privateer. Mentions that Lucy Knox and their daughter visited briefly. Composed at Mount Washington.

Complains that Henry has not written to him recently and explains how he has received information from Lucy Knox and Mrs. Jonathan Pollard. Claims that they do not have many good sources for the news in Boston. Indicates that a British ship called the Mifford is seizing any vessel that comes near it in the bay. Mentions plans to mobilize troops from Connecticut. Notes that Benjamin Franklin, Edward Rutledge, and John Adams were being sent by Congress to meet with William Howe, a peace conference that later proved unsuccessful. Mentions reports of a battle on Lake Champlain. Business has improved in Boston. Notes that it is his twentieth birthday.

Congratulates his brother on his escape from New York. Notes that many in Boston are much pleas'd with the retreat. Tells the version of events in New York he has heard but eagerly awaits details from Henry. Notes hearing that Benedict Arnold returned safely to Fort Ticonderoga, after hearing earlier that he had lost his fleet. Discusses extending civilities to Doctor Samuel Stringer, who had done the same when William and Henry were in Albany and Fort George obtaining artillery pieces for the siege of Boston, on his visit to Boston. Mentions business and privateering activities.

Discusses a British ship that was captured near an American fort at Nantasket, Massachusetts. The vessel had come from Ireland to support General William Howe's army and had mistakenly thought the British were still in Boston. Tells a detailed story about how the Committee of Correspondence and Safety ordered every man between sixteen and sixty to gather with full military accoutrements and drafted thirty-two of them to join the invasion of Canada. Many men ran away but the draft was eventually made by offering larger bounties. The debacle caused some to call for the removal of John Brown, the chairman of the Committee. Also discusses the activities of his company, commanded by Henry Jackson, at the event. Notes that there is no other news, business has been slow, and that the town has been made exceedingly dull with the smallpox.

Discusses corresponding with his brother. Describes the artillery department in the Continental Army as one of the busiest, and the reason he cannot write as frequently as would prefer to. Gives his analysis and opinions of recent events, commenting on British activities and George Washington's leadership, the poor quality of officers the Continental Army, the failures of the Continental Congress, and the needs of the army. Believes that the Battle of Long Island was their one chance to win New York. Comments on the morale-boosting effects of the small victory at the Battle of Harlem Heights. Gives instructions to pay Major John Crane and a message for Henry Jackson. Written at Harlem Heights in New York (16 September 1776.).

Chastises William for not writing more. Discusses the recent Tory plot to either capture or assassinate George Washington and the subsequent hanging of a member of the General's Guard named John Rickey, a misidentification of Thomas Hickey, the only person hanged for the conspiracy. Discusses General William Howe's position at Sandy Hook with 130 ships and his ability to strike the city in about three hours. They are expecting an attack any time and Henry speculates that if Howe comes up like a man and brings his ships too before our Batteries, there must be the finest sight...that ever was seen. Discusses the Continental Army's preparedness, mentioning that he has 1200 men and that the inhospitable sentiment in New York has bolstered their determination. Reports that Lucy, General Greens lady [Catherine Green], and Mrs. Jonathan Pollard have gone to Fairfield, Connecticut. Discusses the invasion of Canada, indicating that the Continental Army has been forced back and hopes to make a stand at Fort Ticonderoga and Crown Point. Asks William to inform Captain Ebenezer Stevens wife that he loves her. Also asks him to show this letter to Mr. Jackson, possible Henry Jackson, and to tell him that he spoke with George Washington about ordering arms. Hopes to inform William of the campaign's commencement in his next letter. Offers salutations to friends and family in Boston from himself and Lucy Knox and reminds William to take care of the business there. Mentions that twenty two men and four officers were taken from a ship called the Greyhound. The expected attack did not occur until 12 July 1776.