Adams’ departure was premature, but expected. The redcoats under Gen. William Howe didn't enter Philadelphia until a week later, but Howe’s designs on Philadelphia had been well known in advance, even in Braintree, Mass.
In a letter to Abigail dated Sept. 1777, John Adams wrote,
How much longer Congress will stay is uncertain. I hope we shall not move until the last necessity, that is, until it shall be rendered certain that Mr. Howe will get the city. If we should move, it will be to Reading, Lancaster, York, Easton, or Bethlehem, some town in this state. It is the determination not to leave this State. Don't be anxious about me, nor about our great and sacred cause. It is the cause of truth and will prevail. If Howe gets the city, it will cost him all his force to keep it, and so he can get nothing else.
Abigail Adams was more anxious than John about the coming events. James Lovell, another member of the Second Continental Congress, sent her a letter that she feared contained the news that John Adams was sick or dead.
The letter actually included a plan of the part of the country where the next phase of the war was likely to be fought.
On Sept. 17, 1777, Abigail Adams wrote to her husband describing her feelings upon receiving Lovell’s letter:
…there is no reward this side the grave that would be a temptation to me to undergo the agitation and distress I was thrown into by receiving a letter in his handwriting, franked by him. It seems almost impossible that the human mind could take in, in so small a space of time, so many ideas as rushed upon mine in the space of a moment. I cannot describe to you what I felt.
The sickness or death of the dearest of friends, with ten thousand horrors, seized my imagination. I took up the letter, then laid it down, then gave it out of my hand unable to open it, then collected resolution enough to unseal it but dared not read it; began at the bottom, -- read a line,--then attempted to begin it, but could not. A paper was inclosed; I ventured upon that, and finding it a plan, recovered enough to read the letter; but I pray Heaven I may never realize such another moment of distress.
Two days later, John Adams described in his diary how he was rushed out of Philadelphia, not yet knowing it was a false alarm:
1777. SEPTR. 19. FRYDAY.
At 3 this Morning was waked by Mr. Lovell, and told that the Members of Congress were gone, some of them, a little after Midnight. That there was a Letter from Mr. Hamilton Aid de Camp to the General, informing that the Enemy were in Possn. of the Ford and the Boats, and had it in their Power to be in Philadelphia, before Morning, and that if Congress was not removed they had not a Moment to loose.
Mr. Merchant and myself arose, sent for our Horses, and, after collecting our Things, rode off after the others. Breakfasted at Bristol, where were many Members, determined to go the Newtown Road to Reading. We rode to Trenton where We dined. Coll. Harrison, Dr. Witherspoon, all the Delegates from N.Y. and N.E. except Gerry and Lovell. Drank Tea at Mr. Spencers, lodged at Mr. S. Tuckers, at his kind Invitation.