Spy System 1777 
Page VI
Washington sent a missive to Clark on or about December 15, but the letter is again lost to history. Clark's missing letter apparently advised Washington that the British were offering compensation for supplies they had commandeered or payments for fresh supplies. On December 16 Washington replied from his brief encampment at Gulph Mills, approving a plan for members of Clark's spy network to participate, especially if, during the course of visiting Philadelphia to receive the payments, they were able to glean any potentially valuable intelligence:
Altho' I would not grant permission to all those who want to go into Philada to get paid for what they were plundered of, you may allow it to those on whom you can depend and from whom you expect any intelligence in return. I have directed that all passes granted by you shall be sufficient for the purposes you want them.
Clark's spies had failed to apprise him of Cornwallis's foraging expedition into Lower Merion Township on December 11-12 which nearly brought on a clash with Washington's vanguard as it marched from Whitemarsh towards Gulph Mills. But with rumor prevalent in the city that the enemy were again intending to move, and with the failure to notify Washington of Cornwallis's recent march in mind, Clark was determined to provide Washignton with accurate intelligence concerning the next British movements, reporting to Washington in his December 19th letter:
I dispatched several Spies into the City, to endeavor to find the intended hour of the Enemy's march; one of them this moment returned from Philada, which place he left at three oClock this afternoon . . . there is no talk at present of their moving-their light Horse were reconnoitring this morning on Marshalls Road, & very inquisitive -I directed my Spy to inform them a large Body of Troops were marching towards Darby, there to take post for the Winter, which startled them, he says, . . . the Inhabitants immagine the Enemy mean to remain quiet in winter quarters, they say, they intend to extend their ditch to join the line at the upper Ferry . . . I expect further information every moment, which will be perfectly satisfactory with respect to the Enemy's further intentions.
On December 20th, the day after the Continental Army marched from Gulph Mills to Valley Forge, Clark notified Washington that:
. . . near 1000 of the Enemy, crossed over to Jersey yesterday with six feild pieces from 4 to 6 pounders, with design to let the Country people have the benefit of the Market . . . about 30 Waggons escorted by 100 Hessians, went a forageing towards Derby & returned loaded with Hay & Rye straw without interruption. . . they intend to make another forageing excursion haul all the Wood they've cut, over the River, & then pull up or destroy the Bridge & remain quiet in winter quarters for the remainder of the Season
If the latter information was correct, Washington could be reassured that the enemy did not intend to attack his ragged, starving army at Valley Forge. Nevertheless, he would have to remain very watchful.
General Daniel Morgan, general from Virginia and hero of Saratoga
E. Benjamin Andrews, 1895
(note that Morgan was not promoted to General until 1794)
By December 21st Clark could notify Washington that:
A spy from the city and the express arrived a few minutes ago. The former confirms the account of the enemy's intentions to plunder. They intend to visit Derby, Marple, and Springfield townships this week . . . I am just informed Morgan's corps is in this neighborhood; should the enemy make any sudden move I will give the Col. notice, and every thing in my power shall be exerted to secure you the most instant intelligence of their moving . . . The enemy are busy turning the inhabitants of Philadelphia out of their houses, and quartering troops in them. Many of the citizens are obliged to live in their kitchens, and permit those tyrants to occupy their houses.
A major enemy forage towards Chester commenced on the 22nd. Clark immediately wrote to Washington:
A large Body of the Enemy are on their march to Derby, where they must have arrived by this time, the number uncertain, but you may rely are formidable, they certainly mean to forage where I mentioned in my Letter of Yesterday-at 8 this morning about 20 Dragoons of the Enemy came up to the Fox Chase, to give the alarm, & then took the route to Derby-I have alarmed Morgan-the Genl is rode out but is expected every moment-If a Corps was thrown instantly toward Middle ferry their retreat is inevitably cut off.
