Were Nicholson's contractors too cash poor to use slaves?

Thanks to his speculator bankruptcy, the papers of the Pennsylvania speculator John Nicholson were preserved. Most of the letters pertaining to his effort to develop his property in Washington are from the men he hired who were desperate for cash to carry on their work. The March 1, 1797, letter below is from William Tunnicliff who ran an inn on 6th St. SE just off Pennsylvania Avenue and tried to develop it and the area around it.

Tunnicliff had a least one slave but this letter suggest that most of his workmen were free. He promises Nicholson that if he does send down some cash "say to amount of 50 Dollars per week will you know go but a little way with the workmen, if I have it, it shall be faithfully distributed amongst them to the best of my Judgement."

Of course, money need not be divvied out to slaves, and it is likely that masters did not hire out their slaves to men like Tunnicliff who, thanks to Nicholson not sending the money he promised, quickly got the reputation for not paying what he owed.