Laborers and the Potomac Canals, February 19, 1793

"Thomas Johnson,who succeeded Washington as president of the [Potomac] Company, persuaded the directors to hire slaves because "their labor will be more valuable than common white Hirelings."

Quote from Slave Labor in the Capital, page 44  

George Washington and the men he appointed as commissioners to prepare the City of Washington for the reception of the Federal government thought the success of the capital depended on opening the Potomac to navigation from Georgetown to Cumberland, Maryland. Work on canals around the falls of the Potomac began in the mid-1780s relying mostly on Irish laborers.

While Washington was president of the company, the frequent absenteeism of indentured Irishmen  prompted the company to advertise for slaves to hire. Thomas Johnson pushed the idea, writing to Washington in September 1785 that he and co-director Thomas Sim Lee, thought "it desirable to have Negroes as well as purchase servants....." (Bacon-Foster p 161) But, as Washington explained to him in a 20 December 1785 letter, the effort to hire slaves failed:

It is to be apprehended, notwithstanding the great encouragements which have been offered by the Directors of the Company for the hire of negroes, that we shall not succeed in obtaining them. An idea is entertained by the proprietors of them, that the nature of the work will expose them to dangers which are not compensated by the terms. [White indentured] Servants I hope are purchased 'ere this. Colo. Fitzgerald was to have gone yesterday day to George town for this purpose.

Johnson became president of the company in 1789 and shortly after that the company advertised for 200 slaves. (Bacon-Foster, pp. 175-6). I am not sure how many slaves that effort netted, but slaves probably never made up a majority of the workers. As late as 1793 company officials could only muster a crew of 60 hired slaves organized for the express purpose of replacing white indentured servants when they succumbed to the summer heat, at least that seems to be the implication of one official's report to President Washington

Geotown Feb 19, 1793,

Sir,

Knowing it will give you pleasure to hear of any thing favorable to the Navigation of the Potomac. I take the Liberty to inform you, we have now 150 Labourers employed at the Little Falls, under industrious overseers, and either Capt. Gilpin or myself see them at least once a week and the work goes on equal to our most sanguine expectations. We shall begin to fix the locks early next month & I am fully of opinion by the 1st of August the canal and locks will be compleat for boats to pass through & by the first of October the Navigation will I expect be Compleat from tide Water to the Great Falls so that by a short Portages at the Great Falls, the Navigation may then be in use to New Creek 24 Miles above Fort Cumburland, as boats now come down from thence into the Canal at the Great Falls. we have made Contracts to Compleat during the present Year, almost the whole of the Navigation above the Great Falls. - with some difficulty we have obtained about 60 Negroes for the year. They will be a good standby, when the sickly season comes on, when the white will leave us. I am with great Respect Your Obt Servt

Will. Deakins Junr

In the George Washington Paper, there is a payroll of the workers hired by the company in 1786. The laborers do indeed appear to be Irish. No hired slaves are listed. You can find a larger image here: http://memory.loc.gov/mss/mgw/mgw9/002/0003.jpg