Sentence:  Here an estate, which would plant 103 acres of canes, would, I presume, to be <WSD>well-handed</WSD>, have 250 negroes, young and old, which may all, except infants and the very aged, be said to contribulte less or more to the cultivation of the cane; but deducting 100 for infants' nurses, and other ineffective hands, we have, for the remaining 150, 906 lbs each. 
Meaning of the word marked with <WSD> tags:  Well-supplied with slaves.