Sentence:  I suppose it is a truth too well attested to you, to need a proof here, that we are a race of beings, who have long labored under the abuse and censure of the world; that we have long been looked upon with an eye of contempt; and that we have long been considered rather as brutish than human, and scarcely capable of mental <WSD>endowments</WSD>. 
Meaning of the word marked with <WSD> tags:  Something with which a person or thing is endowed.