"Alas! there are some stupid souls, formed of such phlegmatic, adverse materials, that you might sooner strike conception into a flannel petticoat--or out of one--(now keep your temper I beg, sweet Sir) than convince their simple craniums that six and seven makes thirteen."
— Sancho, Charles Ignatius (1729-1780)
(II.xlii, pp. 100-2; pp. 181-2 in Carretta)
See Letters of the Late Ignatius Sancho, An African. In Two Volumes. To Which Are Prefixed, Memoirs of His Life (London: Printed by J. Nichols, 1782). <Link to text from Documenting the American South at UNC>
Reading Letters of the Late Ignatius Sancho, ed. Vincent Carretta (New York: Penguin, 1998).