. Call it, for abbreviation, h (half blood).The whole commerce between master and slave is a perpetual exercise of the most boisterous passions, the most unremitting despotism on the one part, and degrading submissions on the other. Our children see this, and learn to imitate it; for man is an imitative animal. This quality is the germ of all education in him. From his cradle to his grave he is learning to do what he sees others do. If a parent could find no motive either in his philanthropy or his self-love, for restraining the intemperance of passion towards his slave, it should always be a sufficient one that his child is present.
THOMAS JEFFERSON, Notes on the State of Virginia, 1790
MR. FRANCIS C. GRAY
March 4,1815 Monticello
Sir,
You asked me in conversation, what constituted a mulatto by our law. And I believe I told you four crossings with the whites. I looked afterwards into our law, and found it to be in these words: “Every person, other than a Negro of whose grandfathers or grandmothers anyone shall have been a Negro, shall be deemed a mulatto, and so every such person who shall have one-fourth part or more of Negro blood, shall like manner be deemed a mulatto”; L. Virga 1792, December 17: the case put in the first member of this paragraph of the law is exempli gratia. The latter contains the true canon, which is that one-fourth of Negro blood, mixed with any portion of white, constitutes the mulatto. As the issue has one-half of the blood of each parent, and the blood of each of these may be made up of a variety of fractional mixtures, the estimate of their compound in some cases may be intricate, it becomes a mathematical problem of the same class with those of the mixtures of different liquors or different metals; as in these, therefore, the algebraical notation is the most convenient and intelligible. Let us express the pure blood of the white in capital letters of the printed alphabet, the pure blood of the negro in the small letters of the printed alphabet, and any given mixture of either, by way of abridgment in MS. letters.
Let the first crossing be of a, pure negro, with A, pure white. The unit of blood of the issue being composed of the half of that of each parent, will be . Call it, for abbreviation, h (half blood).
Let the second crossing be of h and B, the blood of the issue will be 
, or substituting for 
its equivalent, it will be 
, call it q (quarteroon) being 
negro blood.
Let the third crossing be of q and C, their offspring will be 
, call this e (eighth), who having less than of a, or of pure negro blood, to wit 
only, is no longer a mulatto, so that a third cross clears the blood.
From these elements let us examine their compounds. For example, let h and q cohabit, their issue will be 
, wherein we find 
of a, or negro blood.
Let h and e cohabit, their issue will be 
, wherein 
a, makes still a mulatto.
Let q and e cohabit, the half of the blood of each will be
wherein 
, of a is no longer a mulatto, and thus may every compound be noted and summed, the sum of the fractions composing the blood of the issue being always equal to unit. It is understood in natural history that a fourth cross of one race of animals with another gives an issue equivalent for all sensible purposes to the original blood. Thus a Merino ram being crossed, first with a country ewe, second with his daughter, third with his granddaughter, and fourth with the great-granddaughter, the last issue is deemed pure Merino, having in fact but 
of the country blood. Our canon considers two crosses with the pure white and a third with any degree of mixture, however small, as clearing the issue of the negro blood. But observe, that this does not re-establish freedom, which depends on the condition of the mother, the principle of the civil law, partus sequitur ventrem, being adopted here.
But if e emancipated, he becomes a free white man, and a citizen of the United States to all intents and purposes. So much for this trifle by way of correction.
His long legs under the full-length gray frockcoat shifted position, itching for the feel of his horse Eagle between them. He was seventy-two years old. His presidency was six years behind him and those six years had been spent here at home, in retirement, surrounded by those he loved most in the world: his women, his children, his grandchildren, his slaves, his neighbors, his kin. Restless, he rose from his writing table to his full height, the face ascetic and serene in the bright light. He sat down again, and his left hand took up his pen, and as it did, the copying machine he had invented by which a letter written manually with one pen was simultaneously traced with another by a series of connected levers, called a polygraph, followed the movements of his hand. This would be the last letter of the morning.
He looked out of his study windows: it was a view in which nothing mean or small could exist, he thought. That was why he had chosen the site, which commanded the Blue Ridge Mountains: it was one of the boldest and most beautiful horizons in the world. His house, which he called Monticello, giving it the soft Italian pronunciation, stood upon a plain formed by cutting off the top of the mountain.
The light this morning is so pure and delineating, he thought, touched with the soft promise of spring that turns the mountains their deepest blue.
He stared for a moment more at the west lawn, noting several figures gamboling on it—children, he supposed. He smiled. Whoever they were, black or white, they belonged to Monticello. And to him.
He turned his eyes away and picked up his pen. Absently, he massaged his wrist before signing: Thomas Jefferson.