The American heritage

Two paintings very closely allied to the American heritage have just changed hands - one for a record $3.25 million, the other for a hefty but undisclosed sum (although it is now valued at $1 million.)

Both paintings date from the early years of the nation, are by major American artists, and will join museum collections. The larger of the two, and the one that established the record price for an American work of art, is Samuel F. B. Morse's ''The Gallery of the Louvre.'' The other is a portrait of Thomas Jefferson executed by Gilbert Stuart for Jefferson's grandson, Col. Thomas Jefferson Randolph, sometime between 1805 and 1809.

Although best known as the inventor of the telegraph and Morse code, Samuel F. B. Morse was also one of our most distinguished painters of the first third of the 19th century. He was not satisfied, however, with what he could learn about art in the US, and so sailed for Europe in 1829 to study Renaissance and baroque painting styles from the masterpieces hanging in the great European art collections.

He was particularly impressed by what he saw in the Louvre and in 1831 decided to paint a picture of one of its galleries filled with many of the great works of that museum. He worked on it from late fall of that year until August 1832, when he left Paris to return to New York. He took the painting with him, and completed it - by painting in the many tiny frames on the pictures depicted - in August 1833.

It was unveiled in New York that same year, and although it never had quite the impact upon the public Morse had hoped it would, it was moderately well received. Among those who saw and liked it was James Fenimore Cooper. Unable to buy it himself, Cooper encouraged his neighbor, George Hyde Clark, to do so. The painting eventually found its way into the collection of Syracuse University, where it remained until its recent sale to Daniel J. Terra through Coe Kerr Gallery, for the Terra Museum of American Art in Evanston, Ill.

In fact, 1982 is turning out to be a banner year for Morse, with two major exhibitions devoted to him. From Sept. 14 through Oct. 23, the Grey Art Gallery and Study Center in New York's Greenwich Village will show ''The Paintings of Samuel F. B. Morse'' - which will include ''The Gallery of the Louvre.'' And from Sept. 22 through Nov. 18 the National Academy of Design on upper Fifth Avenue will present an in-depth study of Morse as artist, scientist, and educator.

The other major early American work to change hands recently, Gilbert Stuart's portrait of Jefferson, is believed to be the only one Stuart painted of the third President from life. Known as the ''Edgehill'' portrait, it remained in private hands from the time of its commissioning to its recent sale to R. Crosby Kemper, who donated it to the National Portrait Gallery in Washington.

Before moving there permanently, however, the portrait will be on public display for two months beginning Sept. 9 at the Nelson Gallery in Kansas City, Mo.