ON APRIL 12, 1790, Rachel Peale, the first wife of the artist Charles Willson Peale, died of lung disease--the result of a cold that was exacerbated by the strain of giving birth to her 11th child. Distressed at losing his wife of 28 years and hoping frantically that she would revive, Peale sat with her corpse in a locked room for almost three days, unwilling to allow the women to "lay her out."

A year later, at age 50, Peale remarried and started a second family.

Peale's second wife, Betsey DePeyster, bore him six children, five of whom lived to maturity. She died in 1804 during the difficult birth of her seventh baby, and in the spring of the following year, Peale took as his third wife the Quaker Hannah Moore. When Hannah died in 1821 of yellow fever, he waited five years -- a long time for Peale to be without a wife. Then, at age 85, he went a-courting for a fourth time. But Mary Stansbury was not interested in exchanging her handicapped students for an aged artist. As John Neal, a Philadelphia art critic, wrote of him that year: "Old Mr. Peale is one of the best men that God ever made, though he will paint portraits with a chisel, marry a fifth or sixth wife every few years, and outlive all the rest of the world."

When I escort visitors through the current exhibition, "Charles Willson Peale and His World," at the National Portrait Gallery the question that frequently is asked about this talented 18th-century artist is: Why did he marry so often? Was he so unfeeling that he sought to replace his wives almost as soon as he had worn them out? Should I reply that Peale had strong sexual needs? That he needed someone to look after his large brood of children? That with all his many enterprises and unceasing occupation he was lonely?

Having lived closely with Peale for eight years as editor of his papers, I can say that there is some truth in these answers. And it should be remembered that deaths and births were common facts of 18th-century life. Yet not all 18th-century widowers remarried as often as Peale. His good friend Thomas Jefferson, for example, lost his wife early in their marriage and, despite the fact that he enjoyed the company of clever and beautiful women, never remarried. Nor did all approve of Peale's behavior. Peale had won the prize twice "in the lottery of marriage," the architect Benjamin Henry Latrobe wrote to Jefferson, and "Prudence would not have advised a third risk . . ." Noting Peale's "fry of five or six little uneducated children" and his lack of savings, Latrobe concluded that "Peale is a boy in many respects."

Latrobe misjudged the artist. Peale's youthfulness stemmed from a large supply of energy, unflagging curiosity about the world, and an inventiveness that sought to use all that nature offered. His many marriages resulted from his frank acceptance of his sexuality. He also liked children, and occasionally quoted the aphorism that "he who forgets that he was once a child himself, is neither fit to be a father nor a master." But Peale also believed in marriage as a social institution. Marriage, he wrote in his "Essay to Promote Domestic Happiness" (1812), is "a social bond . . . by which harmony, industry and the wealth of the nation are promoted."

Peale's study of nature reinforced his sense of the family as the center from which social benefits radiated. As a wedding present, Peale presented his third wife with books on natural history to prepare her for her work as mother to his motherless children. From a study of insect life she would discover, he thought, that even insignificant creatures possess beauty. In the habits of dogs, bats, monkeys, wolves and other mammals, she would find worthwhile examples of domestic harmony and parental concern.

Family harmony and parental love and responsibility become themes in many of Peale's paintings. In "The Gittings Family," grandparents clasp hands while cuddling a grandchild who holds a chipmunk--symbol of the natural world. "Mrs. James Smith" shares Hamlet's soliloquy with her grandchild; "Thomas McKean" passes on his commitment to law and justice to his son. Peale instructs his family in God's design for the world in the "Exhumation of the Mastodon," and in the fine art of drawing in "The Peale Family."

As these paintings illustrate, Peale was convinced that the education of the next generation in morality as well as in art and science took place in the family circle. Here were taught discipline, balance, duty and benevolence: virtues highly important to the young American republic. Family harmony established the foundation for social harmony and, eventually, harmony among nations.

Lillian B. Miller is historian of American culture at the National Portrait Gallery and editor of the Peale family papers. The exhibit "Charles Willson Peale and His World" is at the National Portrait Gallery until Jan. 2. First Hand is a weekly column written by people in the arts.